British Railways Mark 1 - 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. Many of these features were later incorporated in the Mark 2 stock produced from 1964.