374-997A BR Mk3 'Night Riviera' 2-Coach Pack GWR Green (FirstGroup) No.10584 & No.12142 - Pack BThe British Railways Mk3 was the third generation of BRs standard design of main line coaching stock. Whilst the look of the Mk3 may be considered an evolution of the later series Mk2s, the modern features of the Mk3 from the disc brakes to the secondary air suspension between the body and bogies and the increased length of almost 10 feet clearly set the two types apart. Built from 1972, the first prototype vehicles were used as part of the Prototype