The British Rail

British Rail

British Railways , which from 1965 traded as British Rail, was the operator of most of the rail transport in Great Britain between 1948 and 1997. It was formed from the nationalisation of the "Big Four" British railway companies and lasted until the gradual privatisation of British Rail, in stages...

 Class 150 "Sprinter"

British Rail brand names

British Rail was the brand image of the nationalised railway owner and operator in Great Britain, the British Railways Board, used from 1965 until its breakup and sell-off from 1993 onwards....

 diesel multiple unit

Diesel multiple unit

A diesel multiple unit or DMU is a multiple unit train consisting of multiple carriages powered by one or more on-board diesel engines. They may also be referred to as a railcar or railmotor, depending on country.-Design:...

s (DMUs) were built by BREL

BREL

British Rail Engineering Limited , was the railway systems engineering division of British Rail, until the design and building of trains in the UK was privatised in 1993. On 31 October 1969, the company was incorporated as British Rail Engineering Limited.-Main products:The vast majority of BREL's...

 from 1984-87. A total of 137 units were built in three main subclasses, replacing many of the earlier first-generation "Heritage" DMUs.
At the beginning of the 1980s, British Rail

British Rail

British Railways , which from 1965 traded as British Rail, was the operator of most of the rail transport in Great Britain between 1948 and 1997. It was formed from the nationalisation of the "Big Four" British railway companies and lasted until the gradual privatisation of British Rail, in stages...

 (BR) had a large fleet of ageing "Heritage" DMUs built to many different designs in the late 1950s and early 1960s. Some of the more reliable types were retained and refurbished.