BR Mk1 BCK brake composite coach in BR blue and grey livery.

The BCK was a useful coach, containing accomodation of first and second class passengers, plus a guards' office and small luggage van. In earlier times brake composite coaches were used as through coaches, so passengers did not have to change trains. In the blue/grey era the BCKs were used on lightly loaded trains, eg. winter services in the far north of Scotland, where the single coach provided all the passenger accomodations needed. Many were held as spares, as they could be used as a stand-in most other coaches.