|Number built:||354 (182 2 and 3 car sets)|
|Engine:||Cummins NTA855R1/3 or Perkins 2006-TWH diesel engine per power car|
|Power:||350 hp (260 kW) or 400 hp (300kW) per vehicle|
|Formation:||2-car : Driving Motor Standard Lavatory (DMSL)+DMSL
or DMSL+Driving Motor Composite Lavatory (DMCL)
3-car : DMSL+Motor Standard (MS)+DMSL
The Class 158 operates as either a 2 or 3-car set, mostly with a Cummins engine though a few were fitted with Perkins engines instead. Currently the fleet is split into the 158/0 and 158/9 sub-classes. The latter were originally 2-car sets but were beefed up into 3-car by the addition of an extra driving coach though the cab of this is locked out of use.
The Class 158 is in operation with Northern, Scot Rail, Arriva Trains Wales, South Western Railway (formerly South West Trains), Great Western Railway and East Midland Trains. Twelve 3-car sets were also built by BREL Derby for the Thailand state railway and also continue in service.
|Arriva Trains Wales 158 836 at Aberystwyth|
|South West Trains 158 889 passes Leamington Spa|
|GWR 158 953 at Portsmouth Harbour|
|East Midland Trains 158 777 at Derby|
|Northern 158 752 at York|
|EMT 158 854 approaches Duffield|
 Colin J Marsden, DMU and EMU Recognition Guide (Ian Allan, 2013) p. 140