Twenty single-car, double-ended driving motor vehicles, nicknamed "Bubble Cars", were built, numbered 55000–55019.

[6] Routes served included the Stourbridge Town and St Albans Abbey branch lines, as well as local services between Dundee and Arbroath.

(The similar Pressed Steel Company built Class 121 single units were also used on the Western Region).

[4][8] In 1968, three cars (55013–55015) were converted for use on the Scottish Region to carry parcels traffic[10] and were reclassified Class 131, though the vehicles themselves were not renumbered.

However several units were operated by EWS and Network Rail (previously Railtrack) in departmental service, reclassified as Class 960.