The BR Standard Mk.3 coach was introduced to traffic between 1975 and 1988, on both high speed and locomotive hauled services and quickly became a regular sight on Britain's main line services. In 2014, First Great Western refurbished its Mk.3 first class carriages with interiors that dropped the First Great Western branding in favour of a new GWR logo and the whole company was subsequently rebranded as Great Western Railway (GWR) on 20 September 2015, with rolling stock featuring a dark green livery that echoed that of the former Great Western Railway.

Each model measures 303mm in length.