# British Rail Class 122

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).

## Construction

Table of orders and numbers :
| Lot No. | Type | Diagram | Qty | Fleet numbers | Notes |
| 30419 | Driving Motor Brake Second (DMBS) | 539 | 20 | 55000–55019 | |
| 30420 | Driving Trailer Second (DTS) | 538 | 9 | 56291–56299 | |

## Operation

The Class 122s were built mainly for use on the London Midland Region of British Railways, although some were 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. 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).
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.

## Usage after passenger service

Upon privatisation of Britain's railways, the Class 122 fleet has been withdrawn from normal service. However several units were operated by EWS and Network Rail (previously Railtrack) in departmental service, reclassified as Class 960.
| Number | Previous number | Use | Disposal/current use | Date scrapped |
| TDB 975023 | 55001 | Route learning car | Preserved |
| TDB 975042 | 55019 | Route learning car / Sandite | Stored on the Llanelli & Mynydd Mawr railway in Cynheidre, Carmarthenshire, set 960 015 / 55019 has been preserved. | |
| TDB 975227 | 55017 | Route learning car | Vic Berry | 2/89 |
| 975309 | 55008 | Route learning car | Mayer Newman | 11/84 |
| TDB 975310 | 55010 | Route learning car | Mayer Newman | 6/84 |
| TDB 975540 | 55016 | Route learning car | MC Metals | 7/93 |
| TDB 975994 | 55014 | Test & stores car | Vic Berry | 10/88 |
| 975998 | 55013 | unknown | Mayer Newman | 3/82 |
| TDB 977177 | 55015 | Route learning car | MC Metals | 7/90 |
| TDB 977223 | 55007 | Route learning car | MC Metals | 6/91 |
| 977941 | 55012 | Route learner | Loadhaul then EWS. Stored non-operational at Thornaby TMD from 1998. Purchased privately for preservation in 2009 | |

## Preservation

"Bubble Cars" have proved popular for preservation on heritage railways.
| Vehicle no. | Vehicle no. | Unit no. | Vehicle type | Location | Livery | Comments |
| Original no. | Departmental no. | Unit no. | Vehicle type | Location | Livery | Comments |
| 55000 | - | 122100 | DMBS | South Devon Railway | BR Green | - |
| 55001 | 975023 | L101 | DMBS | East Lancashire Railway | BR Blue | - |
| 55003 | - | P103 | DMBS | Gloucestershire Warwickshire Railway used to be Mid Hants Railway. | BR Green | First preserved DMMU to gain main line certification. |
| 55005 | - | P105 | DMBS | Battlefield Railway | BR Blue/Grey | - |
| 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. |
| 55009 | - | P109 | DMBS | Great Central Railway | BR Green | Non operational |
| 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 due to the driver's fault while working on the Stourbridge Town branch line so the one end is not the end which was surviving from the beginning. The rear end was scrapped. |
| 55019 | 975042 | 960015 | DMBS | Llanelli and Mynydd Mawr Railway | Network Rail Yellow | Formerly owned by Network Rail, W55019, 122 019; 8th and last Class 122 brought into preservation. |

## 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.