118 three-car units (59 trains) built by GEC Alsthom-Metro-Cammell
between 1996 and 1998, and first entered service in December 1997.
An additional 4 seven-car trains were built in 2005 for a total of 126
units (63 trains), and the original trains were lengthed to 7 cars each
(additional trailers numbered 966xx and 967xx).
Each seven-car train is formed of a four-car unit (odd numbered) and a
three-car unit (even-numbered).
63 four-car units are formed of a driving motor car (DM), 2 trailers (T),
and an uncoupling non-driving motor car (UNDM). These cars are numbered
960xx-962xx-966xx-964xx and 961xx-963xx-967xx-965xx. All cars in these
units are odd-numbered, and face Stratford.
63 three-car units are formed of a driving motor car (DM), a trailers (T),
and an uncoupling non-driving motor car (UNDM). These cars are numbered
960xx-962xx-964xx and 961xx-963xx-965xx. All cars in these units are
even-numbered, and face Stanmore.
All even-numbered three-car units between 96080 and 96118 inclusive carry
deicing equipment in their third trailer car (968xx or 969xx).