British Rail Mark 4

The British Rail Mark 4 is a class of passenger carriages built for use in InterCity 225 sets on the East Coast Main Line between King's Cross, Leeds and Edinburgh. A small build compared with the Mark 2 and Mark 3 designs, 314 Mark 4 coaches were built between 1989 and 1992 by Metro-Cammell's Washwood Heath factory. Swiss SIG BT41A bogies were chosen in place of BREL T4 bogies when BREL could not give commercial guarantees on the lateral ride comfort required for 140 mph (230 km/h) running, and the Mark 4 is derived from the Class 156. Between October 2003 and November 2005 Bombardier Transportation rebuilt and refurbished the carriages for GNER under Project Mallard. Withdrawals began in 2019, with some sold for further use with Transport for Wales.