Electric locomotives were first used on the London Underground
when the first deep-level tube line, the City and South London Railway
(C&SLR), was opened in 1890. The first underground railways in London, the Metropolitan Railway
(MR) and the Metropolitan District Railway
(MDR), used specially built steam locomotives
to haul their trains through shallow tunnels which had many ventilation openings to allow steam and smoke to clear from the tunnels. It was impossible to use steam locomotives in the small unvented tubular tunnels of the deep-level lines, and the only options were rope haulage (as on the Glasgow Underground
) or electric locomotives.
The C&SLR was opened just a few year after the very first use of electricity to drive rail vehicles (trains or trams) and the primitive locomotives reflected this. Over the next 15 years, motors became smaller and (size for size) far more powerful; gear drives and motor suspension were developed and reliable multiple unit control became available. Electric multiple unit trains became the standard, but electric locomotives were still being built.
From 1903, the MR and the MDR began to electrify the central parts of their lines and purchased electric locomotives to haul normal coaches although more distant sections of the lines remained unelectrified and journeys required electric locomotives to be swapped with a steam engine. The last steam-hauled passenger trains were not replaced until 1961.
When not hauling passenger trains,... Read More