British Rail Class 901

The Class 901 designation is used for two former British Rail Class 101 diesel multiple units converted for departmental use. They were reclassified from the Class 960 series in early 2004 by their owner Network Rail.

The two units are described below.

901001

This unit was converted in 1986 from a Class 101 power-twin unit. It was rebuilt as an Ultrasonic Test Train, replacing the former-Derby Lightweight unit that was previously used for this task. The unit was substantially rebuilt, including new headlight clusters, sealing of many windows, and later fitting of video and floodlight equipment for night-time use.

The unit also incorporates a heavily-modified former Class 432 4Rep driving motor vehicle, which is now an intermediate trailer.

The Units Class 101 Power Cars are unique, as they are the only first generation DMU cars to have been converted to Air Brakes (both Westinghouse and Electro-Pnumatic). Most of the brake equipment came from former Class 50 Diesel Electric Locomotives, with some parts from ex-Southern Region EMU stock. All first generation DMU's were fitted with Vacuum Brakes from new.

The unit was originally painted in a unique silver and grey livery. This was replaced by Serco red/grey in the mid-1990s, followed by Railtrack Blue/lime green and finally Network Rail's all-over yellow.

901002

This unit was converted in 1991, also from a power twin unit. It was rebuilt by the Research & Development Division (R&DD) of British Rail as a test train known as "Lab 19 - Iris II", supplementing the original "Test Coach Iris", which was a former-Derby Lightweight single-car unit.It was used initially for radio survey work particularly with the National Radio Network (NRN) and later for video survey work including extensive signal sighting on the WCML prior to the introduction of 125 mile/h running.

Like 901001, this unit has carried various liveries, starting with BR Research's silver and grey livery, similar to that carried by 901001. This was followed by Serco red/grey, Railtrack Blue/lime green, and most recently the latest Network Rail all-over yellow livery. This unit was withdrawn and stored at Derby's Railway Technical Centre and was sold by Network Rail to a private buyer in early 2008. It is now resident at Dunster on the West Somerset Railway where it is being re-painted into BR green and will be used on Pway trains.