The Caledonian Railway 49 and 903 class 4-6-0s
I was very interested to read David Anderson’s account of J F McIntosh’s splendid 6ft 6in 4-6-0s – Steam Days, February 2025. Very brief contemporary footage of a McIntosh Dunalstair IV 4-4-0 in action and its prime exists, oh that a similar record was not also made of one of these engines in full cry!
I think the rather longer (30 cf 23 year) life of the first two engines is quite readily explained. Not only were new cylinders, re-designed in November 1923, fitted in early LMS days, but also around this period, new frames, that had been re-designed in April 1920. Furthermore, a third boiler, containing somewhat shorter and fewer, but larger diameter firetubes, had also quickly been built as a…