LNER Class A4
The Class A4 is a class of streamlined 4-6-2 steam locomotive designed by Nigel Gresley for the London and North Eastern Railway in 1935. Their streamlined design gave them high-speed capability as well as making them instantly recognisable, and one of the class, 4468 "Mallard", holds the world record as the fastest steam locomotive. Thirty-five of the class were built to haul express passenger trains on the East Coast Main Line route from London Kings Cross via York to Newcastle, and later via Newcastle to Edinburgh, Scotland. They remained in service on the East Coast Main Line until the early 1960s when they were replaced by Deltic diesel locomotives. Several A4s saw out their remaining days until 1966 in Scotland, particularly on the Aberdeen - Glasgow express trains, for which they were used to improve the timing from 3.5 to 3 hours.
VR Class Dr12
When it was introduced, the Dr12 gave drivers a new experience of comfort and forward visibility compared to steam locomotives, but compared to the newer VR Class Dr13, the Dr12 had a heavy axle load and slow acceleration with a top speed of only 120 km/h. The reason for this was that the locomotive turned out to be underpowered. The problem of the top speed was corrected in the last 10 locomotives by changing the transmission in such a way that the technical top speed was increased to 140 km/h, but this feature was never used. As a result, the entire locomotive series had a maximum permissible speed restricted to 120 km/h. However, due to the high axle weight, the Dr12 had good adhesion properties and it was considered to be a reliable and robust locomotive. It was well-suited to heavy trains with relatively low speed requirements.