The British Rail Mark 5 is the designation given to locomotive-hauled rail carriages built by Spanish manufacturer CAF for operation with Caledonian Sleeper.

Construcciones y Auxiliar de Ferrocarriles is a Spanish publicly listed company which manufactures railway vehicles and equipment and buses through its Solaris Bus & Coach subsidiary. It is based in Beasain, Basque Autonomous Community, Spain. Equipment manufactured by Grupo CAF includes light rail vehicles, rapid transit trains, railroad cars and locomotives, as well as variable gauge axles that can be fitted on any existing truck or bogie.