British Rail Class 769

The British Rail Class 769 Flex is a class of four-car 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 319electric multiple unit (EMU), a conventional unit type which had become surplus to requirements during the 2010s.

The conversion process was carried out by a partnership between the rolling stock leasing company Porterbrook and train manufacturer Brush Traction. The conversion principally involved the addition of a pair of MANdiesel 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 Sprinterdiesel multiple unit (DMU), and the switchover between EMU and DMU modes can be carried out while the train is in motion. A parcels variant has also been produced, the Class 768.