Colwick’s allocation of Ivatt 4MTs averaged around fifteen during 1963/64, but all had gone by the start of 1965. No.43155 was one of the last few built, at Doncaster in December 1951, and spent its early years at Melton Constable on the Midland & Great Northern before moving to Boston for just two weeks when that line closed and then on to Colwick.