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British Rail Class 122

Class of single-car diesel multiple units

Image credit is listed at the end of this article.

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).

01Construction

Table of orders and numbers
Lot No.TypeDiagramQtyFleet numbersNotes
30419Driving Motor Brake Second (DMBS)5392055000-55019
30420Driving Trailer Second (DTS)538956291-56299

02Operation

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. 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.

03Parcels 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.

04Usage 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Upon privatisation of Britain's railways, the Class 122 fleet has been withdrawn from normal service.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.

NumberPrevious numberUseDisposal/current useDate scrapped
TDB 97502355001Route learning carPreserved
TDB 97504255019Route learning car / SanditeStored on the Llanelli & Mynydd Mawr railway in Cynheidre, Carmarthenshire, set 960 015 / 55019 has been preserved.
TDB 97522755017Route learning carVic Berry2/89
97530955008Route learning carMayer Newman11/84
TDB 97531055010Route learning carMayer Newman6/84
TDB 97554055016Route learning carMC Metals7/93
TDB 97599455014Test & stores carVic Berry10/88
97599855013unknownMayer Newman3/82
TDB 97717755015Route learning carMC Metals7/90
TDB 97722355007Route learning carMC Metals6/91
97794155012Route learnerLoadhaul then EWS. Stored non-operational at Thornaby TMD from 1998. Purchased privately for preservation in 2009

05Preservation

"Bubble Cars" have proved popular for preservation on heritage railways.

Vehicle no. Unit no. Vehicle type Location Livery Comments
Original no. Departmental no.
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.

06Models

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.

Watch videos about British Rail Class 122Explainers and documentaries on YouTube (opens in a new tab)

Sources and credits

This article is adapted from the Wikipedia article British Rail Class 122, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.

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