The Southern Railway also built two mixed-traffic electric locomotives, numbered CC1 and CC2 under Bulleid's numbering system. They were designed by Bulleid and Alfred Raworth, and were renumbered 20001 and 20002 after nationalisation. At this time a third locomotive was under construction, and was numbered 20003 in 1948. The locomotives were later classified as British Rail Class 70. These incorporated a cab design similar to that of the 2HAL (2-car "Ha"lf "L"avatory electric stock) design constructed from 1938. This was due to ease of construction by welding, which allowed both cheap and speedy construction. With the outbreak of war in 1939, most new locomotive construction projects were put on hold in favour of the war effort, although construction of CC1 and CC2 was exempted from this because of promised savings in labour and fuel over steam locomotives.