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.
Metropolitan Railway electric locomotives
The second ten, also constructed by Metropolitan Amalgamated, were built to a box car design with British Thompson Houston control equipment. These locomotives weighed 47 tons, and were long over buffers and entered service in 1907. The control equipment was replaced with the Westinghouse type in 1919.
In the early 1920s, the Metropolitan placed an order with Metropolitan-Vickers of Barrow-in-Furness for rebuilding the twenty electric locomotives. When work started on the first locomotive, it was found to be impractical and uneconomical and the order was changed to building completely new locomotives using some equipment recovered from the originals. The new locomotives were built in 1922-1923 and weighing 61½ tons, they had four motors, giving a one-hour rating of and a top speed of .