The New Zealand Railways Magazine, Volume 10, Issue 11 (February 1, 1936)
Passenger traffic in the Bristol district is particularly heavy, especially in the summer months. In addition to the local business, and the express services with London and South Wales, an enormous traffic passes through Bristol during the holiday season in connection with passenger movement between the industrial north and midlands and the Devon and Cornwall vacation resorts. Recently, light rail motor-cars have been introduced with success in the Bristol area, and a new streamlined, oil-engined railcar takes the form of a twinengined unit designed for hauling a trailer. The railcar and trailer seat 148 passengers, and speeds of up to 65 m.p.h. are attained.
Both engines of the new unit are mounted outside the frames, one engine driving on to the two axles of one bogie, and the other driving the opposite bogie in the same manner. Viewed in plan, the engine on the left drives the rear bogie, and that on the right the forward bogie. The two engines and their accessory equipment are carried on a sub-frame slung below the main frame. Each engine transmits its drive through a fluid flywheel and a Wilson preselective gearbox, provision being made for five speeds. For the final drive, taken to the outside of the bogie axles through propellor shafts provided with needle roller bearing universal joints, spiral bevel gearing is employed. By an ingenious arrangement of the gearing, reversal in the direction of travel is provided for. The new car is 62 ft. long overall, and 8 ft. wide.