I think that starting with warmed train, or better a hot engine coolant system would help considerably. When the engine is working hard almost unlimited heat should be available from the coolant. It is idling prior to departure that produces little heat.
Any electric cooling fan should be automatically disabled until the coolant is hot.
Yes, I don’t doubt the science behind that, but just the reality - which is that a lot of units built around that time had a poor heating systems installed and poor insulation. It matters not how hard an engine is working if the system of pipes, radiators, thermostats etc that feeds into the saloons isn’t very good.
As the article says, these trains didn’t heat up the whole day, when the engines would have been powering for a considerable percentage, and that tallies with my experience on the system originally fitted to the Turbos, in less extreme temperatures.
Contrast that with a modern unit like the
IET▸ which I’ve watched heat from 5 degrees to 18+ degrees in less than half an hour of idling from being left switched off overnight.