The London and North Eastern Railway Class K5 consisted of a single rebuild of LNER Class K3 2-6-0 No. 206 (later No. 61863), rebuilt in 1945 by Edward Thompson. The rebuilt locomotive had a new boiler and two, instead of three, cylinders following earlier rebuilds of other Gresley designs. The aim of the rebuilds was to move away from the well established three cylinder policy achieving similar results through higher boiler pressure and two larger cylinders. Easier maintenance and greater availability was the objective. This locomotive was withdrawn in 1960, and later scrapped.

• Ian Allan ABC of British Railways Locomotives, part 4 (1948 ed.). p. 17.^{[full citation needed]}

• The Gresley K3 and Thompson K5 2-6-0 Moguls LNER Encyclopedia