Indeed - a fascinating video. Thank you.
Going off the thread slightly, it did make me wonder what might have happened to the fortunes of the railways had there been no WW2, and, presumably, no need for Nationalisation in 1948?
Would the "Big Four" at the 1923 Grouping have continued as the basis of a privatised railway up to the present day?
I do realise this is probably a question worthy of a discussion thread of its own.