British Rail Class 122

British Rail Class 122 Bubble Car
Class 122, no. 55006, at Bewdley on the Severn Valley Railway 2004, whilst taking part in the Railcar 50 event. This unit is painted in the second version of BR Green livery, and is preserved on the Ecclesbourne Valley Railway.
Interior of W55000 on the South Devon Railway
In service1958–1995
ManufacturerGloucester RC&W
Family nameFirst generation
ReplacedSteam locomotives and carriages
Number built20 motor, 9 trailer
Number preservedDMBS: 8
FormationSingle car
Diagram
  • DMBS: 539
  • DTS: 538
Fleet numbers
  • DMBS: 55000–55019
  • DTS: 56291–56299
Capacity
  • DMBS: 65
  • DTS: 95
OperatorBritish Rail
Depots
Lines served
Specifications
Car body constructionSteel
Car length64 ft 0+1⁄2 in (19.52 m)
Width9 ft 3 in (2.82 m)
Height12 ft 8+1⁄8 in (3.86 m)
DoorsSlam
Articulated sectionsSingle car (2)
Maximum speed70 mph (113 km/h)
Weight
  • DMBS: 36 long tons (81,000 lb; 37 t)
  • DTS: 29 long tons (65,000 lb; 29 t)
Prime moverTwo BUT (AEC) then BUT (Leyland) of 150 hp (110 kW) (both types)
Power output300 hp (220 kW)
TransmissionStandard mechanical
Safety systemAWS
Multiple working■ Blue Square
Track gauge4 ft 8+1⁄2 in (1,435 mm)

The British Rail Class 122 diesel mechanical multiple units were built by Gloucester RC&W in 1958. Twenty single-car, double-ended driving motor vehicles, nicknamed "Bubble Cars", were built, numbered 55000–55019. These were supplemented by nine single-ended trailer vehicles, numbered 56291–56299 (some of which were later renumbered into the 54291–54299 block).

Operation

The Class 122s were built for use on the Western Region of British Railways, the initial allocations being: 81D Reading – three DMBS; 81C Southall – nine DMBS and six DTS; 84E Tyseley – eight DMBS and three DTS. Eleven DMBS and five DTS that were allocated to Tyseley depot passed to the London Midland Region when the regional boundaries were changed in 1963; some were subsequently also used in Scotland. They were used on a variety of lightly used lines, many of which were closed during the Beeching Axe in the 1960s including the ex-LSWR lines in West Devon and North Cornwall.

During the 1990s, refurbished Class 122 units were used on the Cornish branches between Liskeard and Looe and St Erth and St Ives.

Parcels conversion

In 1968, three cars (55013–55015) were converted for use on the Scottish Region to carry parcels traffic and were reclassified Class 131, though the vehicles themselves were not renumbered. The converted vehicles were given the TOPS classification DXV.

Preservation

Vehicle no. Unit no. Vehicle type Location Livery Comments
Original no. Departmental no.
55006 - P106 DMBS Ecclesbourne Valley Railway BR Green Collided with the buffers at the Stourbridge Town terminus of the Stourbridge Town branch line on 21 April 1989 after the driver was distracted by trespassers.
55012 977941 DMBS Weardale Railway BR Green Joined the fleet on a permanent basis in December 2013 after visiting for contract repairs Took part in Railcar 50 in 2004. Required a modification back to single car unit after this D.M.B.S collided into the Stourbridge Town station buffer on 2 April 1977.

Models

Dapol has released models of the Class 122 railcar in both O gauge and OO gauge in a variety of liveries.

In 2012, Dapol introduced a British N gauge model of the Class 122 in both BR blue and BR blue and grey liveries.

In 2025, Heljan announced they would release a TT scale model of the Class 122 in various liveries, due for release in 2026.

References

  1. ↑ British Rail Locoshed book. Ian Allan. 1981. p. 50. ISBN 0-7110-1112-5.
  2. 1 2 3 Hemming 1978, p. 12.
  3. ↑ British Rail Locoshed book. Ian Allan. 1979. p. 48. ISBN 0-7110-0931-7.
  4. 1 2 Mitchell 1994, p. 25.
  5. ↑ Heginbotham, Stephen (2010). Cornwall's Railways Remembered. Halsgrove. pp. 51–52. ISBN 978-0-85704-005-3.
  6. 1 2 Mitchell 1994, p. 33.
  7. ↑ Mitchell 1994, p. 89.
  8. 1 2 Mitchell 1994, p. 136.
  9. ↑ Butcher, Roger (November 1993). Departmental Coaching Stock (5th ed.). Southampton: South Coast Transport Publishing. pp. 60, 75. ISBN 1-872768-10-5.
  10. ↑ Grindlay, Jim (June 2008). British Railways Motive Power Allocations 1948-1968 Part Seven: Diesel Railcars & Multiple Units (1st ed.). Ayr: Transport Publishing Ltd. pp. 63, 74. ISBN 978-0-9544264-7-7.
  11. ↑ "Class 122 Gloucester RC&W Single / 2-car DMUs". Railcar. Retrieved 10 August 2026.
  12. ↑ "Motive power miscellany". Railway World. Vol. 32, no. 376. Shepperton: Ian Allan. September 1971. p. 418.
  13. ↑ Bowles, LJ; Mallaband, P (1978). Coaching stock of British Railways. RCTS. p. 50. ISBN 0-901115-44-4.
  14. 1 2 Butcher, Clive (1998). The Railways of Stourbridge. Usk: Oakwood Press. pp. 175–181. ISBN 0-85361-533-0.
  15. ↑ "Dapol Class 122 | Hornby Magazine". Archived from the original on 28 December 2016.
  16. ↑ Burkin, Nigel (December 2012). "Gloucester Class 122 for 'N' gauge". Hornby Magazine. No. 66. Hersham: Ian Allan Publishing. pp. 80–81. ISSN 1753-2469. OCLC 226087101.
  17. ↑ "Heljan launches UK outline 'TT:120' range".

Sources

Further reading