Query to people who have played this game a lot more than I have:
What would the downsides be for allowing trains to run through the small cities without counting against the engine ala 18AL/18GA? Or perhaps allowing trains to skip them if they so desire ala the whistle stops in 1860?
It would reduce the value of the diesel trains too much in comparison to the others.
I find the small cities are an oddity in 1830 because players seem to rationally want to avoid them. Does this serve a useful game purpose that I didn't notice in my first game, or is it just a quirk that can be discarded with little loss?
As said above they (can) make the diesels worth their price.