See what you mean, GSR. The 800 class "mid green with bluish tint", complete with its yellow and black lining, would probably have spread instead of the all-over unlined grey. It would also have adorned a fleet of newer-built standard classes of steam engines. Possibly, main line diesels might have been experimented with, as the LMS in England did.
The narrow gauge lines then deemed worth saving (T & D, WCR, and C & L) would have been comprehensively modernised, and in the case of the WCR and T & D, we know that at least vague consideration had been given to conversion to 5ft 3.