175 three-car units (87½ trains) built between 1974 and 1977, and first
entered service in July 1975. One unit (166) has been withdrawn and scrapped.
Each six-car train is formed of 2 three-car units. Every odd-numbered unit
must be coupled with an even-numbered unit.
151 three-car units are formed of a driving motor car (DM), trailer (T), and an
uncoupling non-driving motor car (UNDM). These are numbered in the 1xx (1xx-5xx-3xx)
and 2xx (2xx-6xx-4xx) ranges. All even-numbered units between 206
and 252 (inclusive) carry deicing equipment in their trailer car.
21 three-car units are double-ended, meaning they have a cab at both ends. These
are formed DM-T-DM, and are numbered in the 8xx range (8xx-6xx-8xx).
2024 stock
94 nine-car units are being built by Siemens as part of the Piccadilly Line Upgrade
to enter service starting from 2025, however the contract allows for an additional
18 units to be ordered for a total of 112 units.
Each train will be formed of a single unit, formed of 2 driving motor cars (DM),
4 intermediate cars without bogies (IM), and 3 key motor cars with two bogies but
no cab (KM); in the formation DM-IM-KM-IM-KM-IM-KM-IM-DM.
Cars are numbered 38xxx-39xxx-40xxx-41xxx-42xxx-45xxx-47xxx-48xxx. Car numbers
43xxx (IM) and 44xxx (KM) are missing to accomodate a longer 11-car variant of
the 2024 stock that may be used on the Central line in the future.