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.
Russian locomotive class Ye
In 1944 the first steam engines of the Е series, which was given index "a" (U.S.), resulting in the designation of Еа. The numbers of locomotives built by ALCO began at #2001 and the Baldwin built locomotives at #2201. In September the same year, the first Baldwin built locomotive (Еа-2201) was sent to the pilot ring VNIIZhT which was tested until October. In the course of the tests, it was found that forcing the boiler to , a cutoff of 60% and at a speed of , the engine could develop of tractive effort. It was also found that the locomotive could achieve , which was a 20–25% increase compared to the World War I engines (). The improved performance was achieved through improved boiler and the use of mechanical stoker. The temperature of superheated steam was typically 572–644 °F (300–340 °C), and no more than 698 °F (370 °C).