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.
Mallet locomotive
Mallet designs were popular in Hungary, too. 30 of (B'B) were built between 1898–1902 (the last one served until 1958). was a (1B)B locomotive in service between 1905–1969 and (C'C) until 1962. The strongest Mallet-locomotive of the Hungarian State Railways was MÁV 601, a (1'C)C type steam locomotive. With 2200 kW power, MÁV 601 was the most powerful steam locomotive built before and during the First World War in Europe.