Metropolitan Railway "Camel-Back" Locomotives

The Metropolitan Railway in London began electrification of it's lines in the early years of the twentieth century. As well as electric multiple units, they also ordered a fleet of electric locomotives, the first ten being built by Metropolitan Amalgamated and used British Westinghouse equipment. The locomotives were built to haul passenger trains between Baker Street and Harrow-on-the-Hill [1][2], Great Western Railway trains from Edgware Road and Aldgate [3] and freight trains.

No. 1, notice the Baker Street destination board [1]


Information
Number built: 10
Built: 1906
Builder: Metropolitan Amalgamated / British Westinghouse
Motor: 4 Westinghouse 86 electric motors (600v DC fourth rail)
Power: 860 hp (640 kW)
Wheel arrangement: Bo-Bo

Unlike later locomotives bought by the Metropolitan Railway, this first batch had a central cab. This earned them the name "Camel-Backs". They were built with just one controller which proved to be operationally difficult for the driver, a second controller was added later. The locomotives were built as small as possible due to the cramped conditions at the termini. They used smaller electric motors than usual for the power output and employed forced ventilation from a fan installed in the cab [4]. The locomotives were fitted with improved electrical equipment in 1911. 

These locomotives, and the second batch of locomotives with British Thomson-Houston equipment, were replaced by new build locomotives by Metropolitan-Vickers in 1922 [5], originally the plan had been to rebuild the original locomotives but this proved to be uneconomic after one prototype so new locomotives were built instead reusing some electrical equipment from the earlier locomotives.
Plan of the locomotive [1]

Another view of No. 1 [3]

[1] "New Metropolitan Electric Locomotives", Street Railway Journal (Vol. XXVI No. 9) August 26 1905, p. 313 
[2] Chris Buck & Peter Lamb, The London Underground and it's Electrification, p. 5
[3] C.I. Horsey, "The Twenty Metropolitan-Vickers Locomotives One Hundred Years On - An Appendix to Their Story", Underground News (November 2019) p. 651
[4] "Electric Locomotives on the Metropolitan Railway", The Electrician (June 1 1906) p. 250
[5] Piers Connor, The London Underground Electric Train (Crowood Press, 2015) p. 43