 A Stock was 4-car units that could operate as four- or eight-car trains; normally operated as eight cars, a 4-car unit operated the Chesham shuttle.One person operation of the trains was proposed in 1972, but due to conflict with the trades unions was not introduced on the line until 1986.Although the East London line had been an isolated shuttle since 1939, it was shown on London Underground maps as part of the Metropolitan line until 1968.