British Rail Class 121
Sixteen Class 121 single-car driving motor vehicles were built from 1960, numbered 55020-55035. These were supplemented by ten trailer vehicles, numbered 56280-289 (later renumbered 54280-289). They had a top speed of 70 mph, with slam-doors, and vacuum brakes. The driving motor vehicles were nicknamed "Bubble Cars" by some enthusiasts.
| British Rail Class 121 | |
|---|---|
 W55033 at the Colne Valley Railway in original green livery | |
| In service | 1960 - 2017 |
| Manufacturer | Pressed Steel Company |
| Family name | Bubble Car |
| Number built | 16 |
| Formation | 1 car per trainset |
| Operator | Arriva Trains Wales Network Rail |
| Specifications | |
| Car length | 64 ft 6 in (19,660 mm) |
| Width | 9 ft 3 in (2,820 mm) |
| Height | 12 ft 4 in (3,760 mm) |
| Maximum speed | 70 mph (110 km/h) |
| Weight | 38 tons |
British Rail Class 121 Media
121020 and 121034 at Bewdley in 2004.
