Hornby TT3021M BR, Class 43 HST Train Pack - Era 7

British Rail introduced the InterCity 125 High-Speed Trains in 1976. They were considered the fastest diesel trains in the world. They operated at speeds of 125mph on the Great Western Main Line and the East Coast Main Line before being introduced to other lines as their use spread.

When originally built at Crewe Works by BREL, these trains consisted of a pair of Class 43 power units and a rake of Mk3 coaches. They were considered to be diesel multiple units and allocated as Class 253 to the Western Region and Class 254 to the Eastern Region, as it was envisaged that the sets would remain in fixed formation.

However, with the increasing electrification of the UK railway system, the use of Class 43s has reduced, and their services are no longer required on the East Coast Mainline. The introduction of the Class 800 sets has also relegated the Class 43 to regional services, with Scotrail and GWR being the two largest operators of the Class in 2022. 

Despite this, many Class 43s have been preserved due to their status as the fastest diesel trains in the world. The Class 43s would begin to see a reduction in their use as electrification became more widespread around the UK, with their services no longer being required on the East Coast Mainline. With the introduction of the Class 800 sets, Class 43 has been relegated to regional services, with Scotrail and GWR being the two largest operators of the Class in 2022. Due to the locomotive's status as the fastest diesels in the world, many examples have been preserved.