The Flying Scotsman titled train crosses Barnby Moor in the charge of LNER Gresley A4 pacific no. 4485 Kestrel. This shot is dated 1937 which suggests that the livery is green but I can see no sign of the associated lining and I suspect that this was taken after 12/37 when 4485 was repainted in garter blue livery.
Kestrel would be renumbered 26 in the 1946 LNER scheme and be renamed as Miles Beevor in November 1947. As BR no. 60026 it was one of the A4's that were given a stay of execution in England in the early 1960's and moved north of the border to St. Margaret's shed in October 1963 followed by its final allocation to Aberdeeen (Ferryhill) in April 1964. Withdrawal came in December 1965 but there was still more to come as the driving wheels were transferred at Crewe Works to no. 60007. Removal of the loco for scrapping by Hughes Bolckows didn't occur until September 1967.