Types of city, types of train

For a while now, I've had several ideas for types of train in the end game. What I hadn't realised before was the crucial effect of design decisions about trains in the early game. I need to decide whether a simple '2' train can stop at dot towns (as in most 18xx games), can skip dot towns (as in 1861) or even take income from all dot towns on its route. And this affects the map: which towns appear as dot towns and which need to be large towns so that companies can start in them?

In the UK, companies quickly ran long routes. E.g. the LNWR started by running London to Manchester via Birmingham, while the GWR ran London to Bristol via Reading. To replicate this and give some feel for authenticity, a company with '2' trains has to start somewhere in the middle of these routes. In 1829 and 1825, Francis Tresham handled this by drawing hexes such as Wolverton, Swindon and Doncaster with fixed track and permanently low income. The starting companies run can '2' trains from these to connect up the longer route. When the '2' trains are replaced, a larger train can run the whole route on its own.

I want to avoid fixing the track in such hexes, so that players have more options for play. But neither do I want towns such as these to compete with the larger cities as sources of income. So I'm thinking of introducing a class of city that can accept markers and be promoted to increase route options but which has permanently low income. (Actually. I might give them a choice of either adding more routes or growing in income, but that will depend on what works in practice).

The UK is also densely populated. Almost every hex should contain at least a dot town. This ubiquity makes me wonder whether it's worth having the dot towns in the game at all. I certainly don't want the annoyance of a "double-heading" rule to get past the dot towns in the early game. I could just allow trains to skip dot towns, but this makes them almost pointless (apart from controlling how the track may develop).

I have the notion of allowing T trains to run as suburban trains in the late game, alongside E trains running on the same track. (This idea is inspired by an 1825 variant by Lou Jerkich). The suburban trains would only count income from dot towns, while the express trains would have to skip them. But perhaps it would be simpler to remove the dot towns completely and just give the suburban trains an income per hex on their route?