British Rail Class 313 electric multiple units were built by BREL at York Works from 1976 to 1977, thus the first second-generation EMUs to be constructed for British Rail. They were capable of both drawing power via 25 kV AC overhead, or 750 V DC third-rail. They were the first units in Britain to have fully automatic couplers which allowed both physical coupling and also the connection of control electric and air supplies to be carried out without the driver's need to leave the cab. Their passenger seats were also an improvement on former types.