Mainline steam trains in Great Britain
The most famous steam locomotive operating on the British main line is the 1923 built "Flying Scotsman". After being taken into public ownership in 2004, following a decade long refit it returned to mainline service in 2016. The fastest steam locomotive ever built, the 1938 built "Mallard", was also certified for main line operation briefly in the 1980s.
2-8-0+0-8-2
The London and North Eastern Railway (LNER) owned a single Class U1 Garratt, built by Beyer, Peacock in 1925. It was designed by Nigel Gresley for banking coal trains over the Worsborough Bank, a steeply graded line in South Yorkshire and part of the Woodhead Route. The Class U1 was both the longest and the most powerful steam locomotive ever to run in the United Kingdom.