Mark 1 Coach

British Railways Mark 1 was the family designation for the first standardised designs of railway carriages built by British Railways. Following nationalisation in 1948, BR had continued to build carriages to the designs of the "Big Four" companies (the Great Western, Southern, London Midland and Scottish and London and North Eastern railways), and the Mark 1 was intended to be the standard carriage design for use across all lines, incorporating the best features of each of the former companies' designs. It was also designed to be much stronger than previous designs, to provide better protection for passengers in the event of a collision or derailment. The Mk 1 coaches were built in two distinct tranches: the early vehicles (1951–60) and the 'Commonwealth' stock (named from the type of bogie used) from 1961 onwards.

XP64
Near the end of the production of hauled Mark 1 stock came a series of eight experimental carriages known as the XP64 set. Three Corridor Firsts, two Corridor Seconds, and three Tourist Second Opens were built by Derby Carriage Works in 1964. Externally they resembled Mark 1 stock with the addition of a cosmetic cover over the solebars of the standard Mark 1 underframes, but inside they included many new features, including pressure ventilation, new seating designs and wider bi-fold doors.undefined Many of these features were later incorporated in the Mark 2 stock produced from 1964.