Wheeltapper, aka Mike Dews, has just created a video based on activity at the North end of York Station in 1955: https://sites.google.com/site/cambridgelinesrailworks/home or direct on Youtube:
Had a pound down there behind an A4 on the Down Elizabethan the other day, non-stop to beyond York but the scenario split into four parts (with rolling starts) due to AI traffic's memory limitations. It is a great route, Neil, I have no idea how you found the time to put it together. John