British Rail Class 143 Pacer

The BR Class 143 Pacer was a twenty-five-set variant of the Pacer family, built in 1985–86 by Walter Alexander Coachbuilders of Falkirk in conjunction with Andrew Barclay & Sons of Kilmarnock, who supplied the railway underframes. Like the Class 142, the 143 used a bus-derived body on a four-wheel railway chassis, but where the 142 used the Leyland National body, the 143 used a body built by Walter Alexander to their own design — a coachbuilder better known for its Scottish bus bodies — giving the class a slightly different profile and interior arrangement.

Each two-car set was powered by two Cummins diesel engines, one per car, driving through a hydraulic transmission. The Walter Alexander body was fitted to Andrew Barclay underframes, a Scottish combination that reflected the geography of the builders rather than any operational requirement. The sets were built for service in Wales and the West of England, working rural and secondary services on routes that had been worked by ageing first-generation DMUs.

The Class 143s shared the controversies of the wider Pacer family: rough riding, bus-type interiors, and difficult accessibility. They worked Wessex Trains and Arriva Trains Wales services until withdrawal between 2019 and 2021 as accessibility regulations and public pressure finally ended Pacer operation on the main network. Several have passed to heritage railways.