The C&SLR was opened just a few years after the very first use of electricity to drive rail vehicles (trains or trams) and the primitive locomotives reflected this.

From 1903, the MR and the DR began to electrify the central parts of their lines for use by electric multiple units (EMUs).

On both railways carriages were hauled by electric locomotives that were exchanged for a steam engine to run over un-electrified distant sections.

When the City and South London Railway (C&SLR) was authorised in 1884, it was intended to be a cable-hauled line, but during the construction phase, the promoters decided to use electric traction, despite the fact that the technology was in its infancy.

[1] Two prototype locomotives were built by Mather & Platt in 1889, to a design by Dr Edward Hopkinson, with Beyer, Peacock and Company supplying many of the mechanical parts.

There was a single driving position at one end of the locomotive with the power controller on one side and the Westinghouse air-brake valve and hand-brake column on the other.

15 and 16 were built by Siemens with a modified design of motor,[4] which attempted to overcome the problem of burnt-out armatures that had plagued the line since its opening.

23 to 52 were built by Crompton to an improved design, including nose-suspended motors connected to the axles by a single reduction gear, but still bore a strong external resemblance to the original locomotives.

[5] Following the introduction of new locomotives and the abandonment of the restrictive King William Street terminus in 1900, the C&SLR was able to run trains with four cars.

[7] Six-carriage trains were briefly operated in 1914/15 and from October 1923[8] before the last part of the line was closed for reconstruction and tunnel enlargement in November 1923.

[9] The enlarged tunnels allowed the locomotive hauled trains to be replaced by 'Standard' Stock electric multiple units.

These long, low locomotives had deep plate frames, a central cab and equipment compartments on front and rear.

Complaints from local residents started immediately after the service commenced and were such that the Board of Trade imposed a speed limit until modifications could be made.

This was achieved by only using series mode on the controller, but by 1901, three of the locomotives had been rebuilt with new bogies and nose-suspended GE55 motors, reducing the unsprung weight to 11 tons.

[11] Six and seven car trains were run, and as on the City and South London Railway, locomotives were stepped back at the termini.

These became the first operational multiple units in Europe, and the benefits of virtually eliminating vibration and the ease of reversing them at the termini resulted in an order for 64 motor cars being placed.

[17] In 1905, the District Railway bought ten bogie boxcab locomotives that looked similar to their multiple units, but were only 25 feet (7.6 m) long.

[18] The locomotives were used to haul London and North Western Railway passenger trains on the electrified section of the Outer Circle route between Earl's Court and Mansion House.

In December 1908, these services terminated at Earl's Court[19] and the locomotives were used to haul District line trains, one coupled to each end of a rake of four trailer cars.

[20] From 1910, trains from the London, Tilbury and Southend Railway (LT&SR) were extended over the District line, the steam locomotives being exchanged for electric ones at Barking.

[21] Two rakes of carriages were provided by the London, Tilbury and Southend Railway, and were hauled over the District tracks by the locomotives working in pairs.

[18] For moving rolling stock around the main workshops at Acton, four electric locomotives were created out of withdrawn passenger vehicles.