Controlling the main lines

The main issue on my mind at the moment is which companies should be able to run on the main lines through the north of England to Scotland - the East Coast Main Line (ECML) and West Coast Main Line (WCML). I originally had a couple of key cities that controlled each route - York and Newcastle on the ECML and Carlisle and Preston on the WCML. Each city could upgrade to a tile with two station markers. This meant that companies would have to co-operate to run the London to Scotland routes. On the West, the LNWR, LYR and Caledonian would be likely allies, while on the East the alliance might comprise the NBR, NER and GNR.

A couple of changes I have in mind would threaten this balance. On one hand, the population of Carlisle, Preston and even York was only high enough to qualify them as towns compared to other cities on the map. On the other hand, I would like to keep 1-station cities to have just one marker space: partly to reduce the number of markers needed in the game and partly to make cities such as Stoke and Leicester less central.

If I change Carlisle, Preston and York to towns, then access to the main lines would be much easier; almost any company could run along one or the other. This would mean that I wouldn't need rules for alliances. But the result seems too liberal, with no competition for access to these important routes.

If I reduce the number of markers these cities can hold. then whichever company controls them will be in a central position for any alliance. This could give too much control to the LYR and GNR, with no competition for alternatives.

An alternative would be to make some of them grey hexes, with a fixed low income and a sufficient number of marker spaces, or to have two types of 1-station cities. I'm less keen on the latter approach because I already have three different types of city, in addition to towns and plain hexes.

There is a related issue that I may need to adjust the map to ensure that Preston and York really do control the main lines, with no easy bypasses. This is similar to the recent changes I made to ensure that Carlisle and Newcastle control the passes further north.