Circle route
The District Railway used electric locomotives on electrified underground lines that were exchanged for steam locomotives to continue over unelectrified track. Ten were built in 1905, and these operated in pairs, initially used to haul London and North Western Railway passenger trains on their Outer Circle route between Earl's Court and Mansion House. From 1910 trains from the London, Tilbury and Southend Railway were extended over the District, the steam locomotives being exchanged for electric ones at Barking. These locomotives were scrapped after the service was withdrawn in 1939.