Perhaps I’m going mad based off the praise heaped in other responses, but - something seems wildly off with the locations?

I just witnessed a London Liverpool street service plough through the M25 motorway - about 40 miles south of it's typical route and 5 miles south of the nearest actual railway. Dozens of the trains seem to be traversing through the English channel/La Manche towards the north sea.

In fact the number of trains actually tracking a rail line (and this is outside of the cities where the tube/metro might obscure this) seems in the minority. Most seem to be going straight through the middle of farmers fields on some obscure course unrelated to theirs.