While they were similar in many respects to the 1938 stock, the main differences were that the body panels were unpainted aluminium, rather than painted steel, a rubber suspension system was used on the bogies, reducing the number of parts that required regular maintenance, and the lighting was provided by fluorescent tubes, rather than incandescent bulbs. The front ends were flatter above the roof line, as the destination blind was fitted over the front cab door, rather than below the cab window. Control was provided by a PCM (Pneumatic Cam Motor) controller, supplied by Associated Electrical Industries, which had proved to be reliable in the 1938 stock. As with the 1938 stock, the DM cars seated 42 (but were not equipped with tip-up seats), the NDM and T cars seated 40 each.