British Rail Mark 3

The British Rail Mark 3 is a type of passenger carriage developed in response to growing competition from airlines and the car in the 1970s. A variant of the Mark 3 became the rolling stock for the High Speed Train (HST).

Originally conceived as locomotive-hauled coaching stock, the first coaches built were for the prototype HST in 1972. Production coaches entered service between 1975 and 1988, and multiple-unit designs based on the Mark 3 bodyshell continued to be built until the early 1990s. Most of the surviving fleet of the Mark 3 and its derivatives were still in revenue service on the British railway network in 2020, however, as of 7 April 2021, 300 carriages have been sent for scrap.