who designed it?
Mather & Platt
City and South London Railway
The system operated using electric locomotives built by Mather & Platt collecting a voltage of 500 volts (actually +500 volts in the northbound tunnel and −500 volts in the southbound) from the third rail and pulling several carriages
what is the city and south london railway? The first deep-level underground "tube" railway in the world when was it built? UNANSWERABLE
wiki:20646422
City and South London Railway [SEP] Haulage and infrastructure
A depot and generating station were constructed at Stockwell. Owing to the limited capacity of the generators, the stations were originally illuminated by gas. The depot was on the surface, and trains requiring maintenance were initially hauled up via a ramp although, following a runaway accident, a lift was soon installed. In practice, most rolling stock and locomotives went to the surface only for major maintenance.