The fully automated trains may not have drivers, Transport for London are planning to issue an Invitation to Tender at some point potentially for up to 27 new trains for the Jubilee and Northern lines.Tf L want up to 10 trains for the Jubilee line and up to 17 trains for the Northern line (5 for the extension to Battersea and 12 to increase frequencies).Until the early 1960s an electric locomotive was exchanged for a steam locomotive on Metropolitan line services beyond Rickmansworth.The Victoria line opened in the late 1960s using Automatic Train Operation (ATO), and the last trains ran with a guard in 2000.The earlier railways had electrified the underground sections of their lines by 1907.Pneumatic sliding doors were introduced on tube trains in 1919 and sub-surface trains in the late 1930s.The first services were run by the Metropolitan Railway, but in 1871 the District Railway began running its own services with locomotives were identical to the Metropolitan Railway A Class already in use.Twenty were supplied initially, Concern about smoke and steam in the tunnels led to trials before the line opened with an experimental "hot brick" locomotive nicknamed Fowler's Ghost.
The older sub-surface trains have recently been replaced by new air-conditioned S Stock, and the replacement of trains on the Bakerloo and Piccadilly lines is under consideration.
Stock on sub-surface lines is identified by a letter (such as S Stock, used on the Metropolitan line), while tube stock is identified by the year in which it was designed (for example, 1996 Stock, used on the Jubilee line). The Deep tube programme (DTP) originally covered the replacement of the trains and signalling on the Bakerloo and Piccadilly lines, and had been expanded to cover rolling stock requirements arising from the planned extension of the Northern line to Battersea, the eventual replacement of Central line trains and proposed increased service frequency on the Northern and Jubilee lines.
The EVO tube concept design, a lighter articulated train with walk through cars, was introduced early in 2011.
From the early 1940s these were replaced by ex Great Central Railway locomotives, now classified LNER Class A5.
These were again replaced in 1948 by LNER L1s, and ten years later, when the joint line was transferred to British Railway's London Midland Region, former LMS locomotives replaced the L1s.