zBR, Mk4 Standard, Coach CHOR R40156A Hornby BR, Mk4 Standard, Coach C Era 8 Built at Metro Cammells Washwood Heath factory, 314 Mk4 coaches were produced between 1989 and 1992. They were built specifically for use on the newly electrified East Coast Main Line, along with hopes that a second order for the West Coast Main Line would be placed at a later date, although this second order never transpired. Mk4 coaches featured many improvements over the Mk3s such as push button