London Underground carriages thought to be a District Railway first class, but now thought likely to be a cutdown Metropolitan Railway eight-wheeler. A Jubilee Stock first class carriage was restored to carry passengers in January 2013 during the Met's 150th anniversary celebrations. The Bluebell Railway has four 1898–1900 Ashbury and Cravens carriages, and a fifth, built at Neasden, is at the London Transport Museum. The Vintage Carriages Trust has three preserved Dreadnought carriages. London Underground carriages The London Underground opened in 1863 with gas-lit wooden carriages hauled by steam locomotives. The Metropolitan and District railways both used carriages exclusively until they electrified in
British Rail Class 501 jointly operated with London Underground's Bakerloo and District Lines. In 1970 the trains were converted to 3rd rail only operation, although the 4th rail was retained on sections of line which are shared with London Underground trains. The original electric scheme on these lines was at 630V DC, which was actually supplied at +420V in the outer electric rail and -210V in the centre one, a total potential difference of 630V. This was the same system as used at the time (and still employed today) by London Underground, and allowed Underground trains to run over the lines, from Queens Park