The J72 Class of tank engine possess the unique record of having been constructed at varying periods over a span of 54 years under three railway company ownerships: NER, LNER & BR.
Designed by T.W. Worsdell, and originally designated Class E1 by him, the J72 was introduced in 1898 for light goods and shunting duties. They were a further development of the near-identical J71 Class, which has slightly larger diameter wheels, and were built at Darlington, Doncaster and by the Armstrong-Whitworth Company.
Eighty-five J72's were built, the last LNER ones in 1925, then, after nationalisation, between 1949-51, British Railways built a further batch of twenty-eight identical to the original 1898 design making a class total of 113.
During the late 40's, a number of J72's were fitted with vacuum braking, enabling them to work as passenger pilots and on carriage shunting duties.