Based on the single car railbus prototypes, the class 140 was built to BR's then stringent regulations regarding crashworthiness and resistance to end loading in 1980. This meant that it lost its lightweight 'bus on a wagon' look and was much more substantial.
The original traction power train consisted of a Leyland TL11 200 HP engine, a Self-Changing Gears mechanical automatic gearbox and a Gmeinder final drive unit on each car driving only one axle.
The sole member of the class, No. 140001, formed of cars 55500+55501, has been preserved and is currently at the Keith and Dufftown Railway. The Class 140 formed the basis of the design of the production Pacer sets of Class 141 introduced in 1984 and Class 142 introduced in 1985.
This unit is currently at Dufftown Station. It is currently slowly being restored to its former state by volunteers at the railway.
140001 at Shrewsbury between driver training runs on the Central Wales line on 4 December 1981.