Not a Tunnel Motor, a Tube Motor.
London Underground battery-electric locomotive 22 is seen leading an engineering train into Hyde Park Corner station on the Piccadilly Line, en route to an overnight job site. Locomotive 20 would bring up the rear of the train. These two units were part of a batch of 13 built by Metro-Cammell between 1964 and 1965, and are used in work sites as they are capable of operating when the traction power is turned off. Battery operation is used due to the poor ventilation in the deep-level tube lines, which would not be able to clear out the exhaust from internal combustion engines.
