British Rail Class 769
The British Rail Class 769 Flex is a class of bi-mode multiple unit (BMU) converted by Brush Traction, and running in service with Northern Trains. The train is a conversion of the existing Class 319 electric multiple unit (EMU), a conventional unit type which had become surplus to requirements during the 2010s.
| British Rail Class 769 Flex | |
|---|---|
Northern Trains Class 769 at Manchester Piccadilly in 2021. | |
Interior of a Transport for Wales unit | |
| In service | November 2020 – present |
| Manufacturer |
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| Built at |
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| Family name | BR Second Generation (Mark 3) |
| Replaced | |
| Constructed |
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| Number in service | 8 |
| Number scrapped | 1 vehicle |
| Owners | Porterbrook |
| Operators |
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| Depots | |
| Specifications | |
| Car body construction | Steel |
| Car length |
|
| Width | 2.82 m (9 ft 3 in) |
| Height | 3.58 m (11 ft 9 in) |
| Doors | Double-leaf sliding pocket, each 1.010 m (3 ft 3.8 in) wide (2 per side per car) |
| Wheelbase | Over bogie centres: 14.170 m (46 ft 5.9 in) |
| Maximum speed | 100 mph (161 km/h) |
| Prime mover(s) | 2 × MAN D2876 (one per DT vehicle) |
| Engine type | Inline-6 4-stroke turbo-diesel with SCR |
| Displacement | 12.8 L (780 cu in) |
| Traction motors | 4 × GEC G315BZ |
| Power output | 390 kW (520 hp) per engine |
| Electric system(s) |
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| Current collector(s) |
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| UIC classification | 2′2′+Bo′Bo′+2′2′+2′2′ |
| Bogies |
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| Minimum turning radius | 70.4 m (231 ft 0 in) |
| Braking system(s) | Electro-pneumatic (disc) |
| Safety system(s) |
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| Coupling system | Tightlock |
| Multiple working | Within class |
| Track gauge | 1,435 mm (4 ft 8+1⁄2 in) standard gauge |
The conversion process is carried out by a partnership between the rolling stock leasing company Porterbrook and train manufacturer Brush Traction. The conversion principally involves the addition of a pair of MAN diesel engines (one under each driving trailer vehicle), the output of which is fed into ABB-provided alternators to power the existing electric traction systems. According to Porterbrook, the Class 769's performance under diesel power is either equal or superior to that of a Class 150 Sprinter diesel multiple unit (DMU), and the switchover between EMU and DMU modes can be carried out while the train is in motion.