Arthur Peppercorn

Thompson was already 60 years old, and both he and the LNER recognised that his appointment was not a permanent solution: both Peppercorn and Harrison were ready in the wings.

[2] Edward Thompson had set down strict guidelines for the incoming CME, relating directly to the upcoming design of an Express Passenger Pacific.

The belief was that the problems were caused by a lack of frame support at the front end, largely due to the cylinders not being aligned with each other (an aspect of divided drive combined with equal length connecting rods).

Previous Gresley Pacifics on the LNER had a 41.25 sq ft grate, which had proved sufficient for any tasks not needing very high power output.

At the time these classes were built however, the trainloads of WW2 were massive in comparison to those for which the Gresley Pacifics had been designed and built, and both Peppercorn and Thompson had to design engines which could meet that requirement: heavier fuel consumption on lighter duties was a compromise which was needed in order to meet the higher demands of the day.

Despite the fuel consumption concerns, in addressing the limitations of both the Thompson Pacifics and those of Gresley, Peppercorn had produced engines which could master virtually all the work put to them without the drawbacks of centre big-end bearing overheat, leaking steam pipe connections, frame fractures or any of the other flaws which blighted the previous LNER Pacifics.

After post-war frame alignment and fitting of double Kylchap Chimneys, the A4s became once more the standard-bearer of the East Coast Main Line.

By carefully incorporating the best of Gresley and Thompson design, as well as ideas of his own, Peppercorn had produced two masterpieces of durability and low service cost.

The A2s were particularly powerful, and finally produced the answer to the heavy services on the Edinburgh to Aberdeen Line which had blighted both Gresley (P2 Class- too long a rigid wheelbase) and Thompson (A2/2 and A2/3- both lacking adhesion).

Arthur Peppercorn's widow, Dorothy Mather, was honorary president of the A1 Steam Locomotive Trust, builder of Tornado, from the early 1990s until her death in 2015.