M25 motorway the east of Gravesend and Grays, the Lower Thames Crossing, in order to relieve congestion on the A282 Dartford Crossing and connect the M25 at North Ockendon in Essex with the M2 in Kent. At Junction 5, the clockwise carriageway of the M25 is routed off the main north–south dual carriageway onto the main east–west dual carriageway with the main north–south carriageway becoming the A21. In the opposite direction, to the east of the point where the M25 diverges from the main east–west carriageway, that carriageway become the M26 motorway. The radial distance from London (taken as Charing Cross) varies
London Underground infrastructure in 1999, and key interchange stations such as King's Cross St. Pancras, Victoria station and Green Park becoming step-free. Over 28 stations will become step-free over the next 10 years, taking the total step-free stations to over 100. In October 2015, TfL installed the first incline lift on the UK transport network, at Greenford station. The London Underground comprises eleven lines. London Underground trains come in two sizes, larger sub-surface trains and smaller deep-tube trains. Since the early 1960s, all passenger trains have been electric multiple units with sliding doors and a train last ran with a guard in 2000.