BR Dptmntl ex-Mk1 1st OpenHOR R40342 Hornby BR Departmental, ex Mk1 First Open, 3068 975606 Era 8 2022 Catalogue The first standardised railway carriage design built by British Railways, the Mk 1 Coach introduced in 1951 could be found across Britain's railway network and continued to be produced until 1963, and even later in the form of multiple units and non passenger stock. Along with being widely deployed, Mk1 Coaches were built in various places including Derby,