10 two-car units (5 trains) built between 1991 and 1994, and first
entered service in July 1993.
The trains were originally known as Class
482 by British Rail until April 1994, when the line and trains were
transfered to London Underground and the trains were referred to as the
1992 stock.
Each four-car train is formed of 2 two-car units. Every odd-numbered unit
must be coupled with an even-numbered unit. All coupled unit numbers are
sequential.
Each unit is formed of a driving motor car (DM) and a non-driving motor
car (NDM). These cars are numbered 655xx-675xx.