|Engine:||2 Siemens traction motors (530-600v DC third rail)|
|Power:||120 hp (90 kW)|
75S had a driving cab at only one end and had two nose-suspended traction motors of the same type used on the passenger stock  with air brakes fed from a reservoir. It remained in service until 1969 and has been preserved by the National Railway Museum. A second electric locomotive (74S later DS74), a larger Bo-Bo type with a central steeple-cab was also built for the line though was moved to work on the surface at Wimbledon in 1915 .
|75S as preserved at NRM Shildon in Southern Railways livery|
|Another view of 75S|
 John C. Gillham, The Waterloo & City Railway (Oakwood Press, 2001) p. 133
 R.L. Vickers, DC Electric Trains & Locomotives in the British Isles (David & Charles, 1986) p. 23