I love computational mapping projects, because there is this hard problem of which towns to show on the map.

Your Scotland map shows towns without rail (although some had rail previously, like Callander, Aberfeldy), it prefers insignificant (population-wise) places while ignoring the larger cities next to it (Scone instead of Perth, Bannockburn instead of Stirling, Inverness is missing, Dundee is missing, Aberdeen is missing). All these places are drawn on the map, but not labelled.

All this clearly shows to me how bad it is. Yes it makes it look pretty, but given your task, I would have expected to give you meaningful map labelling.

Something basic like this would get you a long way:

    0. cluster population centers into commonly known cities (i.e. show London instead of Islington or Walhamstrow)
    1. display names of the top 10 population centers in the UK
    2. display towns with stations (if crowded prioritize termination points and junctions, and prioritize larger places over smaller places)

Having said that, its pretty cool to see the new and old network when zoomed in (assuming that it is half-way correct)