[1] However, this came at the cost of either discarding the Kylchap exhaust or the self-cleaning device in the smokebox, of which the former was omitted by the design team.

A new smoke deflector design was fitted, although the omission of the Kylchap exhaust led to visibility issues during service.

525 A.H.Peppercorn, was outshopped from Doncaster in December 1947 on the eve of nationalisation, and named after the designer of the class, Arthur Peppercorn.

The first two of the class were turned out in LNER apple green livery, and this colour was also applied to the next 13 engines delivered between January and August 1948.

60539 Bronzino emerged in August 1948 with Kylchap double blastpipe and chimney in place of the self-cleaning apparatus as an experiment, with Nos.

[5][6] The class's 50 sq ft grate, a remnant of the P2 lineage (from both Thompson and Peppercorn) boilers, meant the A2's were capable of high power and endurance; however, with the exception of the Aberdeen road, there was little need for this large grate firebox in the postwar era, and as a result, on comparable duties the A2's were heavier on fuel than the Gresley machines which pre-dated them, but for outright power and haulage capability, they were the logical successor to the P2 class, and finally provided the answer the Edinburgh-Aberdeen route required.

Initially, the A2s were based at depots the length of the East Coast Main Line, ranging from New England (Peterborough) in the south to Edinburgh's Haymarket.

[6] In 1949, five were put to work on the Edinburgh-Dundee-Aberdeen route and proved the ideal engines for its stiff gradients and sharp curvature.

60527 Sun Chariot started from Aberdeen with a 400-ton train and reached Montrose, Arbroath and Dundee ahead of schedule.