The J72 Class of tank engine posses the unique record of having been constructed at varying periods over a span of 54 years under three railways company ownerships: NER, LNER, & BR. Designed by T.W. Worsdell, and originally designated Class E1 by him, the J72 wa introduced in 1898 for light goods and shunting duties. They were a further development of the near-identical J71 Class, which had slightly larger diameter wheels, and were built at Darlington, Doncaster and by the Armstrong-Whithworth 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, anumber of J72's were fitted with vacuum braking, enabling them to work as passenger pilots and on carriage shunting duties.