Built by Metropolitan-Cammell Carriage & Wagon Company and introduced in October 1956, they were numerically the largest class of BR diesel multiple units. They were the start of a revolution in branch line passenger transportation which lead to a speedy reduction in the number of tank engines kept by British Railways. While the Eastern Region received the first batch, subsequent batches went to all five of the other regions. The ran in 2, 3 and 4 car formations and the trailers were interchangeable with those of the Class 111 The class featured in the DMU refurbishment programme in the 1970s and these were turned out in white and blue livery. A large number of the units continue to give good service on preserved lines.

Bachmann have produced both 2-car and 3-car formations for their Graham Farish N gauge range and both types are reviewed here. They are superbly detailed with separately attached exhaust pipes and under floor detail. There is seating inside where the models motor does not intrude and even the cab interiors appear to be detailed. Each has a 6-pin DCC socket fitted with under-floor micro switches to turn lights on and off. There are 3 different styles of cab, and roof variations have been modelled. The models have brass flywheels, NEM couplings and come with a pack of bufferbeam detail to add.

The 2-car sample (371-503) is in blue and grey, with 'Express Parcels' on its sides and Red Star branding. This represents one of three 2-car units that were allocated to the Parcels Sector in 1987. They were withdrawn from service in 1989. The model's cars are numbered E53255 and E53233. Three other 2-car Class 101 DMUs are also available. These are in green with speed 'whiskers' (371-500), Regional Railways blue (371-501) and BR blue (371-502).

There are two 3-car units to review out of three issued so far. In BR Brunswick Green with speed 'whiskers' (371-510) we have cars M50312, M59123 and M50330. This the livery in which they ran when first introduced.