The prototype was joined by another 20 two-car units which formed the Class 141 fleet.
The units were used mainly in Yorkshire, operating on predominantly suburban services.
They had a capacity of 94 passengers per two-car set, and two Leyland TL11 engines gave a total of 410 bhp (310 kW), resulting in a top speed of 75 miles per hour (121 km/h).

The 141s were built with standard Leyland National bodies, whose comparatively narrow width meant they could only be fitted with standard bus seating.
The later Pacers had widened body panels to allow increased seating.

The entire class underwent a technical upgrade in 1988 at the Hunslet-Barclay works in Kilmarnock.

The units were withdrawn from British Rail in 1997.
Many were sold to Islamic Republic of Iran Railways but have been withdrawn and are left in disused sidings in Iran, whilst a few remain in preservation.
The prototype was joined by another 20 two-car units which formed the Class 141 fleet. The units were used mainly in Yorkshire, operating on predominantly suburban services. They had a capacity of 94 passengers per two-car set, and two Leyland TL11 engines gave a total of 410 bhp (310 kW), resulting in a top speed of 75 miles per hour (121 km/h). 
The 141s were built with standard Leyland National bodies, whose comparatively narrow width meant they could only be fitted with standard bus seating. The later Pacers had widened body panels to allow increased seating.
The entire class underwent a technical upgrade in 1988 at the Hunslet-Barclay works in Kilmarnock. 
The units were withdrawn from British Rail in 1997. Many were sold to Islamic Republic of Iran Railways but have been withdrawn and are left in disused sidings in Iran, whilst a few remain in preservation.
Pacer (British Rail)