So as not to be vague, and since I just pushed a version I'm starting to be vaguely happy with...

https://tylereaves.github.io/uk-rail-map/

This is the result of probably a few hundred round trips. The really interesting part of the problem is keeping it both relatively true to real geometry, while greatly exaggerating it horizontally so you can actually see the individual running lines/sidings, like a signaling schematic.