Just out of interest, here's what happens if you don't do your gauging checks:
This is at Derby North End Dock, my class 56 loco is not quite touching the brickwork. However, if it wasn't a 5 mph dead end line and I'd gone through at 60 mph, the movement of the loco body on the suspension would almost certainly have created some brick dust and, er, reprofiling of the platform edge.
No excuse for NR not thinking far enough ahead to do the gauging checks in good time.
Not being a railway lover nor too knowledgeable on the subject but I was brought up thinking all trains in Britain were built to the same width and height so they would all go under railway bridges and fit alongside platforms and all other railway gubbins without hitting anything so is the Flying Scotsman any different.