British Rail

British Rail

British Railways , which from 1965 traded as British Rail, was the operator of most of the rail transport in Great Britain between 1948 and 1997. It was formed from the nationalisation of the "Big Four" British railway companies and lasted until the gradual privatisation of British Rail, in stages...

's third design of standard carriage was designated 'Mark 3' (also described as Mark III), and was developed primarily for the InterCity 125 High Speed Train

InterCity 125

The InterCity 125 was the brand name of British Rail's High Speed Train fleet. The InterCity 125 train is made up of two power cars, one at each end of a fixed formation of Mark 3 carriages, and is capable of , making the train the fastest diesel-powered locomotive in regular service in the...

 (HST). The vehicle was also developed as a conventional locomotive-hauled coach for the West Coast Main Line

West Coast Main Line

The West Coast Main Line is the busiest mixed-traffic railway route in Britain, being the country's most important rail backbone in terms of population served. Fast, long-distance inter-city passenger services are provided between London, the West Midlands, the North West, North Wales and the...

 (WCML) northern electrification scheme - this was the first Mark 3 derivative to enter revenue service, in 1975, with the definitive HST version appearing a year later.