As we know the history of the design and operation of diesel – or is it oil-engine powered? – multiple unit trains can be traced back well beyond nationalisation in 1948, although their use was not widespread in Britain until the mid 1950s. Today, we can see their most recent developments in the fixed formation sets operated over long distance routes on today’s networks, such as those of the Virgin Voyager design.
It can be argued that the real ancestry can be seen in such as the experimental Michelin railcar and the Beardmore 3-car unit for the LMS in the 1930s, and the various streamlined GWR railcars of the same period. Whilst the idea of a self-propelled passenger vehicle, in the shape of numerous steam rail motors, was adopted by a number of the pre-grouping companies from around the turn of the 19th/20th century. (The earliest steam motor coach can be traced to 1847 – at the height of the so-called ‘Railway Mania’.).
First of the “modern” multiple unit designs were built at Derby Works and introduced in 1954, as the ‘lightweight’ series, and until 1956, only BR and Metropolitan Cammell were constructing these new units. In 1956/7, new designs from several builders took to the rails, including Birmingham RC&W Co., Cravens, Park Royal, and the Gloucester Railway Carriage & Wagon Co.
It was thought that these new self-propelled railcars would replace non-corridor locomotive hauled stock on some suburban and country/rural lines, and in specific areas on a trial basis, in order to reduce running costs on services that were still operational. In some areas they were intended to provide additional services, so adding to, rather than reducing costs. They appeared at the time when the initial, faltering steps, were being taken to modernise the rail network and its stock. However, perhaps in some ways surprisingly, the opportunity was not taken to introduce any new techniques in design or construction methods, and the majority of the early types were built on a traditional 57ft 0ins underframe.
Whilst the general principles of design were essentially the same for all multiple-units, whether produced by BR or contractors, the first Gloucester built units had a curious and uniquely profiled body. In addition they represented the earliest use of an integral structure, with cold drawn, square section steel tube framing. Later vehicles from Gloucester were however, closer in appearance to the later Derby ‘lightweight’ form. All were described as ‘low density stock’. Today we might suggest that this greater space and leg room for passengers was designed more with the outer suburban, or rural routes in mind.
More than 40 of these two-car units were ordered by the British Transport Commission (BTC) in 1955, with delivery starting in late 1957. The majority of these were intended for service on the Scottish Region, and a handful on the London Midland Region. In the following year, 1958 saw the introduction on the Western Region of 10 single unit railcars, with nine trailer cars and a three-car cross-country set. The final contribution from the Gloucester company was a batch of 10 motor parcels vans for the Western and London Midland Regions, which appeared from 1959.
Changes to operations brought in under Beeching initially, and later structural changes as the “sectorisation” of British Rail sought to improve its economic and commercial success, with reduced traffic options for these earliy multiple units was their ultimate downfall. The rail network landscape had changed very dramatically since they were first ordered back in 1956, but many survived until the mid 1980s, and a few even into the ‘privatisation’ era. The designs for the most part met the requirements of the day, and even a little beyond, but by the 1990s, they were a thing of the past.
The factory where these and many others were built closed in 1986, with loss of jobs and rail engineering skills, but the company’s 1st generation DMUs for the BR Modernisation Plan of the 1950s still have a great role to play in the 21st Century.
Clicking on the image below will take you to a more detailed review of the class.