British Rail Class 121

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Chiltern Railways operate a single Class 121 "Bubble Car" on Aylesbury to Princes Risborough shuttles. Set 121020 is seen away from its normal haunts, at Bewdley on the Severn Valley Railway on 15th October 2004, whilst taking part in the Railcar 50 event.

The British Rail Class 121 diesel multiple units were built by Pressed Steel in 1960.

[edit] Description

Sixteen single-car driving motor vehicles were built, 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.

[edit] Current operations

Upon privatisation of Britain's railways, the Class 121 fleet was only operated by one passenger company, namely Silverlink, with several more units in departmental duties with Railtrack. There are two examples left in revenue-making service.

[edit] Arriva Trains Wales

In 2006 unit 121032 was purchased by Arriva for use on the Cardiff Bay Shuttle. The unit has been repainted into Arriva colours and was hauled to Wales in June 2006 to enter service in July. The unit finally entered service on 17 August 2006 but was withdrawn 2 days later due to a major problem with the engine. The unit re-entered service on the Cardiff Bay line on 14 September 2006.

[edit] Chiltern Railways

In 2003, Chiltern Railways surprised many by reintroducing "Heritage" diesel multiple units on its Aylesbury to Princes Risborough shuttle service. For this purpose, unit 121020 (vehicle 55020) was purchased from Network Rail, and heavily refurbished to allow it to operate passenger services. It was repainted into Chiltern Railways blue livery. The introduction of this unit allowed the release of a Class 165 "Turbo" unit for refurbishment. This unit has been fitted with secondary (magnetic) door locking and other safety features, and thus is exempt from the 30 November 2005 deadline for the withdrawal of all Mark 1 vehicles.

Departmental unit, 960011 stored at the National Railway Museum.

[edit] Network Rail

Network Rail (NR) operates a small fleet of former Class 121 vehicles for various departmental roles. These have been reclassified as Class 960 departmental units. Duties include route learning, video surveying of track, Severn Tunnel emergency tunnel evacuation and sandite application. Units are painted in various liveries including Network SouthEast (NSE), Railtrack's brown livery, Railtrack's blue/green livery, and Network Rail's new all-over yellow livery. In addition, two units have been specially repainted in old BR liveries, namely maroon and blue/grey.

The current fleet is listed below:

[edit] Silverlink

Silverlink inherited a small fleet of four "Bubble Cars". They were mainly used on the Marston Vale Line from Bletchley to Bedford, as well as non-electrified lines in North London, such as Gospel Oak to Barking. The units replaced the previous fleet of Class 108 and Class 115 units, and were supplemented with a fleet of Class 117 units cascaded from Thames Valley services.

The four units, nos. 55023/27/29/31, were based at Bletchley depot, where staff repainted set L123 (55023) into its original British Railways green livery. The others remained in obsolete Network SouthEast livery. In 1996, set L123 was withdrawn from traffic, and the other three were hired to Great Eastern for use on the Sudbury branch to Sudbury . These returned to Bletchley in 1997/98. Two of the units (121027/029) were repainted into Silverlink's purple and green livery, and the third (121031) was repainted into Network SouthEast livery. The three units also received names from withdrawn Class 117 units.

• 121027 - Bletchley TMD
• 121029 - Marston Vale
• 121031 - Leslie Crabbe

The units were replaced on Silverlink duties in 2001 by Class 150 "Sprinter" units cascaded from Central Trains. The units have all since been transferred to departmental duties.

[edit] Preservation

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