British Rail Derby Lightweight
The British Rail Derby Lightweight diesel multiple units, were the first such trains to be built en-masse for British Railways. The units were built at BR's Derby Works from 1954 to 1955. The units were built in various formations, including 12 power-twin 2-car units, 84 power-trailer 2-car units, and four 4-car units. The two single car units were originally built as a two-car unit and then split two years later when demand came about.
| British Rail Derby Lightweight | |
|---|---|
Derby Lightweight power car no. 79018 at Bewdley on the Severn Valley Railway | |
The refurbished seating in the 2nd class saloons of the Trailer Car 79612 - 2021 | |
| In service | 1954-1969 |
| Manufacturer | BR Derby Works |
| Replaced | Steam locomotives and carriages |
| Constructed | 1954-1959 |
| Number built | 217 vehicles |
| Number preserved | 2 sets |
| Formation | 1, 2 & 4 car formations |
| Capacity | 16 1st + 53 3rd class (motor composite), 61 3rd class (motor third brake) |
| Operators | British Rail |
| Specifications | |
| Car length | 57 ft 6 in (17.53 m) |
| Doors | 2 on each side |
| Maximum speed | 62 mph (100 km/h) |
| Weight | 27 tonnes (26.6 long tons; 29.8 short tons) power car |
| Prime mover(s) | Two BUT |
| Power output | (AEC) 125 bhp (93 kW) except BUT (AEC) 150 bhp (110 kW) for single units |
| Multiple working | ◆ Yellow Diamond |
| Track gauge | 1,435 mm (4 ft 8+1⁄2 in) standard gauge |
Body framing was extruded and riveted together. Panelling was welded into continuous sheets and riveted to the frame. Luggage racks were light alloy. The floors had 2 layers of flameproof hardboard, covered with linoleum. To reduce noise and condensation, the inside structure and undersides were sprayed with asbestos. Lighting was by 60-watt, 24-volt lamps charged by belt driven dynamos. Heating was oil fired. Standard mild steel bogies ran on Timken roller bearings.
Contemporaneous with these units was the unique Battery Electric Multiple Unit.