The British Rail Class 104 diesel multiple units were built by Birmingham Railway Carriage and Wagon Company from 1957 to 1959.
The first units ordered were for the London Midland Region, with the majority of the class for use in North West of England with sets also in Tyneside (being made redundant by the opening of the Tyne & Wear Metro in 1980). In the mid-1980s a few units reallocated to Scotland, with one unit being repainted in a unique maroon and white livery for services to Oban - it became known as the "Mexican Bean". Other vehicles spent time in London and the last vehicles could be found there in the early 1990s.
The class was gradually taken of service from the early 1980s. The final vehicles were withdrawn in 1995.