British Rail's first design of carriages were given the designation Mark 1. Initially, following Nationalisation in 1948, British Rail had continued to build carriages to the designs of the "Big Four" companies (the Great Western, Southern, London Midland & Scottish and London & North Eastern railways). The Mark 1 was intended to be the standard carriage design for use across all British Rail lines. It was also designed to be much stronger than previous designs to provide better protection for passengers in the event of an accident.

Construction

The design was used for hauled passenger stock, Multiple unit carriages and non-passenger carrying stock. For passenger stock, construction continued from 1951 to 1963, while Mark 1 design multiple units and non-passenger carrying stock continued to be built until 1974.

XP64

At the end of the production of hauled Mark 1 stock, came a series of experimental carriages known as the XP64 train. Externally they resembled Mark 1 stock and were built using standard Mark 1 underframes, but inside they included many new features, including pressure ventilation and new seating designs. Many of these features were later incorporated in the Mark 2 stock produced from 1964.

Criticism

After the 1988 Clapham rail accident, the Mark 1 design was criticised as it was no longer the best design for passenger protection, the Mark 3 design having excelled over it in this respect. In accidents like Clapham, where two units collided in line with each other, the Mark 1 design was prone to having the body shear away from the underframe, thereby crushing the passenger accommodation. The result of this criticism was a desire to end the use of Mark 1 stock on the mainline and, in the meantime, the use of special equipment to minimise the problem.

The equipment that was developed was called Cup and Cone, and while it was helpful, it was agreed that fitment to all stock would be too expensive in comparison with the safety benefits, when the stock was due to have only a short life and with improvements in signalling technology having reduced the likelihood of accidents where it would be most effective. As a result, Cup and Cone was never put into everyday use.

Withdrawal of the Mark 1 units was not practical in 1988; the youngest units were only 14 years old, which is just short of halfway through a train's expected life of 30 years. In addition, British Rail was still using multiple units with underframes that had been constructed before World War II, and these had priority for replacement.

Post_Privatisation

When Privatisation took place after 1994, only Connex South Eastern were given an extended franchise (15 years) in return for ordering new trains. Connex South Central and South Western Trains, the other major users of Mark 1 multiple units by that time, were not expected to order new trains. As a result, in 2000 Mark 1 units were still in use across most of the Southern Region with no new trains having been ordered.

Events since then have moved rapidly. Each of the three southern rail franchises have ordered hundreds of new multiple units of classes 171, 375, 376, 377, 444 and 450 to replace the remaining Mark 1 stock.

The use of Mark 1 stock on postal trains was curtailed when the Royal Mail decided to cease the use of rail to transport mail traffic. Thus, the problem of how to replace the large numbers of Mark 1 carriages on these services was answered.

Future

The final withdrawal of Mark 1s from daily mainline use is expected to take place in 2005, some 54 years since the design first entered service. Mark 1s continue to be used on special charter trains, but this use is also likely to be much reduced as Mark 3 coaches released from service by Virgin West Coast become available to replace them. This will leave preserved railways as the only place to ride on Mark 1 stock.