Question to the Department for Transport:

To ask the Secretary of State for Transport, how many new diesel four car units have been introduced to the rail network in each year since 2015.

Between 2015 and 2022, 389 units were ordered that are fitted with diesel engines, 66 of those units comprise of four passenger vehicles with the remainder of the units ordered comprising of two, three, five and nine passenger vehicles. Greater Anglia introduced 24 Class 755/4 units with four passenger vehicles into service in 2019, the remaining 42 units for West Midlands Trains and Transport for Wales are currently in build or on test.

Of the 389 self-powered units ordered between 2015 and 2022, 175 were diesel only, and 214 are bi/tri-mode units and are trains that have the ability to operate from diesel, overhead line or battery power as appropriate.