2-8-2, Usage, Thailand (Siam)
After the Second World War, in 1946, the RSR imported fifty used United States Army Transportation Corps S118 Class locomotives, the so-called MacArthur Locomotives. Another eighteen new engines of the same Class were purchased around 1948-1949 to meet the post-war demand.


2-8-2, Usage, Thailand (Siam)
The last type of Mikado steam locomotives for Thailand were seventy engines imported by SRT from Japan between 1949 and 1951, numbered 901 to 970. Of these, only Mikado no. 953 is still serviceable, even though it is no longer actively in use.


2-8-2, Usage, United Kingdom
The 2-8-2 wheel arrangement was rarely, but successfully, used on British rails. Sir Nigel Gresley of the London and North Eastern Railway (LNER) designed two Mikado types of note:


2-8-2, Usage, United Kingdom
The Great Western Railway (GWR) operated a class of 54 2-8-2T engines that had been rebuilt from 2-8-0T locomotives by Charles Collett, chief mechanical engineer of the GWR. As early as 1906, the chief mechanical engineer at the time, G. J. Churchward, planned a class of Mikado tank engines to handle heavy coal trains in South Wales. The plan was abandoned, however, as it was feared they would be unable to handle the sharp curves present on Welsh mineral branches. Instead, Churchward designed the 4200 Class of 2-8-0 tank engines, of which nearly 200 were built.


2-8-2, Usage, United Kingdom
In the 1930s, coal traffic declined with the result that many of these engines stood idle, since their limited operating range prevented them from being allocated to other mainline duties. Collett, as Churchward's successor, decided to rebuild some of the 4200 Class engines as 2-8-2Ts. The addition of a trailing axle increased the engine's operating range by allowing an increased coal and water storage capacity. Altogether 54 locomotives were modified in this manner. The 7200 Class tank engines, as they were known, remained in service until the end of steam in Britain in the early 1960s.


2-8-2, Usage, United Kingdom
The designer of the BR Standard Class 9F locomotive as well as the rest of the BR standard classes as Chief Mechanical Engineer of British Railways, Robert Riddles, originally designed the aforementioned locomotive to be a 2-8-2 using the boiler from one of the 4-6-2 passenger locomotive standard classes. However, he later decided to use a 2-10-0 wheel arrangement with a new boiler design, as it offered more tractive effort and better weight distribution.


2-8-2, Usage, United States
The 2-8-2 saw great success in the United States, mostly as a freight locomotive. In the 1910s it largely replaced the 2-8-0 Consolidation as the main heavy freight locomotive type. Its tractive effort was similar to that of the best 2-8-0s, but a developing requirement for higher speed freight trains drove the shift to the 2-8-2 wheel arrangement.


2-8-2, Usage, United States
The Mikado type was, in turn, ousted from the top-flight trains by larger freight locomotive wheel arrangements such as the 2-8-4, 2-10-2, 2-10-4 and articulated locomotives, but no successor type became ubiquitous and the Mike remained the most common road freight locomotive with most railroads until the end of steam. More than 14,000 were built in the United States, about 9500 of these for North American service, constituting about one-fifth of all locomotives in service there at the time. The heaviest Mikados were the Great Northern's class O-8, with an axle load of 81,250 pounds (36,854 kilograms).


2-8-2, Usage, United States
Almost all North American railroads rostered the type, notable exceptions being the Richmond, Fredericksburg and Potomac, the Boston and Maine, the Delaware and Hudson, the Western Maryland, the Cotton Belt and the Norfolk and Western. The largest users included the New York Central with 715 locomotives, the Baltimore and Ohio with 610, the Pennsylvania Railroad with 579, the Illinois Central with 565, the Milwaukee Road with 500, the Southern with 435, and the Chicago, Burlington and Quincy with 388.


2-8-2, Usage, United States
A number of North American 2-8-2s have been preserved as either static display pieces, or steam excursion stars. These include Baltimore and Ohio No. 4500, Nickel Plate Road 587, Grand Trunk Western 4070, Southern Railway 4501, Chicago, Burlington and Quincy 4960, Spokane, Portland and Seattle 539, Southern Pacific 745, Tremont and Gulf 30, Duluth and Northern Minnesota 14, Soo Line 1003, and Pennsylvania Railroad 520.


2-8-2, Usage, Yugoslavia
Borsig-built 2-8-2s were delivered to the railway of the Kingdom of Yugoslavia in 1930. These became the JDZ class 06, of which a few remain in the former Yugoslav nations.


2-8-2+2-8-2
Under the Whyte notation for the classification of steam locomotives by wheel arrangement, a 2-8-2+2-8-2 is an articulated locomotive using a pair of 2-8-2 power units back to back, with the boiler and cab suspended between them. The 2-8-2 wheel arrangement has a single pair of leading wheels in a leading truck, followed by four coupled pairs of driving wheels and a pair of trailing wheels in a trailing truck. Since the 2-8-2 type was known as Mikado, the corresponding Garratt and Modified Fairlie types were usually known as Double Mikado.


2-8-2+2-8-2, Overview
The 2-8-2+2-8-2 wheel arrangement was used by Garratt and Modified Fairlie locomotives.


2-8-2+2-8-2, Overview, Garratt locomotives
The Double Mikado was the fourth most common Garratt type, with 144 examples constructed, 114 built by Garratt patent owner Beyer, Peacock and Company (BP) and thirty built by others under license. Only ten, six for Chile and four for Peru, were built to 4 ft 8 1⁄2 in (1,435 mm) standard gauge. Ninety were built to 3 ft 6 in (1,067 mm) Cape gauge for a number of different African railways. For Spain, sixteen were built to 1,672 mm (5 ft 5 13⁄16 in) gauge.


2-8-2+2-8-2, Overview, Modified Fairlie locomotives
The South African Railways (SAR), where the Modified Fairlie concept was conceived as a possible alternative to the Garratt, was the only user. The Modified Fairlie was essentially an adaptation of the Kitson-Meyer concept. It was similar in appearance to a Garratt, but with the boiler, cab, coal and water bunkers all mounted on a single rigid frame which pivoted on the engine units, with the pivot centers located approximately at the centre of the rigid wheelbase of each engine unit. In the Garratt design, by comparison, the coal and water bunkers are mounted directly on the engine units and swivel with them, while the boiler, firebox and cab are mounted on a rigid frame which is suspended between the two engine units.


2-8-2+2-8-2, Usage, South Africa
Between 1925 and 1931, the SAR placed eighteen 3 ft 6 in (1,067 mm) Cape gauge Class GE Garratts in service, all built by BP between 1924 and 1930. The first six entered service in 1925 and proved so successful that a second order for ten was placed in 1926. Another two locomotives entered service in 1931. All of them had Belpaire fireboxes, plate frames, Walschaerts valve gear and were superheated.


2-8-2+2-8-2, Usage, South Africa
The locomotive was an enlargement of the Class GD 2-6-2+2-6-2 Double Prairie and was designed as a heavy goods locomotive for use on light 60 pounds per yard (30 kilograms per metre) rail. They were the first eight-coupled Garratts to be built for the SAR and, on a tractive effort basis at the time of their introduction, they were the most powerful locomotives operating on light track in Africa and the Southern Hemisphere.


2-8-2+2-8-2, Usage, South Africa
In 1927, the SAR placed ten Class HF Modified Fairlie Double Mikados in service, followed by an eleventh one in 1928. The locomotive was designed by the SAR under the direction of Colonel F.R. Collins DSO, SAR Chief Mechanical Engineer from 1922 to 1929, and was built by Henschel & Son in 1926 and 1927, hence the designation of Class HF for "Henschel Fairlie". Designed for mainline work, it was the Modified Fairlie equivalent of the Class GE Garratt which was similar in both size and mechanical respects. It had Walschaerts valve gear, a bar frame and was superheated, with a round-topped firebox.


2-8-2+2-8-2, Usage, South Africa
The Class HF proved to be a powerful locomotive, but it was less successful than its Garratt equivalent. The pivot bearings were subject to quite rapid wear since they carried a considerable additional load compared to those on the Garratt, as a result of the water and coal bunkers which were mounted on the main frame instead of on the engine units. This resulted in increased maintenance and, as a consequence, increased operating cost. No more locomotives of the Modified Fairlie design were acquired by the SAR.


2-8-4
Under the Whyte notation, a 2-8-4 is a steam locomotive that has two unpowered leading wheels, followed by eight coupled and powered  driving wheels, and four trailing wheels. This locomotive type is most often referred to as a Berkshire, though the Chesapeake and Ohio Railway used the name Kanawha for their 2-8-4s. In Europe, this wheel arrangement was mostly seen in mainline passenger express locomotives and, in certain countries, in tank locomotives.


2-8-4, Overview
In the United States of America, the 2-8-4 wheel arrangement was a further development of the enormously successful United States Railroad Administration (USRA) 2-8-2 Mikado. It resulted from the requirement for a locomotive with even greater steam heating capacity. To produce more steam, a solution was to increase the size of the locomotive's firebox, but the 2-8-2 wheel arrangement with its single axle trailing truck limited the permissible increased axle loading from a larger firebox. The most practical solution was to add a second trailing axle to spread the increased weight of a larger firebox.


2-8-4, Overview
The first American 2-8-4s were built for the Boston and Albany Railroad in 1925 by Lima Locomotive Works. The railroad's route across the Berkshire mountains was a substantial test for the new locomotives and, as a result, the name Berkshire was adopted for the locomotive type.


2-8-4, Overview
In Europe, 2-8-4 tender locomotives were designed mainly for passenger express trains, but they also hauled long distance express freights to increase utilisation. European 2-8-4 tank locomotives were a logical transition from the 2-8-2T locomotive types, allowing larger fireboxes and larger coal bunkers. They were mainly used for busy suburban services in heavily populated suburban areas of big cities, but infrequently also for sparsely populated rural areas or long distance lines.


2-8-4, Usage, Australia
The Western Australian K-class was a class of 2-8-4T steam locomotives of the Western Australian Government Railways (WAGR). Between 1893 and 1898, the WAGR took delivery of 24 of these locomotives from Neilson and Company. They entered service on the Eastern Railway between Midland Junction and Northam. In 1900, during the Second Boer War, the Imperial Military Railways experienced a shortage of locomotives and six more new K class locomotives destined for the WAGR  were diverted to South Africa, where they were known as the Western Australians.


2-8-4, Usage, Australia
The  South Australian Railways also operated 2-8-4s. Fleet construction commenced in 1930 and by the end of 1943, seventeen locomotives were in service on the 5 ft 3 in (1,600 mm) gauge system. The design of these locomotives was based on American practices. After they were withdrawn from service by 1958, they were all scrapped.


2-8-4, Usage, Austria
The heavy Class 214 1′’D2′ (2-8-4) two-cylinder simple expansion express passenger locomotive was developed in Austria in 1927. It was designed by engineers of the Floridsdorf Werke and was the largest Austrian steam locomotive and the most powerful Berkshire type to run in Europe. Designed for the West railway express train service, they were to be used to haul 580-ton express trains from Wien Westbahnhof in Vienna over 317 kilometres (197 miles) to Salzburg. This mainline has three approximately 11.3-kilometre long (7-mile) banks with gradients between 1 in 91 and 1 in 125.


2-8-4, Usage, Austria
Two prototypes were built, a two-cylinder and three-cylinder version. When tested, the two-cylinder version proved to be superior to the three-cylinder Class 114 version, and eventually twelve more two-cylinder Class 214 locomotives were built. In 1936, No. 214.13 reached a speed of 156 kilometres per hour (97 miles per hour), the highest speed ever attained by an Austrian steam locomotive. The regular speed limit was 120 kilometres per hour (75 miles per hour).


2-8-4, Usage, Austria
From 1938, the Deutsche Reichsbahn (DRB) designated the locomotive class 12.0. In the mid-1939, they hauled 600 tons express trains out of Vienna over Wienerwald at a speed of 65 kilometres per hour (40 miles per hour), reaching 120 kilometres per hour (75 miles per hour) over level stretches.


2-8-4, Usage, Austria
In 1945, seven of these locomotives were taken over by the Soviet Military Administration when they occupied the Russian Zone in Austria. These locomotives had "T" (Trofya) painted before their running numbers and were marked "CCCP". The Russians did not transfer these locomotives out of Austria and, when they withdrew their occupying forces in September 1955, the locomotives were returned to the Austrian Federal Railways (ÖBB).


2-8-4, Usage, Austria
When the mainline west of Vienna was electrified, all the ÖBB 1’D2’ locomotives were taken out of service and written off. On 15 February 1962, locomotive No. 12.10, built by Floridsdorf in 1936, was preserved as museum locomotive at the Eisenbahnmuseum Strasshof.


2-8-4, Usage, Brazil
Beyer Peacock delivered four 2-8-4T locomotives to Minas & Rio Railway (gauge 1000mm) in 1890, and one more in 1894.


2-8-4, Usage, Brazil
The French state-owned sales consortium Groupement d´Exportation de Locomotives en Sud-Amérique (GELSA) delivered 66 ultra-modern 2-8-4 two-cylinder simple expansion locomotives for the 1,000 mm (3 ft 3+3⁄8 in) metre gauge Brazilian Railways in 1951 and 1952. They were built by Société Francaise de Construction Mécaniques (Cail), Société des Forges et Ateliers de Creusot (Schneider of Le Creusot) and Compagnie de Fives-Lille. All were delivered to Brazil by the end of 1952.


2-8-4, Usage, Brazil
Designed under the direction of engineer André Chapelon, this class demonstrated that large and powerful steam locomotives could run in general use on light rails of 22 kilograms per metre (44 pounds per yard) with low speed limits. Their maximum axle load had been reduced to 10 tons, all were fitted with double Kylchap exhaust systems and their leading and trailing trucks had Athermos axle boxes. Three tender types could be coupled to them, one heavy and two light, for work in different areas.


2-8-4, Usage, Brazil
These modern locomotives were regarded with suspicion by some enginemen who were used to obsolete British locomotives which were often over forty years old. In addition, diesel locomotive salesmen claimed that steam traction was obsolete. This attitude spread to middle management staff, with the result that these modern French steam locomotives were replaced in the 1960s, when they were hardly run in. Some of those locomotives which worked in Southern Brazil were leased to the Bolivian Railways in the 1960s. By 2004, some still existed as wrecks in a locomotive dump near Santa Cruz in Bolivia.


2-8-4, Usage, Bulgaria
As part of their modernising and standardisation program, the Bulgarian State Railways (BDZ) ordered twenty superheated three-cylinder 2-8-4T (1’D2’-h3) locomotives from Krupp in 1941. The industrial disruption of the Second World War, however, overloaded the German locomotive builders with domestic production demands and Krupp was only able to produce ten of these new BDZ Class 36 tank locomotives in 1943, works numbers 2272 to 2281.


2-8-4, Usage, Bulgaria
The new 109.9 ton Class 36 locomotives were intended to replace the older 2-8-0 (1D-h2) locomotives on local passenger train services. The axle loading was kept below 16 tons and their large coal and water capacities made the new class suitable for a wider range of duties, if required. Small smoke deflectors were fitted to the top of the smokebox.


2-8-4, Usage, Bulgaria
When the new locomotives arrived in Bulgaria in 1943, they were allocated to Sofia depot. Between 1953 and 1957, five locomotives were relocated to Plovdiv depot to serve the Plovdiv-Svilengrad line. In addition to the local passenger train service, duties there also included international express trains to and from Turkey. In 1961, the remaining five locomotives were relocated from Sofia to Varna depot. They remained on these local passenger train duties well into the 1970s, when they were ousted by diesel locomotives and diesel trainsets. Some were preserved.


2-8-4, Usage, Canada
The Toronto, Hamilton and Buffalo Railway (TH&B) was the only Canadian Railway to operate 2-8-4 Berkshires. Only two locomotives were ordered from the Montreal Locomotive Works (MLW) in 1927, works numbers 67573 and 67574. They were the last new steam locomotives to be ordered by the TH&B and were allocated road numbers 201 and 202. They were fitted with Coffin feedwater heaters and duplex stokers, and had a working order weight of 128 tons.


2-8-4, Usage, Canada
After being equipped with Automatic Train Control (ATC) in 1929, they were the only TH&B freight locomotives which were allowed to run on New York Central’s tracks, on the Welland-Buffalo line. Due to dieselisation, both were withdrawn from service in June 1953. Both locomotives 201 and 202 were scrapped in late 1953 .


2-8-4, Usage, Czechoslovakia, Tank locomotives
The Czechoslovak State Railways (CSD) was one of the largest tank locomotive users in Europe. The dense railway network in Bohemia and Moravia provided the ideal environment for local short distance passenger train workings powered by numerous classes of tank locomotives. On 31 December 1937, the CSD had no less than 1,250 tank locomotives on its roster, of which 385 were eight-coupled tank locomotives.


2-8-4, Usage, Czechoslovakia, Tank locomotives
The first Czechoslovakian 1’D2’t-h2 (2-8-4) tank locomotive was derived from the CSD Class 455.1 1’D-h2 (2-8-0) tender locomotive, with water tanks, a coal bunker and a trailing bogie added. Apart from changing the drive from the second to the third coupled axle and increasing the superheating surface of the boiler, these handsome tank locomotives were mechanically identical to the tender locomotives. They were originally intended to be used on the 167-kilometre long (104-mile) Prague to České Budějovice (Böhmisch Budweis) line and on branch lines diverting from the mainline for local train service. At the time, however, the 16 ton axle load proved to be too high for most of the lines where they were intended to run and for this reason only 27 locomotives were built between 1928 and 1932.


2-8-4, Usage, Czechoslovakia, Tank locomotives
The first thirteen were initially designated Class 446.0, but an increase in their permitted maximum speed to 80 kilometres per hour (50 miles per hour) led to the locomotive's reclassification to Class 456.0, numbered 456.001 to 027. These were powerful tank locomotives, nicknamed Krasin after the explorer General Nobile who reached the North Pole in 1928. When tested while hauling a 900-ton train, one reached a maximum speed of 90 kilometres per hour (56 miles per hour) at level and an average speed of 32 kilometres per hour (20 miles per hour) while climbing a 1 in 100 gradient.


2-8-4, Usage, Czechoslovakia, Tank locomotives
Between 1938 and 1945, all of them remained on the Böhmisch-Mährisch Bahn (BMB) and Protektorátni Drahy Cech a Moravy (CMD) lines in Bohemia and Moravia, and all 27 survived the Second World War. By the early 1960s, the Class 456.0 locomotives were spread thinly over most of the country, having been allocated to locations from Plzeň in western Bohemia to Banská Bystrica in Slovakia. All were withdrawn from service between 1968 and 1972. One, no. 456.011, went into industrial service and three others, numbers 456.015, 024 and 026, were later used as mobile boilers. The remainder were scrapped.


2-8-4, Usage, Czechoslovakia, Tender locomotives
The CSD ordered three Class 486.1 1’D2’-h3 (2-8-4) locomotives, based on the three-cylinder Class 114 locomotive of the Austrian Federal Railways (BBÖ). This hand-fired locomotive had a Krauss-Helmholtz leading truck and the diameter of its coupled wheels was 1,830 millimetres (72 inches). Its total weight in working order was 107.6 tons, of which 63.9 tons were adhesive weight. All three cylinders were of 550 millimetres (21.65 inches) bore with a 680 millimetres (26.77 inches) stroke. The heating surface of the boiler was 253.2 square metres (2,725.42 square feet), of which 105.6 square metres (1,136.67 square feet) were superheating area. The grate area was 5 square metres (53.82 square feet) and the locomotive was designed for possible coal dust firing. They had Class 926.0 tenders, which were rebuilt from Class 623.0 tenders.


2-8-4, Usage, Czechoslovakia, Tender locomotives
They were not as successful as expected. One of the Class was tested against a Class 486.0 2’D1’-h3 (4-8-2) locomotive on the 248 kilometres (154 miles) hilly mainline between Žilina and Košice on the former Košice-Bohumín Drahy (KBD) line. It proved to be inferior to its opponent in both speed and power.


2-8-4, Usage, Czechoslovakia, Tender locomotives
All three locomotives were allocated to the Brno shed for most of their active service lives. During the years from 1938 to 1945, they were rostered as BMB-CMD locomotive stock. They were withdrawn from service in 1967 and 1968 and were later used as mobile boilers.


2-8-4, Usage, Germany, Deutsche Bundesbahn
After the Second World War, the recovering West Germany needed economical assistance. This came, in part, in the form of new locomotive orders placed with the West German locomotive industry, which kept it going in the tough and competitive world markets.


2-8-4, Usage, Germany, Deutsche Bundesbahn
A new tank locomotive type was designed by Krauss-Maffei and, in 1951, the firm built thirteen locomotives of a new Deutsche Bundesbahn (DB) Class 65 1’D2’t-h2 (2-8-4T) locomotive. Five more followed in 1955. In test, these locomotives hauled 800 tons on level track, while they managed to reach 50 kilometres per hour (31 miles per hour) hauling 400 tons up a 1 in 100 gradient. All the locomotives had small "Witte" type smoke deflectors. Their maximum speed was 85 kilometres per hour (53 miles per hour), even running bunker first.


2-8-4, Usage, Germany, Deutsche Bundesbahn
These locomotives saw service in local passenger train service around big cities and on branch lines which could bear the 17.5 ton axle load. They were found to be economical in service and served well during the short period they spent in service. In the late 1960s and early 1970s, they were ousted by expanding electrification and by diesel locomotives and diesel motor trainsets.


2-8-4, Usage, Germany, Deutsche Reichsbahn
The East German Deutsche Reichsbahn’s 1’D2’t-h2 (2-8-4T) locomotives were derived from the West German Class 65 and became the Class 65.10. They were capable of developing 1,500 indicated horsepower (1,100 kilowatts) and could run at 90 kilometres per hour (56 miles per hour) on level track, hauling 350 tons passenger trains. A total of 88 Class 65.10 locomotives were built between 1954 and 1957. These locomotives had the DR’s version of small "Witte" type smoke deflectors.


2-8-4, Usage, Germany, Deutsche Reichsbahn
These were the last new-built 1’D2’t-h2 (2-8-4T) 1,435 mm (4 ft 8+1⁄2 in) standard gauge locomotives in the world. Their maximum 17.5 ton axle load restricted them to mainline service. They were intended to haul heavy suburban trains around Berlin, Leipzig, Halle and Magdeburg, where they replaced the older Prussian T 12 and Prussian T 18 classes. Many were still in service in the 1970s and some still survived in the early 1980s.


2-8-4, Usage, Germany, Deutsche Reichsbahn
For branch line service, the DR designed a smaller wheeled version of the Class 65.10. This locomotive had only a 15-ton axle load and became the DR Class 83.10. Its maximum speed in both directions was 60 kilometres per hour (37 miles per hour). These locomotives were also fitted with the DR's version of "Witte" smoke deflectors, the only tank locomotive designed for freight service that had them.


2-8-4, Usage, Germany, Deutsche Reichsbahn
In 1955, 27 of these locomotives were built and used for working freight and mixed trains on short branch lines. They also worked on mountainous lines with sharp curves and steep gradients of more than 1.5% (1 in 67) and where 60 kilometres per hour (37 miles per hour) was the maximum speed limit.


2-8-4, Usage, Japan
The Japanese National Railways (JNR) closely followed American practice after the Second World War, with Berkshire locomotives used mainly on heavy freight service, such as heavy coal trains. They were the heaviest steam locomotives used on the JNR's 3 ft 6 in (1,067 mm) gauge lines.


2-8-4, Usage, Japan
The JNR rebuilt a total of 104 locomotives to the 2-8-4 wheel arrangement from its older 2-8-2 Mikado classes, the Class D50, Class D51 and Class D52.


2-8-4, Usage, Japan
Some of these locomotives survived in service up to the end of steam traction on the JNR in 1974.


2-8-4, Usage, Mexico
In 1951, Mexico's Ferrocarriles Nacionales de México (N de M) bought five 2-8-4 locomotives, built by Baldwin Locomotive Works in 1940, from Norfolk Southern Railway in the United States of America (USA), where they had become redundant due to dieselisation. Before their arrival in Mexico, all five went through a complete major overhaul in the USA. They arrived in Mexico late in 1951 and were allocated N de M numbers 3350 to 3354. Remaining in service until the late 1960s, they became the last USA-built Berkshires in the world to remain in revenue-earning common carrier service.


2-8-4, Usage, New Zealand
In 1904, the Wellington and Manawatu Railway Company (WMR) ordered a 2-8-4 tank locomotive from Baldwin Locomotive Works for banking duties on the 2+1⁄2% (1 in 40) gradients from Wellington to Ngaio. The locomotive, no. 3, was nicknamed Jumbo. When the New Zealand Government purchased the WMR, no. 3 was renumbered to WJ class no. 466 by the New Zealand Government Railways. It was the only locomotive in the class.


2-8-4, Usage, New Zealand
The locomotive had a tendency for cracking its bar frame on this heavy duty. By 1920, it was waiting to go to the Petone Works with yet another crack in the frame and it did not see much service after that. The solitary 2-8-4T locomotive in New Zealand was written off the books in 1928 and its boiler was sent to the Taumarunui locomotive depot for use as a washout boiler.


2-8-4, Usage, Norway
In the mid-1930s, the Norwegian State Railways (Norges Statsbaner or NSB) ordered altogether eighteen powerful superheated four-cylinder compound 1'D2'-h4v (2-8-4) passenger locomotives for express and passenger train service on its 553-kilometre long (344-mile) single mainline between Oslo and Trondheim, on the northern section between Otta and Trondheim.


2-8-4, Usage, Norway
The 210-kilometre long (130-mile) section of the mainline between Trondheim and Dombås reaches an altitude of 1,041 metres (3,415 feet) over the Dovrefjell, with gradients of 1 in 46 to 1 in 56 and curves of 200 to 300 metres (660 to 980 feet) radius. At the time, the maximum axle load was limited to 15.5 tons. Great skill was displayed in the design of these locomotives, which were built specifically to operate 300 ton trains under these conditions. Weight reduction was a major problem and, as a consequence, the frame was constructed of only 255-millimetre thick (10-inch) plate, but strongly braced, while the platform was of aluminium.


2-8-4, Usage, Norway
The planned eighteen NSB Class 49 locomotives never materialised, however, since those under construction at the Krupp Works in Essen, Germany, were damaged so severely by Allied bombing in October 1943 that they were never completed. In addition, Thune's Works at Skøyen in Norway could not carry on with the construction of its share of the order because of a wartime lack of high quality steel and other materials.


2-8-4, Usage, Norway
Only seven Class 49 locomotives were eventually placed in service. Of these, three were built by Hamar and Thune in 1935 and 1936, two by Krupp in 1940 and two by Thune in 1941. These locomotives, nicknamed Dovregubben (Dovre Giants), were the only true compounds owned by the NSB.


2-8-4, Usage, Norway
On test, one of them hauled 350 tons at 60 kilometres per hour (37 miles per hour) up a gradient of 1 in 55, developing 2,650 indicated horsepower (1,980 kilowatts). Despite the relatively small 1,530 millimetres (60.24 inches) diameter coupled wheels, a speed of 115 kilometres per hour (71 miles per hour) was reached with the same load on level track.


2-8-4, Usage, Norway
In normal service, their maximum speed was restricted to 80 kilometres per hour (50 miles per hour) on account of the light track in use at the time and they were capable of hauling 280 tons at 60 kilometres per hour (37 miles per hour) up long 1 in 55 gradients.


2-8-4, Usage, Norway
When compared to other NSB steam locomotives, these engines had a short lifespan and all were written off in 1958, after the arrival of class Di3 diesel locomotives on the Dovre line.


2-8-4, Usage, Romania
When the Romanians looked for a powerful passenger locomotive to serve on the Căile Ferate Române (CFR) mainlines across the Carpathian Mountains, they decided upon the Austrian Federal Railways (BBÖ) Class 214. They purchased the drawings from Austria and 79 locomotives of the same type were built under licence in their modern new Malaxa and Reşiţa Works in Romania. These 2-8-4 locomotives entered service as CFR class 142.000. In 1939, a batch was built with Caprotti instead of Lentz poppet valves, but since some of these were later observed with Lentz valve gear, the Italian gear had presumably been removed.


2-8-4, Usage, Romania
These locomotives proved to be suitable for Romanian conditions, being of ample dimensions, moderate axle load, straightforward two-cylinder engines of 650 millimetres (25.59 inches) bore with a 720 millimetres (28.35 inches) stroke, and 1,940 millimetres (76.38 inches) diameter coupled wheels. The total weight in working order was 123.5 tons, of which 72.1 tons was adhesive weight.


2-8-4, Usage, Romania
Nearly all of them were still in service in the late 1960s. The Class 142 locomotives hauled the principal CFR express trains on mainlines and, like their Austrian cousins, were able to render good performance. At least three have been preserved for museums, locomotives no. 142.008, 142.044 and 142.072.


2-8-4, Usage, South Africa
In 1900, during the Second Boer War, the Imperial Military Railways experienced a shortage of locomotives and six K class Berkshire tank locomotives, destined for the Western Australian Government Railways, were diverted to South Africa where they were known as the Western Australians.


2-8-4, Usage, South Africa
In 1902, they came onto the roster of the Central South African Railways and were designated CSAR Class C. By 1912, when the renumbering onto the South African Railways (SAR) roster was implemented, these locomotives were considered obsolete and were not included in the SAR classification and renumbering list, but recommended for scrapping even though they were still less than twelve years old.


2-8-4, Usage, South Africa
In 1949 and 1950, the SAR placed 100 Class 24 Berkshires in branch line service, which included the whole of South West Africa (Namibia). They were acquired to replace the ageing fleet of Class 6 and Class 7 locomotives on light 45 pounds per yard (22 kilograms per metre) rail.


2-8-4, Usage, South Africa
The locomotive was designed by Dr. M.M. Loubser, Chief Mechanical Engineer of the SAR from 1939 to 1949. It had a one-piece steel main frame that was cast integrally with the cylinders, including the cylinder hind covers, smokebox support frame, stays and various brackets, all of which would normally be separate items riveted or bolted onto the frame. Advantages of this arrangement were reduced maintenance and less time spent in shops. It was the first South African steam locomotive to be built using this technique. They were built with Watson Standard no. 1 boilers and they used Type MY Torpedo tenders that ran on three-axle Buckeye bogies.


2-8-4, Usage, South Africa
It was the only Berkshire type to see service on the SAR. Most of them went to South West Africa, where 55 of them would remain in operation until strengthening of the track and the introduction of diesel traction made them available to be employed elsewhere. They were withdrawn in the mid-1980s. Several have been preserved in running order for service on excursion trains, operated by private steam enthusiast groups in Cape Town and in Gauteng.


2-8-4, Usage, Soviet Union
From the mid-1930s until their replacement by diesel locomotives, the 2-8-4 (1’D2’-h2) wheel arrangement was relatively common in the former Soviet Union. When built, these locomotives were designated Class IS, for Josif Stalin. The Class IS locomotive was a passenger derivative of the Class FD 1’E1’-h2 (2-10-2) freight locomotive and had many parts in common with the Class FD.


2-8-4, Usage, Soviet Union
The Soviet 2-8-4 was the most numerous single Berkshire class built in the world. Kolomna Locomotive Works built the first four locomotives. In 1935, production was transferred to the enlarged and modernised former Luhansk Works which was renamed Voroshilovgrad Locomotive Works. A total of 649 locomotives of the two variants, Class IS20 and Class IS21 (later Class FDp), were built between 1932 and 1942. After Germany attacked the Soviet Union on 22 June 1941, the Russians evacuated all semi-completed class IS21 locomotives from Voroshilovgrad. The Ulan-Ude Locomotive Works completed the last eleven in 1941 and 1942.


2-8-4, Usage, Soviet Union
Despite their moderate size compared to American and Canadian-built 2-8-4s, the Soviet 2-8-4 was a good example of a Berkshire type designed for heavy express and passenger train service. It had a 7.04 square metres (75.78 square feet) grate, 15 kilograms per square centimetre (213 pounds per square inch) boiler pressure, 295.2 square metres (3,178 square feet) boiler heating surface of which 148.4 square metres (1,597 square feet) was superheated, and only 20 to 21 tons maximum axle load.


2-8-4, Usage, Soviet Union
Their 1,850 millimetres (72.83 inches) diameter coupled wheels and cylinders of 670 millimetres (26.38 inches) bore and 770 millimetres (30.31 inches) stroke, with a total weight of 133 tonnes of which 80.7 tonnes were adhesive weight, enabled the locomotives to easily reach the maximum permitted speed of 120 kilometres per hour (75 miles per hour) with 700 to 800 tons behind the tender. The usual maximum speed was about 100 kilometres per hour (62 miles per hour), with an occasional need of 115 kilometres per hour (71 miles per hour).


2-8-4, Usage, Soviet Union
They were used as express passenger locomotives on mainlines which had type Ia rails of 43.5 kilograms per metre (88 pounds per yard). They were later reclassified as Class FDp (FD passenger). One locomotive, no. IS20-16, was streamlined and achieved a speed of 155 kilometres per hour (96 miles per hour) during test runs in 1937. Another, no. IS20-241, was displayed at the Paris World Exhibition in 1937, where it demonstrated the Soviet Union's locomotive production.


2-8-4, Usage, Soviet Union
The first four were initially allocated to the October Railway and ran between Moscow and Leningrad, hauling heavy night passenger trains. Later, when the line was upgraded with heavier rails, they were transferred to the Moscow-Kursk-Kharkov-Sinelnikovo line. When more class IS locomotives began to roll out from the Voroshilovgrad production lines, they were used on the upgraded Moscow-Smolensk-Minsk, Moscow to Valuiki and Mitchurinsk to Rostov-on-Don mainlines.


2-8-4, Usage, Soviet Union
Only one such locomotive was preserved, no. IS21-578, plinthed outside the main railway station in Kyiv in Ukraine.


2-8-4, Usage, United States
Locomotives of a 2-8-4 wheel arrangement were used mainly for hauling fast express freight trains on heavy freight service. They often replaced older 2-8-2 Mikados where more power was required. In turn, they were often replaced by even more powerful 2-10-4 Texas type locomotives.


2-8-4, Usage, United States
Six years after the Atchison, Topeka and Santa Fe Railway experimented with the first 2-10-4, the first 2-8-4s were built for the Boston & Albany (B&A) by Lima Locomotive Works in 1925. The railroad's route over the Berkshires was a substantial test for the new locomotives, but the type proved its worth, outpacing the 2-8-2 Mikados already in use there. This mountain range lent its name to the locomotive type, though the Chesapeake and Ohio Railway preferred the name Kanawha for their 2-8-4s. Buoyed by the success of the demonstrations on the B&A, Lima and ALCO both sold a few hundred of the new locomotive type.


2-8-4, Usage, United States
The Berkshire type's big boost came in 1934, when the New York, Chicago and St. Louis Railroad (Nickel Plate Road or NKP) received its first 2-8-4s, built to a new design from the Advisory Mechanical Committee (AMC) of the Van Sweringen empire. Under the Van Sweringen umbrella were the Nickel Plate Road, Erie Railroad, Chesapeake and Ohio Railway and Pere Marquette Railway. The AMC's design generated 64,100 pounds-force (285 kilonewtons) of tractive effort and became the standard design for subsequent Berkshires. The Erie Railroad purchased the largest number of 2-8-4s, rostering 105.


2-8-4, Usage, United States
Lima's last steam locomotive was also the last American 2-8-4, the NKP's No. 779 of 1949. Some 700 2-8-4s were built for American service, constituting 2% of the steam fleet prior to dieselization and delivering 5% of the nation's freight ton-miles.


2-8-4, Usage, United States
As the first large scale user, the NKP became synonymous with the Berkshire locomotive type. One of this class, Nickel Plate Road no. 765, is preserved in operating condition and is operated occasionally from its New Haven, Indiana home. Nickel Plate Road no. 779 is preserved as a static display in Lincoln Park in Lima, Ohio.


2-8-4, Usage, United States
Many larger American railroads rostered Berkshires. The table lists data on the American locomotives as they were built.


2-8-4, Berkshires in fiction
In the motion picture The Polar Express, the "know-it-all" boy identifies the train's locomotive as a Baldwin 2-8-4 built in 1931, although the actual prototype for the film's locomotive was the Pere Marquette no. 1225, a Berkshire built by the Lima Locomotive Works in 1941.


2-8-4, Berkshires in fiction
In the Transformers television series, motion picture and toy line, the Decepticon triple changer Astrotrain is modeled on a Japanese Class D62 2-8-4 locomotive.


2-8-4, Berkshires in fiction
Locomon in the motion picture Digimon: Runaway Locomon is a 2-8-4 type locomotive.


2-8-6
In the Whyte notation for describing steam locomotive wheel arrangement, a 2-8-6 is a locomotive with a two-wheel leading truck, eight driving wheels, and a six-wheel trailing truck. All 2-8-6 locomotives constructed have been 2-8-6T tank locomotives of the Mason Bogie pattern.


2-8-6
Other equivalent classifications are:UIC classification: 1D3 (also known as German classification and Italian classification)French classification: 143Turkish classification: 48Swiss classification: 4/8


2-8-6
In the UIC classification as applied in Germany and Italy, a rigid-framed locomotive of this arrangement would be 1'D3', and the Mason bogie (1'D)'3'.


2-8-6
Four Mason Bogies of this type were built for the Denver, South Park and Pacific Railroad; #25 Alpine, #26 Rico, #27 Roaring Fork and #28 Denver. They were narrow gauge locomotives of 3 ft (914 mm) gauge. Two more went to the Denver, Utah and Pacific, #10 Middle Park and #19 Denver. The DU&P sold one of the latter to the Burlington and Northwestern Railway, a narrow-gauge affiliate of the CB&Q operating in Iowa.


2-8-8-0
In the Whyte notation for the classification of steam locomotives by wheel arrangement, a 2-8-8-0 is a locomotive with a two-wheel leading truck, two sets of eight driving wheels, and no trailing truck.


2-8-8-0, Equivalent classifications
The UIC classification is refined to (1'D)D for Mallet locomotives.


2-8-8-0, Examples
The Great Northern Railway used the 2-8-8-0s as their N-1's which were built by Baldwin in 1912. They were rebuilt by GN in 1932 as a N-2, and later re-rebuilt in 1940 as an N-3, The locomotives, after their third rebuild into a N-3, had a larger boiler and bigger tender. The N-3's served on the GN for a collective 45 years (including previous service lives as N-1 and N-2 classes), in use until retired in 1957. The Union Pacific Railroad also operated this type; it was called the "Bull Moose" by Union Pacific crews.


2-8-8-0, Examples
The Union Pacific Bull Moose 2-8-8-0s were built in 1918 and 1924 by ALCO-Brooks. The Bull Moose Locomotives were used to haul heavy loads over Sherman Hill on the UP, the locomotives were most likely retired in the late 1940s to early 1950s because of slow speeds on freight, hauling at 12 miles an hour. The 9000 class of the Union Pacific can pull the same weight at 50 miles an hour. None of the Union Pacific Bull Moose Locomotives survived into preservation.


2-8-8-0, Examples
An example of one is Union Pacific #3559, was built July 1924 by ALCO-Brooks and retired in October 1953 Possibly scrapped in 1954. Out east, the Reading Railroad had 2-8-8-0s for coal switching on Steep Hills, also known as the Reading N-1, and the Baltimore and Ohio operated this type, with the B&O owning dozens of examples, most notably the EL-3 class. They were retired by the early 1950s. In the Midwest, the Kansas City Southern was a principal user of this configuration.


2-8-8-0, Examples
The Atchison, Topeka and Santa Fe Railway was the first to use the configuration. In 1911, their own workshop took a pair of standard 2-8-0 and combined them into a 2-8-8-0 "Consolidation Mallet" articulated locomotive. Four examples were built, but were never entirely satisfactory and were converted back to 2-8-0 in 1923. The first 2-8-8-0 operated by Baltimore and Ohio was numbered EL-1/a, which was built in 1916 at Baldwin Locomotive Works.


2-8-8-0, Examples
The western end of their network had ruling gradients greater than 2%, and the 2-8-8-0 offered exceptional tractive effort, enabling a single locomotive to move the heaviest freight trains. As well as building these locomotives from scratch, the last in 1920, ten were converted from 0-8-8-0 configuration in 1920 and a further ten from 2-8-8-2 in 1922. These locomotives remained in operation until after World War II, the last being withdrawn in 1955. None have been preserved.


2-8-8-0, Examples
One tender from the 2-8-8-0 #759 of the Kansas City Southern Railroad has been preserved, while the locomotive was scrapped. It is now preserved at the Illinois Railway Museum.


2-8-8-2
A 2-8-8-2, in the Whyte notation for describing steam locomotive wheel arrangements, is an articulated locomotive with a two-wheel leading truck, two sets of eight driving wheels, and a two-wheel trailing truck. The equivalent UIC classification is, refined to Mallet locomotives, (1'D)D1'. These locomotives usually employ the Mallet principles of articulation—with the rear engine rigidly attached to the boiler and the front engine free to rotate—and compounding. The 2-8-8-2 was a design largely limited to American locomotive builders. The last 2-8-8-2 was retired in 1962 from the N&W's roster, 2 years past the ending of steam though steam was still used on steel mill lines and other railroads until 1983.


2-8-8-2
Other equivalent classifications are:UIC classification: 1DD1 (also known as German classification and Italian classification)French classification: 140+041Turkish classification: 45+45Swiss classification: 4/5+4/5


2-8-8-2
The first 2-8-8-2 was built in 1909 by Baldwin, who sold two to the Southern Pacific Railroad (classified MC-1), and then three each to the Union Pacific Railroad and UP-owned Oregon Railroad and Navigation Company. Baldwin conceived the type as an expansion of the 2-6-6-2 permitting a greater tractive effort.


2-8-8-2
The next order for the type was from the Southern Pacific; these differed in being cab forward locomotives, so that the crew could have better visibility and breathing in the SP's long tunnels and snow sheds. They were very successful, and SP continued to order cab-forward locomotives, building an eventual fleet of 256 of numerous classes; later cab-forwards were 4-6-6-2s (originally 2-6-6-2s) and 4-8-8-2s.


2-8-8-2
The 2-8-8-2 proved itself to be a capable hauler on mountain grades, enabling the replacement of several smaller locomotives and hauling longer trains than before. Most of them were not fast; they hauled at drag freight speeds, up to 25 mph (40 km/h). However, the Norfolk & Western Y6 class were designed to run up to 55 mph (89 km/h). The locomotives were adopted by a broad spectrum of mountain railroads, including the Norfolk & Western, Southern, Virginian, Great Northern, Clinchfield, Denver & Rio Grande, Reading, Western Maryland, Missouri Pacific, Frisco, and the Duluth, Missabe and Iron Range Railway.


2-8-8-2
On many railroads, the locomotives of the type were the most powerful on the roster. When built, the 2-8-8-2s of the Western Pacific Railroad were among the most powerful steam locomotives in the world and formed the basis for the later 2-8-8-4 "Yellowstone" type engines used by the Duluth, Missabe and Iron Range.


2-8-8-2
The last compound Mallet locomotives to operate on major railroads in the United States were the 2-8-8-2 Y6b class of the Norfolk and Western Railway. After their final modifications in the 1950s, they were said to be capable of 170,000 lbs tractive effort in simple-expansion mode, although some have questioned this claim (the original design tractive effort was 152,206 lbs SIMPLE and 126,838 lbs COMPOUND). The last were retired in May 1960.


2-8-8-2
As of 2008, there are two surviving 2-8-8-2 locomotives, both former Norfolk & Western. N&W 2050 is from the railroad's Y3a class; Alco's Richmond works built it in 1923 and it is displayed at the Illinois Railway Museum in Union, Illinois. N&W 2156 is from the railroad's Y6a class; N&W's own Roanoke Shops built it in 1942 and it is owned by the Museum of Transportation in St. Louis, Missouri. The 2156 was displayed at the Virginia Museum of Transportation in Roanoke, Virginia from 2015-2020. As of June 2020, it has returned to the Museum of Transportation in St. Louis. It is also the strongest pulling extant steam locomotive in the world.


2-8-8-4
A 2-8-8-4 steam locomotive, under the Whyte notation, has two leading wheels, two sets of eight driving wheels, and a four-wheel trailing truck. The type was generally named the Yellowstone, a name given it by the first owner, the Northern Pacific Railway, whose lines run near Yellowstone National Park. Seventy-two Yellowstone-type locomotives were built for four U.S. railroads.


2-8-8-4
The equivalent UIC classification is, refined for Mallet locomotives, (1′D)D2′.


2-8-8-4
A locomotive of this length must be an articulated locomotive. All Yellowstones had fairly small drivers of 63 to 64 inches (1.60 to 1.63 m). (For greater speeds, the Union Pacific Railroad chose a four-wheel leading truck and drivers of 68 inches (1.73 m) for its Big Boy 4-8-8-4 class.)


2-8-8-4
Several classes of Yellowstone, especially the Duluth, Missabe and Iron Range's locomotives, are among the largest steam locomotives, with the exact ranking depending on the criteria used.


2-8-8-4, Northern Pacific
The Northern Pacific Railway was the first railroad to order a 2-8-8-4. The first was built in 1928 by American Locomotive Company; at the time, it was the largest locomotive ever built. It had the largest firebox ever applied to a steam locomotive, some 182 square feet (16.9 m2) in area, to burn Rosebud coal, a cheap low-quality coal. But the firebed was too large for the available draft and the fire burned poorly and developed under 5,000 horsepower. The problem was mitigated by blocking off the first few feet of the grates. Baldwin Locomotive Works built 11 more for the Northern Pacific in 1930. None were saved.


2-8-8-4, Southern Pacific
The Southern Pacific Railroad's famous "cab forward" articulated steam locomotives were effectively a Yellowstone in reverse. This was done to spare the crew from the heavy smoke output of the large engines on the former Central Pacific, where tunnels and snow sheds were common and lengthy. One is on display at the California State Railroad Museum in Sacramento. The ready availability of fuel oil in California made them possible. The SP also owned some conventional 2-8-8-4s for use in areas where coal was plentiful and snow sheds were rare. Lima Locomotive Works built 12 AC-9 class locomotives in 1939; they had skyline casings with striped pilots. At first, they burned coal but were later converted to oil. None were saved.


2-8-8-4, Duluth, Missabe and Iron Range
The Duluth, Missabe and Iron Range Railway hauled iron ore in Minnesota. Iron ore is heavy and the DM&IR operated long trains of ore cars, requiring maximum power. These locomotives were based upon ten 2-8-8-2s that Baldwin had built in the 1930s for the Western Pacific Railroad. The need for a larger, coal-burning firebox and a longer, all-weather cab led to the use of a four-wheel trailing truck, giving them the "Yellowstone" wheel arrangement. They were the most powerful Yellowstones built, producing 140,000 lbf (620 kN) of tractive effort, and had the most weight on drivers so that they were less prone to slipping.


2-8-8-4, Duluth, Missabe and Iron Range
Eight locomotives (class M-3) were built by Baldwin in 1941. The Yellowstones met or exceeded the DM&IR specifications, so 10 more were ordered (class M-4). The second batch was completed in late 1943 after the Missabe's seasonal downturn in ore traffic, so some of the new M-4s were leased to and delivered directly to the Denver & Rio Grande Western.


2-8-8-4, Duluth, Missabe and Iron Range
The next winter, the D&RGW again leased the DM&IR's Yellowstones as helpers over Tennessee Pass, Colorado, and for other freight duties. The Rio Grande returned the Yellowstones after air-brake failure caused No. 224 to wreck on the Fireclay Loop. This was despite the Rio Grande's earlier assessment that these Yellowstones were the finest engines ever to operate there.


2-8-8-4, Duluth, Missabe and Iron Range
DM&IRs were the only Yellowstones to have a high-capacity pedestal or centipede tender, and had roller bearings on all axles. Some of the locomotives had a cylindrical Elesco feedwater heater ahead of the smoke stack, while others had a Worthington unit with its rectangular box in the same location.


2-8-8-4, Duluth, Missabe and Iron Range
Only one Yellowstone was retired before dieselization took place on the Missabe; No. 237 was sold for scrap after a wreck. The rest of the 2-8-8-4s were retired between 1958 and 1963 as diesel locomotives took over.


2-8-8-4, Duluth, Missabe and Iron Range
Of the eighteen built, three survive and are on display in Minnesota: No. 225 at Proctor, No. 227 at the Lake Superior Railroad Museum in Duluth and No. 229 at Two Harbors.


2-8-8-4, Baltimore and Ohio
When the U.S. entered World War II The American railroads saw increases in traffic. The Baltimore and Ohio Railroad, along with other railroads, wanted to purchase more of the diesel locomotives since they were showing improved performance over steam locomotives. But the War Production Board regulated the production of steam and diesel locomotives until the war emergency was over.


2-8-8-4, Baltimore and Ohio
So along with producing 40 new class T-3 4-8-2 type locomotives built in-house at their Mt. Clare shops in Baltimore, Maryland, the B&O took delivery of 30 class EM-1 Yellowstones in 1944 and 1945, the largest number and the smallest of this type built by Baldwin as well as the most modern.


2-8-8-4, Baltimore and Ohio
The EM-1 produced 115,000 pounds-force (510 kN) of tractive effort on 64-inch (1.6 m) drivers with 235 pounds per square inch (1.62 MPa) steam pressure and four 24-by-32-inch (0.61 by 0.81 m) cylinders. The tender carried 22,000 US gallons (83 m3) of water and 25 tons of coal. The engine weighed 627,000 pounds (284 t) while the tender weighed 328,000 pounds (149 t) for a combined 1,010,700 pounds (458.4 t). Nothing bigger could operate within the tunnel clearances and track restrictions on the B&O's main line.


2-8-8-4, Baltimore and Ohio
They were equipped with the newest technology including the Worthington feedwater heater, superheater with front-end throttle, Cyclone front end, thermic syphons, a lateral cushioning device in the front pair of drivers on both engines and the front wheels and the trailing truck, as well as roller bearings on all axles, engine and tender, which gave them the reputation of "yard creepers", because three men could move one on a level track with the cylinder cocks open.


2-8-8-4, Baltimore and Ohio
B&O's president, Roy B. White, after inspecting the first one delivered, said to the general superintendent of motive power and equipment, A.K. Galloway, "Well, I must say, they have everything!"


2-8-8-4, Baltimore and Ohio
Fleet numbers 7600–7619 were built and delivered in 1944 and 7620–7629 in 1945, all by the Baldwin Locomotive Works of Philadelphia, Pennsylvania. They went to work on the Cumberland Division's rugged West End subdivision with its more than 2% grades and tight curves, where with the older 2-8-8-0 EL classes, they hauled West Virginia coal and freights. Since the EM-1s had roller bearings throughout, they also handled mail and express trains, replacing two B&O class T-3 4-8-2 Mountains.


2-8-8-4, Baltimore and Ohio
That continued until January 21, 1947, when near Oakland, Maryland, train 29 with engine 7625 derailed with the locomotive rolling onto the engineer's side, killing the engineer. The EM-1s were then restricted to coal and freight trains until the late 1950s, when the B&O used EM-1 No. 7600 for railfan trips.


2-8-8-4, Baltimore and Ohio
The EM-1s also ran on the Pittsburgh Division over Sand Patch Grade near Meyersdale, Pennsylvania, with empty hoppers, iron ore or dolomite loads westbound, coal eastbound, as well as general freight in both directions. In the late 1950s, the B&O used EM-1 No. 7600 for railfan trips mostly between Cumberland, MD, and Connellsville, PA. Well-known photographer and Cumberland, MD, native William P. Price captured on still pictures and 8mm films, the EM-1s on the east side of Sand Patch pulling heavy trains with two of the B&O's 2-10-2 class S1 and S1a Big Sixes on the rear as helpers dispatched from Hyndman, PA.


2-8-8-4, Baltimore and Ohio
Near the end of steam they were all sent out to Fairmont and Wheeling, West Virginia, and Lorain, Ohio, with lake-bound coal trains as well as runs between Willard, OH and Garrett, Indiana, until the B&O started to retire them in 1957, and almost all of them were scrapped.


2-8-8-4, Baltimore and Ohio
But one locomotive, No. 659, almost made it to preservation. The B&O Railroad Museum in Baltimore selected this locomotive as one of their future museum exhibits. However, there was a mix-up in communication, regarding the locomotive's status, and the salvage crew scrapped No. 659 where it stood. Now, none of the EM-1s survive today.


2-8-8-4, Outside the United States
The metre gauge Central Railway of Brazil took delivery of four 2-8-8-4s from the German firm of Henschel in 1937. They were the only narrow gauge locomotives of this wheel arrangement. They had the largest boilers ever used on a narrow-gauge simple expansion locomotive.


2-8-8-4, Outside the United States
Soviet Russia constructed two 2-8-8-4 locomotives at the Kolomna Locomotive Works. These were the P38 Class numbers P38.001 and P38.002. The first locomotive carried partial casings over the boiler and smokebox typical of the 1950s. P38.002 bore no such adornments and had a more conventional appearance. Both engines had tenders with part bogie and part fixed frame similar to the American 'centipede' tenders.


2-8-8-8-4
Under the Whyte notation for the classification of steam locomotives, a 2-8-8-8-4 has two leading wheels, three sets of eight driving wheels, and four trailing wheels.


2-8-8-8-4
Other equivalent classifications are:UIC classification: 1DDD2 (also known as German classification and Italian classification)French classification: 140+040+042Turkish classification: 45+44+46Swiss classification: 4/5+4/4+4/6


2-8-8-8-4
The equivalent UIC classification is to be refined to (1'D)D(D2') for these engines.


2-8-8-8-4
Only one 2-8-8-8-4 was ever built, a Mallet-type for the Virginian Railway in 1916. Built by Baldwin Locomotive Works, it became the only example of their class XA, so named due to the experimental nature of the locomotive. Like the same railroad's large articulated electrics and the Erie Railroad 2-8-8-8-2s, it was nicknamed "Triplex".


2-8-8-8-4
An overview of Triplex engineering is given at Triplex (locomotive).


2-8-8-8-4
The XA was unable to sustain a speed greater than five miles an hour, since the six cylinders could easily consume more steam than the boiler could produce. When operating in compound the high pressure steam was divided between the cylinders of the center engine. The exhaust from one cylinder was piped to the front articulated engine. The exhaust from the other center engine cylinder was piped to the tender engine.


2-8-8-8-4
The exhaust from the front engine was piped to the exhaust nozzle inside the firebox to generate draft through the firebox, through the fire tubes and out the exhaust stack. The exhaust from the tender engine went out of a stack at the rear of the tender water tank. Unfortunately it did not contribute to draft, being wasted. The tender had a four-wheel truck at the rear to help guide the locomotive into curves when drifting back downhill after pushing a train over the hill.


2-8-8-8-4
The XA was sent back to Baldwin in 1920 and was rebuilt as two locomotives, a 2-8-8-0,and a 2-8-2. Unlike their predecessor which lasted only a few years in service, these two locomotives remained in service until 1953. However, neither of the two locomotives were preserved.


2-Acetyl-1-pyrroline
2-Acetyl-1-pyrroline (2AP) is an aroma compound and flavor that gives freshly baked bread, jasmine rice and basmati rice, the spice pandan (Pandanus amaryllifolius), and bread flowers (Vallaris glabra) their customary smell. Many observers describe the smell as similar to "hot, buttered popcorn", and it is credited for lending this odor to the scent of binturong (bearcat) urine. Fresh marking fluid (MF) and urine of the tiger (Indian, Amur or Siberian) and Indian leopard also have a strong aroma due to 2AP.


2-Acetyl-1-pyrroline
2AP and its structural homolog, 6-acetyl-2,3,4,5-tetrahydropyridine of similar smell, can be formed by Maillard reactions during heating of food such as the baking of bread dough. Both compounds have odor thresholds below 0.06 ng/L.


2-Acetyl-1-pyrroline, Structure and properties
2AP is a substituted pyrroline and a cyclic imine as well as a ketone.


2-Acetyl-5-methylfuran
2-Acetyl-5-methylfuran is an organic compound with the chemical formula C7H8O2.


2-Acetylaminofluorene
2-Acetylaminofluorene (AAF, 2-AAF) is a carcinogenic and mutagenic derivative of fluorene. It is used as a biochemical tool in the study of carcinogenesis. It induces tumors in a number of species in the liver, bladder and kidney. The metabolism of this compound in the body by means of biotransformation reactions is the key to its carcinogenicity. 2-AAF is a substrate for cytochrome P-450 (CYP) enzyme, which is a part of a super family found in almost all organisms. This reaction results in the formation of hydroxyacetylaminofluorene which is a proximal carcinogen and is more potent than the parent molecule.


2-Acetylaminofluorene
The N-hydroxy metabolite undergoes several enzymatic and non-enzymatic rearrangements. It can be O-acetylated by cytosolic N-acetyltransferase enzyme to yield N-acetyl-N-acetoxyaminofluorene. This intermediate can spontaneously rearrange to form the arylamidonium ion and a carbonium ion which can interact directly with DNA to produce DNA adducts. In addition to esterification by acetylation, the N-hydroxy derivative can be O-sulfated by cytosolic sulfur transferase enzyme giving rise to the N-acetyl-N-sulfoxy product.


2-Acetylaminofluorene
In addition, the cytosolic N,O-aryl hydroxamic acid acyltransferase enzyme catalyzes the transfer of the acetyl group from the N atom of the N-OH-2-AAF to the O atom of the N-OH group to produce N-acetoxy-2-aminofluorene (N-OH-2-AF). This reactive metabolite spontaneously decomposes to form a nitrenium ion which will also react with DNA. However, the product of this latter reaction is the deacetylated aminofluorene adduct. The interconversion of amide and amine metabolites of 2-AAF can further occur via the microsomal enzyme deacetylase producing the N-hydroxy metabolite of the amine derivative.


2-Acetylaminofluorene
Subsequent esterification of the aryl hydroxylamine by sulfur transferase yields the sulfate ester which also spontaneously decompose to form nitrenium ion. The reactive nitrenium, carbonium and arylamidonium ion metabolites of 2-AAF react with the nucleophilic groups in DNA, proteins and endogenous thiols like glutathione. Other metabolites such as the N,O-glucuronide, although not directly activated products, can be important in the carcinogenic process because they are capable of degradation to proximal N-hydroxy metabolites. This metabolite is presumed to be involved in formation of bladder tumors. The mechanism for this is thought to involve degradation of glucuronide in the bladder due to acidic pH of urine.


2-Acetylfuran
2-Acetylfuran is a low melting solid or high boiling liquid, depending on temperature. The solid melts at 30 °C and has a density of 1.0975 g/ml at 20 °C, while the normal boiling point of the liquid is 168–169 °C. 2-Acetylfuran is a useful intermediate in the synthesis of fine chemicals and pharmaceuticals, and is used in the production of the generic cephalophosphorin antibiotic cefuroxime.


2-Acetylfuran, Synthesis
2-Acetylfuran was prepared by Ashina in 1914 via the reaction of the methyl Grignard reagent on 2-furonitrile. Modern industrial synthesis generally involves the Friedel–Crafts acylation of furan with acetic anhydride.


2-Acetylfuran, Applications, Pharmaceuticals
A one-pot synthesis of  an intermediate to the HIV integrase inhibitor S-1360 was based on the Friedel-Crafts alkylation of 2-acetylfuran with 4-fluorobenzyl chloride using zinc chloride catalyst.


2-Acetylfuran, Applications, Pharmaceuticals
Reaction of 2-acetylfuran with aqueous sodium nitrite gave 2-furanyloxoacetic acid, an intermediate to Cefuroxime, a second-generation cephalosporin antibiotic.


2-Acetylpyridine
2-Acetylpyridine is an organic compound with the formula CH3COC5H4N. It is a viscous colorless liquid that is widely used as a flavoring substance. It is found in malt and produced by the Maillard reaction and by nixtamalization. It contributes to the flavor of corn tortillas, popcorn, and beer.


2-Acetylpyridine
The compound is prepared by acylation of 2-bromopyridine via the Grignard reagent.


2-Acrylamido-2-methylpropane sulfonic acid
2-Acrylamido-2-methylpropane sulfonic acid (AMPS) was a Trademark name by The Lubrizol Corporation. It is a reactive, hydrophilic, sulfonic acid acrylic monomer used to alter the chemical properties of wide variety of anionic polymers. In the 1970s, the earliest patents using this monomer were filed for acrylic fiber manufacturing. Today, there are over several thousands patents and publications involving use of AMPS in many areas including water treatment, oil field, construction chemicals, hydrogels for medical applications, personal care products, emulsion coatings, adhesives, and rheology modifiers.


2-Acrylamido-2-methylpropane sulfonic acid, Production
AMPS is made by the Ritter reaction of acrylonitrile and isobutylene in the presence of sulfuric acid and water. The recent patent literature describes batch and continuous processes that produce AMPS in high purity (to 99.7%) and improved yield (up to 89%, based on isobutene) with the addition of liquid isobutene to an acrylonitrile / sulfuric acid / phosphoric acid mixture at 40°C.


2-Amino-1,2-dihydronaphthalene
2-Amino-1,2-dihydronapthalene (2-ADN), also known as 2-aminodilin (2-AD), is a stimulant drug. It is a rigid analogue of phenylisobutylamine and substitutes amphetamine for it in rat discrimination tests, although at approximately one fourth the potency. It is closely related to 2-aminotetralin (2-amino-1,2,3,4-tetrahydronaphthalene), which also substitutes for amphetamine, and is about two times as potent in comparison to it.


2-Amino-1-methyl-6-phenylimidazo(4,5-b)pyridine
PhIP (2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine) is one of the most abundant heterocyclic amines (HCAs) in cooked meat. PhIP is formed at high temperatures from the reaction between creatine or creatinine (found in muscle meats), amino acids, and sugar. PhIP formation increases with the temperature and duration of cooking and also depends on the method of cooking and the variety of meat being cooked. The U.S.  Department of Health and Human Services National Toxicology Program has declared PhIP as "reasonably anticipated to be a human carcinogen". International Agency for Research on Cancer (IARC), part of World Health Organization, has classified PhIP as IARC Group 2B carcinogen (i.e.,  possibly carcinogenic to humans). There is sufficient evidence in experimental animals, as well as in vitro models, for the carcinogenicity of PhIP.


2-Amino-1-methyl-6-phenylimidazo(4,5-b)pyridine, Sources of PhIP
PhIP has been found in cooked beef, pork, chicken, and fish products. Exposure to PhIP depends on the eating habits of the individual and can vary up to 5000-fold. Exposure is also related to the type of meat, doneness, cooking method, and quantity consumed. Individual exposures can differ due to various anti-carcinogens in the diet. Different cooking methods for meat (broiling, grilling, frying, roasting, pan drippings) all contribute to formation of PhIP.


2-Amino-1-methyl-6-phenylimidazo(4,5-b)pyridine, PhIP and cooking methods
Studies examining the amount of PhIP in cooked meats have shown that high levels of exposure are possible. Doneness levels of meat (rare, medium, well-done, and very well-done) are factors in the development of PhIP. Methods to reduce formation of PhIP in meats include decreasing the temperature at which the meat is cooked, decreasing the length of cooking time, pre-heating meat in the microwave oven (which reduces creatine), and marinating the meat.


2-Amino-1-methyl-6-phenylimidazo(4,5-b)pyridine, Dietary intake of PhIP
Determining dietary intake of PhIP can be obtained by more or one ways. One method used is a Food Frequency Questionaries (FFQ) which surveys a population on their estimated consumption of cooked meats. Another method directly measures the quantity of PhIP in a cooked meat sample. However, because the formation of PhIP in cooked meat items is dependent on temperature, cooking time, and cooking method, variations do occur in the direct measurement method. Direct measurement methods have determined dietary intake levels of PhIP to range from 0.07-4.3 ng/kg per day.


2-Amino-1-methyl-6-phenylimidazo(4,5-b)pyridine, Metabolism
Metabolic activation is required for PhIP to function as a mutagen. Therefore, the cancer risk posed by PhIP depends on the extent at which PhIP is metabolized. After absorption, PhIP is converted to a genotoxic metabolite in the liver by Phase I enzyme N-oxidation by Cytochrome P-450 1A2 (CYP1A2). PhIP can be further metabolized into a more potent metabolite through O-acetylation by hepatic or colonic N-acetyltransferase 1 (NAT1) and N-acetyltransferase 2 (NAT2), or by sulfotransfereases. However, PhIP may also undergo a detoxification pathway through Phase II conjugation reaction via UDP-glucuronosyltransferases (UGTs) to form N-glucuronide conjugates.


2-Amino-1-methyl-6-phenylimidazo(4,5-b)pyridine, Metabolism
PhIP's nitrenium ion intermediate is a powerful electrophile that has propensity to form C-8 guanine adducts with the DNA. In addition, some of these metabolic enzymes are inducible and have polymorphic variation. CYP1A2 displays a 40-fold variation in expression among humans and can be induced by smoking, diet, and chronic hepatitis. The expression of UGTs also displays inducibility; however, NATs do not. Individuals can be classified as either rapid or slow N-oxidizers and O-acetylators by assessing CYP1A2 and NAT2 activities. Individuals with the rapid phenotype of either CYP1A2 or NAT2 metabolize PhIP more effectively and are therefore at greater risk of PhIP's carcinogenic metabolite and could be at a higher risk of cancer.


2-Amino-1-methyl-6-phenylimidazo(4,5-b)pyridine, Animal studies and PhIP
Rats were fed PhIP at concentrations of 25, 100, and 200 ppm. The rats gained weight throughout the experiment, but feeding concentration of PhIP remained constant. Rats were fed PhIP ad libitum at concentrations of 12.5 and 50ppm. Rats developed mammary tumors at each concentration of PhIP administered. An in vivo study found mice injected with 5, 10, 12, 18, 20, 24, 28, 32, or 36 mg/kg bw showed a strong correlation between consumption of PhIP and genetic damage.


2-Amino-1-methyl-6-phenylimidazo(4,5-b)pyridine, Risk assessments for PhIP
There is no dose [of PhIP] without effect. Therefore, a margin of exposure (MOE) based on the benchmark lower confidence limit (BMDL) reference has been developed for PhIP in relation to prostate and mammary carcinomas.


2-Amino-1-methyl-6-phenylimidazo(4,5-b)pyridine, Associated cancers
Numerous in vivo and in vitro studies have demonstrated that PhIP is a potent mutagen and can induce tumors of multiple sites in animal models. PhIP was positive in bacterial (Ames) test and induced chromosomal abnormalities in human and Chinese hamster cells in vitro. PhIP has also formed DNA adducts in vivo in both rats and monkeys. PhIP has been tested for carcinogenicity in both mice and rats by oral administration. Increases in lymphomas were seen in mice and increases in adenocarcinomas of the small and large intestine in males and mammary adenocarcinomas in female were seen in rats.


2-Amino-1-methyl-6-phenylimidazo(4,5-b)pyridine, Associated cancers
Also, an increasing number of epidemiological studies have evaluated the association of well-done meat intake and HCA exposure with cancer risk in humans. In general, these studies have reported that high intake of well-done and/or high exposure to PhIP may be associated with cancer of the colorectum, breast, prostate, pancreas, lung, stomach, and esophagus.


2-Amino-1-methyl-6-phenylimidazo(4,5-b)pyridine, Associated cancers
PhIP has been shown to induce DNA adducts and mutations. These adducts have been found in a wide variety of sensitive tissues and organs such as the colon. However, adducts also formed in sites that did not commonly form tumors, such as the kidneys. In humans receiving a dose of PhIP equivalent to that found in very well-done chicken, DNA and protein adducts were formed in the colon and blood. However, the adducts were unstable and declined over a 24-hour period.


2-Amino-3-carboxymuconic semialdehyde
2-Amino-3-carboxymuconic semialdehyde is an intermediate in the metabolism of tryptophan in the tryptophan-niacin catabolic pathway. Quinolinate is a neurotoxin formed nonenzymatically from 2-amino-3-carboxymuconic semialdehyde in mammalian tissues. 2-Amino-3-carboxymuconic semialdehyde is enzymatically converted to 2-aminomuconate via 2-aminomuconic semialdehyde.


2-Amino-4-deoxychorismate dehydrogenase
2-Amino-4-deoxychorismate dehydrogenase (EC , ADIC dehydrogenase, 2-amino-2-deoxyisochorismate dehydrogenase, SgcG) is an enzyme with systematic name (2S)-2-amino-4-deoxychorismate:FMN oxidoreductase. This enzyme catalyses the following chemical reaction


2-Amino-4-deoxychorismate dehydrogenase
This enzyme participates in the formation of the benzoxazolinate moiety of the enediyne antitumour antibiotic C-1027].


2-Amino-4-deoxychorismate synthase
2-amino-4-deoxychorismate synthase (EC , ADIC synthase, 2-amino-2-deoxyisochorismate synthase, SgcD) is an enzyme with systematic name (2S)-2-amino-4-deoxychorismate:2-oxoglutarate aminotransferase. This enzyme catalyses the following chemical reaction


2-Amino-4-deoxychorismate synthase
This enzyme requires Mg2+. The reaction occurs in the reverse direction.


2-Amino-4-hydroxy-6-pyrophosphoryl-methylpteridine
2-Amino-4-hydroxy-6-pyrophosphoryl-methylpteridine (7,8-Dihydropterin pyrophosphate, dihydropterin-CH2OH-diphosphate) is a pteridine; a precursor to dihydrofolic acid.


2-Amino-5-formylamino-6-(5-phospho-D-ribosylamino)pyrimidin-4(3H)-one
2-Amino-5-formylamino-6-(5-phospho-D-ribosylamino)pyrimidin-4(3H)-one is a metabolite in the riboflavin biosynthesis pathway. It is formed from GTP by the enzyme GTP cyclohydrolase IIa which catalyzes the hydrolysis of the 8,9 bond in the guanine group and loss of the beta and gamma phosphate groups. The molecule is deformylated by 2-amino-5-formylamino-6-ribosylaminopyrimidin-4(3H)-one 5'-monophosphate deformylase as the second step in the archaeal riboflavin biosynthetic pathway.


2-Aminoacetanilide
2-Aminoacetanilide is a chemical compound which is a amino derivative of acetanilide and ortho-isomer of aminoacetanilide. There are two other isomers of aminoacetanilide, 3-aminoacetanilide and 4-aminoacetanilide. Aminoacetanilide derivatives are important synthetic intermediates in heterocyclic and aromatic synthesis. These derivatives have found applications in pharmaceutical industry and dyes and pigment industry.


2-Aminoacetanilide, Uses
2′-Aminoacetanilide is starting material for the synthesis of 2-Methylbenzimidazole, N-(2-(1,3-Dimethyl-2,4-dioxo-5-phenyl-3,4-dihydro-1H-pyrrolo[3,4-d]pyrimidin-6(2H)-yl)phenyl)-5-methylfuran-2-carboxamide, and Azobenzothiazole dyes, N-[2-(6-nitrobenzothiazol-2-ylazo)phenyl]acetamide and N-[2-(benzothiazol-2-ylazo)phenyl]acetamide. Benzimidazoles have been synthesized by cyclization of 2′-Aminoacetanilide by CO2 in the presence of H2 using RuCl2(dppe)2 as the catalyst.


2-Aminobenzaldehyde
2-Aminobenzaldehyde is an organic compound with the formula C6H4(NH2)CHO. It is one of three isomers of aminobenzaldehyde. It is a low-melting yellow solid that is soluble in water.


2-Aminobenzaldehyde, Preparation and reactions
It is usually prepared by reduction of 2-nitrobenzaldehyde with iron or iron(II) sulfate. Like related aminoaldehydes, it is unstable with respect to self-condensation.


2-Aminobenzaldehyde, Preparation and reactions
2-Aminobenzaldehyde is used to prepare quinolines by the Friedländer synthesis:


2-Aminobenzaldehyde, Preparation and reactions
By template reactions, it also forms trimeric and tetrameric condensation products that have been studied as ligands.


2-Aminobiphenyl
2-Aminobiphenyl (2-APB) is an organic compound with the formula C6H5C6H4NH2. It is an amine derivative of biphenyl. It is a colorless solid, although aged samples can appear colored even black. Palladacycles obtained from 2-aminobiphenyl are popular catalysts for cross-coupling.


2-Aminoethoxydiphenyl borate
2-Aminoethoxydiphenyl borate (2-APB) is a chemical that acts to inhibit both IP3 receptors and TRP channels (although it activates TRPV1, TRPV2, & TRPV3 at higher concentrations). In research it is used to manipulate intracellular release of calcium ions (Ca2+) and modify TRP channel activity, although the lack of specific effects make it less than ideal under some circumstances. Additionally, there is evidence that 2-APB acts directly to inhibit gap junctions made of connexin. Increasing evidence showed that 2-APB is a powerful modifier of store-operated calcium channels (SOC) function, low concentration of 2-APB can enhance SOC while high concentration induces a transient increase followed by complete inhibition.


2-Aminoindane
2-Aminoindane (2-AI) is a research chemical with applications in neurologic disorders and psychotherapy that has also been sold as a designer drug. It acts as a selective substrate for NET and DAT.


2-Aminoindane, Therapeutic and illicit uses
Synthetic aminoindanes were originally developed in the context of anti-Parkinsonian drugs as a metabolite of rasagiline and as a tool to be used in psychotherapy. Deaths related to their toxic effects have been observed both in the laboratory in animal studies and in clinical encounters. 2-AI is a rigid analogue of amphetamine and partially substitutes for it in rat discrimination tests.


2-Aminoindane, Legal status
Sweden's public health agency suggested classifying 2-AI as a hazardous substance, on June 24, 2019.


2-Aminoindane, Chemical derivatives
There are a number of derivatives of 2-aminoindane and its positional isomer 1-aminoindane exist, including:


2-Aminoindane, Legality, China
As of October 2015 2-AI is a controlled substance in China.


2-Aminoindane, Legality, United States
2-Aminoindane is not scheduled at the federal level in the United States, but may be considered an analog of amphetamine, in which case purchase, sale, or possession could be prosecuted under the Federal Analog Act.


2-Aminoisobutyric acid
2-Aminoisobutyric acid (also known as α-aminoisobutyric acid, AIB, α-methylalanine, or 2-methylalanine) is the non-proteinogenic amino acid with the structural formula H2N-C(CH3)2-COOH. It is rare in nature, having been only found in meteorites, and some antibiotics of fungal origin, such as alamethicin and some lantibiotics.


2-Aminoisobutyric acid, Synthesis
In the laboratory, 2-aminoisobutyric acid may be prepared from acetone cyanohydrin, by reaction with ammonia followed by hydrolysis. Industrial scale synthesis can be achieved by the selective hydroamination of methacrylic acid.


2-Aminoisobutyric acid, Biological activity
2-Aminoisobutyric acid is not one of the proteinogenic amino acids and is rather rare in nature (cf. non-proteinogenic amino acids). It is a strong helix inducer in peptides due to Thorpe–Ingold effect of its gem-dimethyl group. Oligomers of AIB form 310 helices.


2-Aminoisobutyric acid, Ribosomal incorporation into peptides
2-Aminoisobutyric acid is compatible with ribosomal elongation of peptide synthesis. Katoh et al. used flexizymes and an engineered a tRNA body to enhance the affinity of aminoacylated AIB-tRNA species to elongation factor P. The result was an increased incorporation of AIB into peptides in a cell free translation system. Iqbal et al.. used an alternative approach of creating an editing deficient valine—tRNA ligase to synthesize aminoacylated AIB-tRNAVal. The aminoacylated tRNA was subsequently used in a cell-free translation system to yield AIB-containing peptides.


2-Aminomuconic acid
2-Aminomuconic acid is an intermediate in the metabolism of tryptophan.


2-Aminophenol
2-Aminophenol is an organic compound with the formula C6H7NO. Along with its isomer 4-aminophenol, it is an amphoteric molecule and a reducing agent. It is a useful reagent for the synthesis of dyes and heterocyclic compounds. Reflecting its slight hydrophilic character, white powder is moderately soluble in alcohols and can be recrystallized  from hot water.


2-Aminophenol, Synthesis and structure
2-Aminophenol (and its isomer, 4-aminophenol) is industrially synthesized by reducing the corresponding nitrophenol by hydrogen in the presence of various catalysts. The nitrophenols can also be reduced with iron.


2-Aminophenol, Synthesis and structure
The compound exhibits intra- and intermolecular hydrogen bonding involving the neighbouring amine and hydroxyl groups. As a result, 2-aminophenol has a relatively high melting point (174 °C) compared to other compounds with a similar molecular mass; for example, 2-methylphenol melts at 31 °C.


2-Aminophenol, Applications
2-Aminophenol has a variety of uses. As a reducing agent, it is marketed under the names of Atomal and Ortol to develop black-and-white photographs. 2-Aminophenol is an intermediate in the synthesis of dyes. It is particularly useful in yielding metal-complex dyes when diazotized and coupled to a phenol, naphthol, or other aromatic or resonant dye species. Metal complex dyes using copper or chromium are commonly used for producing dull colors. Tridentate ligand dyes are useful because they are more stable than their bi- or mono-dentate counterparts.


2-Aminophenol, Applications
Due to the adjacency of the amino and hydroxyl groups, 2-aminophenol readily forms heterocycles. These heterocycles, such as benzoxazoles, can be biologically active and useful in the pharmaceutical industry:


2-Aminopurine
2-Aminopurine, a purine analog of guanine and adenine, is a fluorescent molecular marker used in nucleic acid research. It most commonly pairs with thymine as an adenine-analogue, but can also pair with cytosine as a guanine-analogue;. For this reason it is sometimes used in the laboratory for mutagenesis.


2-Aminopyridine
2-Aminopyridine is an organic compound with the formula H2NC5H4N. It is one of three isomeric aminopyridines. It is a colourless solid that is used in the production of the drugs piroxicam, sulfapyridine, tenoxicam, and tripelennamine. It is produced by the reaction of sodium amide with pyridine, the Chichibabin reaction.


2-Aminopyridine, Structure
Although 2-hydroxypyridine converts significantly to the pyridone tautomer, the related imine tautomer (HNC5H4NH) is less important for 2-aminopyridine.


2-Aminopyridine, Toxicity
The acute toxicity is indicated by the LD50 = 200 mg/kg (rat, oral).


2-Aminotetralin
2-Aminotetralin (2-AT), also known as 1,2,3,4-tetrahydronaphthalen-2-amine (THN), is a stimulant drug with a chemical structure consisting of a tetralin group combined with an amine.


2-Aminotetralin
2-AT is a rigid analogue of phenylisobutylamine and fully substitutes for d-amphetamine in rat discrimination tests, although at one eighth the potency. It has been shown to inhibit the reuptake of serotonin and norepinephrine, and likely induces their release as well. It is also likely to act on dopamine on account of its full substitution of d-amphetamine in rodent studies.


2-Aminothiazoline-4-carboxylic acid
2-Aminothiazoline-4-carboxylic acid (ACTA) is the organosulfur compound and a heterocycle with the formula HO2CCHCH2SCNH2N. This derivative of thiazoline is an intermediate in the industrial synthesis of L-cysteine, an amino acid. ACTA exists in equilibrium with its tautomer 2-iminothiazolidine-4-carboxylic acid.


2-Aminothiazoline-4-carboxylic acid
It is produced by the reaction of methyl chloroacrylate with thiourea. It is also a biomarker for cyanide poisoning, as it results from the condensation of cysteine and cyanide.


2-Aminothiophenol
2-Aminothiophenol is an organosulfur compound with the formula C6H4(SH)(NH2). It is a colorless oily solid, although impure samples can be deeply colored. It is soluble in organic solvents and in basic water. It is a precursor to benzothiazoles, some of which are bioactive or are dyes. Isomers of aminothiophenols include 3-aminothiophenol and 4-aminothiophenol.


2-Aminothiophenol
2-Aminothiophenol can prepared in two steps, starting with the reaction of aniline with carbon disulfide followed by hydrolysis of the resulting mercaptobenzothiazole. It can also obtained by zinc reduction of 2-nitrobenzenesulfonyl chloride.


2-Arachidonoylglycerol
2-Arachidonoylglycerol (2-AG) is an endocannabinoid, an endogenous agonist of the CB1 receptor and the primary endogenous ligand for the CB2 receptor. It is an ester formed from the omega-6 fatty acid arachidonic acid and glycerol. It is present at relatively high levels in the central nervous system, with cannabinoid neuromodulatory effects. It has been found in maternal bovine and human milk. The chemical was first described in 1994-1995, although it had been discovered some time before that. The activities of phospholipase C (PLC) and diacylglycerol lipase (DAGL) mediate its formation. 2-AG is synthesized from arachidonic acid-containing diacylglycerol (DAG).


2-Arachidonoylglycerol, Occurrence
2-AG, unlike anandamide (another endocannabinoid), is present at relatively high levels in the central nervous system; it is the most abundant molecular species of monoacylglycerol found in mouse and rat brain (~5-10 nmol/g tissue). Detection of 2-AG in brain tissue is complicated by the relative ease of its isomerization to 1-AG during standard lipid extraction conditions. It has been found in maternal bovine as well as human milk.


2-Arachidonoylglycerol, Discovery
2-AG was discovered by Raphael Mechoulam and his student Shimon Ben-Shabat. 2-AG was a known chemical compound but its occurrence in mammals and its affinity for the cannabinoid receptors were first described in 1994-1995. A research group at Teikyo University reported the affinity of 2-AG for the cannabinoid receptors in 1994-1995, but the isolation of 2-AG in the canine gut was first reported in 1995 by the research group of Raphael Mechoulam at the Hebrew University of Jerusalem, which additionally characterized its pharmacological properties in vivo. 2-Arachidonoylglycerol, next with Anandamide, was the second endocannabinoid discovered. The cannabinoid established the existence of a cannabinoid neuromodulatory system in the nervous system.


2-Arachidonoylglycerol, Pharmacology
Unlike anandamide, formation of 2-AG is calcium-dependent and is mediated by the activities of phospholipase C (PLC) and diacylglycerol lipase (DAGL). 2-AG acts as a full agonist at the CB1 receptor. At a concentration of 0.3nM, 2-AG induces a rapid, transient increase in intracellular free calcium in NG108-15 neuroblastoma X glioma cells through a CB1 receptor-dependent mechanism. 2-AG is hydrolyzed in vitro by monoacylglycerol lipase (MAGL), fatty acid amide hydrolase (FAAH), and the uncharacterized serine hydrolase enzymes ABHD2, ABHD6 and ABHD12.


2-Arachidonoylglycerol, Pharmacology
The exact contribution of each of these enzymes to the termination of 2-AG signaling in vivo is unknown, though it is estimated that MAGL is responsible for ~85% of this activity in the brain. There have been identified transport proteins for 2-arachidonoylglycerol and anandamide. These include the heat shock proteins (Hsp70s) and fatty acid binding proteins (FABPs).


2-Arachidonoylglycerol, Biosynthesis
2-Arachidonoylglycerol is synthesized from arachidonic acid-containing diacylglycerol (DAG), which is derived from the increase of inositol phospholipid metabolism by the action of diacylglycerol lipase. The molecule can also be formed from pathways like the hydrolysis derived (by diglyceride) from both phosphatidylcholine (PC) and phosphatidic acid (PAs) by the action of DAG lipase and the hydrolysis of arachidonic acid-containing lysophosphatidic acid by the action of a phosphatase.


2-Arachidonyl glyceryl ether
2-Arachidonyl glyceryl ether (2-AGE, Noladin ether) is a putative endocannabinoid discovered by Lumír Hanuš and colleagues at the Hebrew University of Jerusalem, Israel. It is an ether formed from the alcohol analog of arachidonic acid and glycerol. Its isolation from porcine brain and its structural elucidation and synthesis were described in 2001.


2-Arachidonyl glyceryl ether, Discovery
Lumír Hanuš, Saleh Abu-Lafi, Ester Fride, Aviva Breuer, Zvi Vogel, Deborah E. Shalev, Irina Kustanovich, and Raphael Mechoulam found the endogenous agonist of the cannabinoid receptor type 1 (CB1) in 2000. The discovery was 100 gram of porcine brain, (approximately a single brain) was added to a mixture of 200 mL of chloroform and 200 mL of methanol and mixed in a laboratory blender for 2 minutes. 100 mL of Water was then added, and the mixing process continued for another minute. After this, the mixture was filtered. Two layers then formed and the layer of water-methanol was separated and evaporated when pressure was reduced. Synaptosomal membranes were prepared from 250g of the brains of Sabra male rats. A Hewlett Packard G 1800B GCD system that has a HP-5971 GC with electron ionization detector was used.


2-Arachidonyl glyceryl ether, Production
The production of the endocannabinoid is enhanced in normal, but not in endothelium-denuded rat aorta on reacting with carbachol, a parasympathomimetic drug. It potently reduces blood pressure in rats and may represent an endothelium-derived hypotension factor.


2-Arachidonyl glyceryl ether, Production
2-Arachidonyl glyceryl ether's structure can be determined by mass spectrometry and Rutherford backscattering spectrometry. It was confirmed by comparison with a synthetic sample of the endocannabinoid. It binds to the Cannabinoid receptor type 1 (Ki = 21.2 ± 0.5 nM), which causes sedation, hypothermia, intestinal immobility, and mild antinociception in mice. The endocannabinoid exhibits Ki values of 21.2 nM and >3 μM at the Cannabinoid receptor type 1 and the peripheral cannabinoid receptors.


2-Arachidonyl glyceryl ether, Production
The presence of 2-AGE in body tissue is disputed. Although a research group from Teikyo University, Kanagawa, Japan could not detect it in the brains of mice, hamsters, guinea-pigs or pigs, two other research groups successfully detected it in animal tissues.


2-Arachidonyl glyceryl ether, Pharmacology
2-AGE binds with a Ki of 21 nM to the CB1 receptor and 480 nM to the CB2 receptor. It shows agonistic behaviour on both receptors and is a partial agonist for the TRPV1 channel. After binding to CB2 receptors it inhibits adenylate cyclase and stimulates ERK-MAPK and regulates calcium transients. In comparison to 2-arachidonoyl glycerol, noladin is metabolically more stable resulting in a longer half-life. It lowers Intraocular pressure, increases the uptake of GABA in the globus pallidus of rats and is neuroprotective by binding to and activation of PPARα.


2-Bekat (Tashkent Metro)
2-Bekat is a station of the Tashkent Metro on Chilonzor Line. It was put into operation on December 26, 2020, as part of the third section of the Chilanzar line, between Olmazar and 5-Bekat. The station is located between 1-Bekat and 3-Bekat.


2-Bekat (Tashkent Metro)
The planned name for the station was Toshkent halqa yo‘li (Tashkent Circle Road), however, the station was opened as 2-Bekat, which simply means Station-2.


2-Benzylpiperidine
2-Benzylpiperidine is a stimulant drug of the piperidine class. It is similar in structure to other drugs such as methylphenidate and desoxypipradrol but around one twentieth as potent, and while it boosts norepinephrine levels to around the same extent as d-amphetamine, it has very little effect on dopamine levels, with its binding affinity for the dopamine transporter around 175 times lower than for the noradrenaline transporter. 2-benzylpiperidine is little used as a stimulant, with its main use being as a synthetic intermediate in the manufacture of other drugs.


2-Bromo-1-chloropropane
2-Bromo-1-chloropropane, C3H6BrCl, is an alkyl halide. This simple compound has a chiral center and is used sometimes to determine the enantiomeric resolution of simple chromatographic methods.


2-Bromo-4,5-methylenedioxyamphetamine
2-Bromo-4,5-methylenedioxyamphetamine (6-Bromo-MDA) is a lesser-known psychedelic drug and a substituted amphetamine. It was first synthesized by Alexander Shulgin. In his book PiHKAL, the dose is listed as 350 mg and the duration unknown. It produces stimulant effects but with no psychedelic or empathogenic action. Very little data exists about its pharmacological properties, metabolism, and toxicity.


2-Bromo-LSD
2-Bromo-LSD, also known as BOL-148, is a derivative of lysergic acid invented by Albert Hofmann, as part of the original research from which the closely related compound LSD was also derived. 2-Bromo-LSD was found to be inactive as a psychedelic and so was comparatively little researched for many years, although its similar behavior in the body made it useful for radiolabelling studies. It was found to bind to many of the same receptors as LSD, but acting as a neutral antagonist rather than an agonist.


2-Bromo-LSD
However its generally similar behavior to LSD in some respects has shown to be very useful in one specific area, the treatment of cluster headaches. These debilitating attacks have been known for some time to be amenable to treatment with certain hallucinogenic drugs such as LSD and psilocybin, but because of the illegal status of these drugs and the kind of mental changes they induce, research into their medical use has been slow and therapeutic application limited to very specific circumstances under strict supervision.


2-Bromo-LSD
It had been thought that this specific therapeutic action against cluster headaches was limited to hallucinogenic drugs of this type, and would always present a major barrier to their clinical use. However a serendipitous discovery found that 2-bromo-LSD is also able to produce this therapeutic effect, despite lacking the other effects of LSD. This has led to a resurgence of interest and research into 2-bromo-LSD and its possible medical uses. Some isolated incidents of hallucinogenic responses have been reported, but as with other non-hallucinogenic LSD analogues such as lisuride, this appears to be a rare side effect occurring only in individuals with an as yet unexplained susceptibility to this reaction. 2-Bromo-LSD reportedly attenuates the effects of LSD in humans.


2-Bromoanisole
2-Bromoanisole is an organobromide with the formula BrC6H4OCH3. A colorless liquid, it is one of three isomers of bromoanisole, the others being 3-bromoanisole and 4-bromoanisole. It is a standard coupling partner in metal catalyzed coupling reactions. These reactions include Heck reactions, Buchwald-Hartwig coupling, Suzuki couplings, and Ullmann condensations. The corresponding Grignard reagent readily forms. It is a precursor to o-anisaldehyde.


2-Bromobutane
2-Bromobutane is an isomer of 1-bromobutane. Both compounds share the molecular formula C4H9Br. 2-Bromobutane is also known as sec-butyl bromide or methylethylbromomethane. Because it contains bromine, a halogen, it is part of a larger class of compounds known as alkyl halides. It is a colorless liquid with a pleasant odor. Because the carbon atom connected to the bromine is connected to two other carbons the molecule is referred to as a secondary alkyl halide.


2-Bromobutane
2-Bromobutane is relatively stable, but is toxic and flammable. When treated with a strong base, it is prone to undergo an E2 reaction, which is a bimolecular elimination reaction, resulting in (predominantly) 2-butene, an alkene (double bond). 2-Bromobutane is an irritant, and harmful if ingested. It can irritate and burn skin and eyes.


2-Bromobutyric acid
2-Bromobutyric acid is a carboxylic acid with the molecular formula C4H7BrO2. It is a colorless liquid. The 2-position is stereogenic, so there are two enantiomers of this compound. 2 -Bromobutyric acid is mainly used as a building block chemical, such as in the preparation of Levetiracetam, an anticonvulsant medication.


2-Bromobutyric acid, Production
(±)-2-Bromobuyric acid may be prepared by the acid-catalyzed Hell–Volhard–Zelinsky reaction, where butyric acid is treated with elemental bromine.


2-Bromoethyl ether
2-Bromoethyl ether (or Bis(2-bromoethyl) ether) is an organobromine compound that is also an ether. It is used in the manufacture of pharmaceuticals and crown ethers.


2-Bromohexane
2-Bromohexane is the organobromine compound with the formula CH3CH(Br)(CH2)3CH3. It is a colorless liquid. The compound is chiral. Most 2-bromoalkanes are prepared by addition of hydrogen bromide to the 1-alkene. Markovnikov addition proceeds in the absence of free-radicals, i.e. give the 2-bromo derivatives.


2-Bromomescaline
2-Bromomescaline (2-Br-M) is a derivative of the phenethylamine hallucinogen mescaline which has an unusual 2-bromo substitution. It is an agonist for serotonin receptors, with a binding affinity of 215 nM at 5-HT1A, 513 nM at 5-HT2A and 379 nM at 5-HT2C, so while it is around ten times more tightly binding than mescaline at 5-HT1A and 5-HT2A receptors, it is over twenty times more potent at 5-HT2C.


2-Bromopropane
2-Bromopropane, also known as isopropyl bromide and 2-propyl bromide, is the halogenated hydrocarbon with the formula CH3CHBrCH3. It is a colorless liquid. It is used for introducing the isopropyl functional group in organic synthesis. 2-Bromopropane is prepared by heating isopropanol with hydrobromic acid.


2-Bromopropane, Preparation
2-Bromopropane is commercially available. It may be prepared in the ordinary manner of alkyl bromides, by reacting isopropanol with phosphorus and bromine, or with phosphorus tribromide.


2-Bromopropane, Safety
The bromine atom is at the secondary position, which allows the molecule to undergo dehydrohalogenation easily to give propene, which escapes as a gas and can rupture closed reaction vessels. When this reagent is used in base catalyzed reactions, potassium carbonate should be used in place of sodium or potassium hydroxide.


2-Bromopyridine
2-Bromopyridine is an organic compound with the formula BrC5H4N. It is a colorless liquid that is used as an intermediate in organic synthesis. It can be prepared from 2-aminopyridine via diazotization followed by bromination.


2-Bromopyridine, Reactions
2-Bromopyridine reacts with butyllithium to give 2-lithiopyridine, which is a versatile reagent. Pyrithione can be prepared in a two-step synthesis from 2-bromopyridine by oxidation to the N-oxide with a suitable peracid followed by substitution using either sodium dithionite or sodium sulfide with sodium hydroxide to introduce the thiol functional group.


2-Bromothiophene
2-Bromothiophene is an organosulfur compound with the formula C4H3BrS. It is a colorless liquid. Unlike 3-bromothiophene, the 2-bromo isomer is prepared directly by partial bromination of thiophene. It is a precursor to several drugs, including tipepidine, ticlopidine, and clopidogrel.


2-Bromothiophene, Safety
The LD50 is low, 200 – 250 mg/kg (oral, rat).