Balfour Beatty Mk1 BSK Staff CHOR R40213 Hornby Balfour Beatty, Mk1 BCK, Staff Coach, BDC 977165 Era 9 2022 Catalogue The first standardised railway carriage design built by British Railways, the Mark 1 Coach introduced in 1951 continued to be produced until 1963, and even later in the form of multiple units and non passenger stock. Mk1 Coaches were built in various places including Derby, Doncaster, Eastleigh, Swindon, Wolverton and York.