LNER Class A4 2509 Silver Link was a 4-6-2 "Pacific" built in 1935 for the London and North Eastern Railway. It was the first of the Streamlined Class A4s built to haul express passenger trains on the East Coast Main Line (ECML). 2509 was one of four A4s to be painted in a special silver livery to pull a new train called the Silver Jubilee.

The LNER 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 record as the world's 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; they themselves proving to be worthy successors to the A4s. 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.