Mk2A BFK W17069 at Birmingham New Street in June 1984. © Steve Jones
The Mark 2 family of railway carriages are British Rail's second generation of coaching stock. They were built by British Rail workshops between 1964 and 1975 and were of a steel construction. The Mark 2 has a semi-integral construction, giving it more strength than a Mark 1 in the event of an accident. A key driver of the changed construction method was to overcome the serious corrosion problem point in the Mark 1 at the base of the body, where it was attached to the underframe. The original Mk2s featured pressure ventilation, wood panelling and vaccuum brakes so that they could work with Mk1 sotck. Mk2As were fitted with air-brakes and different gangways. Mk2B coaches omitted the centre door and had wide wrap-aroind doors at the ends. Finally the Mk2Cs featured a lowered ceiling with provision for air conditioning that wasn't fitted. Later, further variations were produced covering D, E and F variants, which are detailed elsewhere on our site. The Mark 2 coach was one of the mainstays of the InterCity network, but new rolling stock introduced in the post-privatisation era has resulted in most being withdrawn.
(Information provided via Wikipedia)