London Underground 1960 Stock - Driving Motor Cars

Driving Motor Cars

The twelve aluminium-bodied motor cars were ordered from Cravens in 1958, and each was equipped with four traction motors, instead of the two which previous stock had used. They were controlled by a Pneumatic Camshaft Motor (PCM) controller, where an air-operated camshaft controlled the switching of the motors, which was itself governed by an accelerating relay. This system had proved reliable in the control of two motors. In order for it to control four, without a major re-design, pairs of motors were wired together in series, and the controller switched between all four motors operating in series, and the two pairs operating in parallel. In order to protect against wheel-spin, the contoller automatically reset if one motor of a pair began to run faster than the other. Whereas previous bogies had been asymmetric, to ensure that more weight was carried by the axle driven by the motor, the pivot was central as every axle carried a motor. One further innovation was that the fully automatic couplers at the outer ends of the trains were not "handed". Previously, trains were designated with 'A' and 'D' ends, and could only be coupled together by joining an 'A' end of one train to a 'D' end of another. This could cause operational problems, particularly on a line such as the Central, where operating a train right round the Hainualt loop resulted in it facing the wrong way. The 1960 stock avoided this problem by duplicating most of the connections in the automatic coupler, so that trains could be joined either way round. The cars also included a flat floor for the first time, rather than having a raised section over the motor bogies.

The first of the new trains entered service on 9 November 1960. The driving motor cars were numbered 3900-3911 although the first two cars were delivered by Cravens numbered 3000 and 3001 but were renumbered 3900 and 3901 before entering service. To make the sets up to four cars, each incorporated two trailer cars which were rebuilt from old Pre-1938 Standard Stock. Two units were intended to be coupled together, forming an eight-car train. The 1960 Stock initially ran on the main Central Line, before being cascaded to the Hainault Loop. One of the main factors affecting the use of 1962 stock for the Central Line upgrade, rather than a production run of 1960 stock, was the cost of refurbishing the Standard Stock cars to run with the new driving motor cars.