Copy of RAS- 926

Cock o’ the North stands at Kings Cross during trials – Rail Archive Stephenson

No. 2001 Cock o’ the North entered traffic in May 1934 and was tested on various routes in England and Scotland, in consequence small adjustments were made to the exhaust cams in the poppet valve gear and an oil circulation system was incorporated for the camboxes. In December of that year the locomotive was sent to the new test plant at Vitry-sur-Seine for evaluation, a video of which can be seen here. While in France the loco also hauled test trains with a dynamometer car in the consist and produced some impressive runs, recording in excess of 2,000dbhp. The trials did throw up some problems with the design, mainly concerned with the bearings and ash-pan dimensions.While in France the optimum dimensions for the blast arrangement were finalised and Kylchap assembly set. You can see rare Pathe News footage of Cock o’ the North at Vitry here.


No. 2001 is seen on the rollers at the Vitry test plant – Gresley Society Collection

Back in Britain No. 2001 was put to work in Scotland, followed shortly by the other members of the class. The ACFI feed water heater fitted to No. 2001 proved troublesome, requiring, as it did, exhaust steam to pre-heat the injector supply which required the locomotive to run with the regulator constantly open, something that was not possible on the Aberdeen route. The locos did prodigious work hauling 550 ton trains on the Aberdeen route but No. 2001 had an appetite for coal. As their careers progressed other faults became apparent, they showed a tendency to run hot axle bearings and develop excessive wear in the motion.


During road tests in Britain, No. 2001 is seen with an instrument shelter – Gresley Society

As noted before, Cock o’ the North and Earl Marischal were both equipped with the A4 front end and when No. 2001 was at Doncaster in 1937 for this work the opportunity was taken to fit the loco with Walschaerts valve gear as well as removing the feed water heater. If the class had a common Achilles heel it was the leading pony truck which proved poor at “steering” the leading driving wheels and set up frame stresses which led to big-ends running hot and crank axle trouble. Gresley had given the locos a leading truck similar to type fitted to his K3 moguls, a design which was perpetuated in the V2 class (although these were successfully modified to resolve the issue).

As a small class which required higher than average attention it inevitably came under close scrutiny from Edward Thompson, the L.N.E.R.’s new C.M.E. following Sir Nigel Gresley’s premature death. The issues with the leading truck may well have contributed to his decision to rebuild all six P2s as A2/2 Pacifics during 1944. Thus the magnificent Mikados effectively became extinct, the final blow falling when the rebuilt engines were scrapped in 1961.

Copy of RAS- 928

Cock o’ the North in full flight – imagine this in the 21st century! – Rail Archive Stephenson