The British Rail Class 415 (or 4EPB) was a suburban 750 V DC third rail electric multiple unit commissioned by the Southern Region of British Railways. Built between 1951 and 1957, it became the most numerous class on the region after the withdrawal of the 4SUBs. The final trains were withdrawn in the 1990s, replaced by Class 455, 456, 465 and 466. The British Rail designation Class 415 was applied to a group of four coach, third rail electric multiple units constructed between 1951 and 1961 and in service from 1951 to 1995. Construction The 4EPB units (4-car Electro-Pneumatic Brake) were a development of the Southern Railway (SR) 4Sub design, but incorporating electro-pneumatic brakes, unit-to-unit buckeye couplings, roller blind headcode displays in place of the stencil holders used previously, and without external doors to the driver's cab – access was via the adjacent guard's compartment. There were motor-generators for the lighting and current control whereas previous practice had been to use series lighting and a voltage divider for the control circuits. The first units built were based on Southern Railway designs and utilised standard Southern railway jigs, being constructed using standard Southern Railway components such as doors and being built to a standard Southern body profile; they were mounted on underframes reclaimed from older cars, the wooden bodies of which were scrapped. The doyen of the class, unit 5001, was completed at Eastleigh in 1951. Further examples were built at Eastleigh up until 1957. Altogether, 213 units were built: in 78 of the units, one car was a former 4-SUB trailer rewired to operate with 4-EPB stock. The motor bogies of cars 14001–106 (units 5001–53) were known as the "eastern" type, and had a wheelbase of ; those of cars 14201–520 (units 5101–5260) were known as the "central" type, and had a wheelbase of . The "eastern" motor bogies were later replaced by the "central" type, the process being completed in 1964, but the cars (and units) were not renumbered. The formation of each unit was similar to the later 4-SUB units. That is, there were two driving motor brake third open cars comprising a driving cab, guard's compartment and eight-bay passenger saloon having 82 seats; between these were a trailer third having ten compartments providing 120 seats (cars 15005 and 15038 had nine compartments seating 108) and a trailer third open having ten seating bays providing 102 seats. The