The British Rail Classes 101 and 102 diesel mechanical multiple units were built by Metro-Cammell at Washwood Heath in Birmingham, England from 1956 to 1959, following construction of a series of prototype units. These classes proved to be some of the most successful and longest-lived of BR's First Generation DMUs, second in longevity only to the Class 121, with the final five units being withdrawn on 24 December 2003. The oldest set was, by then, just over 47 years old. Background In 1954, British Rail published a Modernisation Plan to streamline the railway network, bringing it up to date in comparison to European standards. Steam power would be phased out in favour of diesel powered railcars and locomotives, and projects were put out to tender. BR hoped that by replacing steam with DMUs, costs would be reduced sufficiently to make rural lines viable. Since there was no time for BR to issue a standard specification, train builders were invited to submit plans on the understanding that the units could be built and put into service quickly. Having gained experience with early lightweight DMUs, Metro Cammell won a contract and put the Class 101 into production. The type featured a steel chassis with an aluminium body to reduce weight. Five orders for batches were placed for the type. Metro-Cammell advertised their new train highlighting the wide availability and modern features the 101 offered. Demand was so high that at one point four cars per week were rolling off the Washwood Heath production lines. The trains underwent testing on the Sutton Park line near the works from 1956, before the sets were released to BR. The 101s came in two, three or four car units, with two driving carriages one or two of which were powered by 11.3 litre BUT six cylinder diesel engines with epicyclic gearboxes. Being a first generation DMU, they were a prime example of a slam door train. They had a top speed of . Operations The 101 DMU fleet was vast with 527 101s and 106 of the related Class 102s being built. The two types were distinguished by the type of engine fitted, but were eventually classified together as Class 101s only. In all, 760 individual vehicles were built in total, 465 were for the Eastern Region and North Eastern Region, 159 for the Scottish Region and 139 for the London Midland Region. In the mid-1970s,