London Underground B Stock

B Stock was built in 1905 for the electrification of the District Railway's Ealing/Hounslow - Whitechapel line and the branches to High Street Kensington and South Acton [1]. Working to a common design, four hundred and twenty driving cars and trailers were built by a number of manufacturers. Of each seven car set three cars were powered (400hp each) [2].
District Railway B Stock train [2]

Information
Number built: 420 (60 7-car sets)
Built: 1905
Builder: Brush Traction, Metropolitan Amalgamated,
Les Ateliers de Construction du Nord de la France
Motor: British Thomson-Houston GE69 electric motors
(600v DC fourth rail)
Power: 1, 200 hp (895 kW)
Formation: Driving Motor (DM) + Trailer (T) + T +
Middle Motor (MM) + T + T + DM

As built the B Stock had compressed air operated doors under the control of a single gateman, pioneering the use of air doors on the London Underground. However these doors proved unsuccessful in use, one problem being there was no detection system to make sure the doors had closed properly other than the gateman's eyeballs! The door edges were copper lined not rubber and the District Railway was soon getting a bad press due to the number of injuries and torn clothing of passengers. The District Railway reverted back to manual doors in 1908.

The cars were made from wood with steel underframes with General Electric motors and BTH type M controllers [3]. The so-called Motor Middle cars had driving cabs at each end to allow the trains to be reduced in size during quiet periods, some were also used as single cars on branch shuttles. The trains had a mixture of first and third class accommodation.

Some trailers were scrapped in the early 1920s due to their poor condition [4]. Some remaining B Stock trains were later reconditioned and redesignated H Stock trains, these remained in service until 1946. The final few B Stock cars remained in departmental use until 1950 before being scrapped.
Side view of B Stock car [5]

Interior [5]

B Stock car on delivery [5]

[1] Brian Hardy, Underground Train File: Surface Stock 1933-1959 (Capital Transport, 2002) p. 24 
[2] "Electrification of the District Railway", Practical Engineer (October 6 1905) p. 551 
[3] Piers Connor, The London Underground Electric Train (Crowood Press, 2015) p. 43
[4] Hardy p. 26
[5] S.B. Fortenbaugh, "The Electrification of the London Underground Electric Railway Company System", Street Railway Journal (Vol. XXV No. 9, March 4 1905) p. 388