>Just imagine what might have been had Sir Nigel Gresley worked for GWR!
Their engines would have become more efficient
Gresley was not afraid to learn lessons from anyone. Having previously had inconclusive evidence of the benefits of long travel valves, a trial between a GWR (castle I think) and of his early pacifics in the 20's led to a rethink. This led to the A3s, A4s and finally V2s.