It's trickier than you think! Even for the modern era, the railroad tycoon games are surprisingly deep and sophisticated economic simulations. I still haven't found one to equal Railroad Tycoon 3, which has this kind of neat reactive diffusion field pricing engine.

The modern equivalents (I'm thinking of Transport Fever 2) while they are fun games just lacks the ability to build and manipulate a real economy by doing things like e.g. putting an industry in a town and then transporting goods there to satisfy the industry, making both your train line and the industry wildly profitable.

I really admired Transport Tycoon which had those 3 additionals transport channels. Have you tried it? I love the shuttle buses which you can use to connect to an external (to the city) airport, railroad track that can go throughout the whole map, and the ships that transport mostly oil for fun and profit...

There's also a whole, albeit niche, board game genera of so called 18xx game (eg. 1889 Shikoku) that deal with the economic aspects of 19th century railroads.

Usually dry as sand, but some of the heaviest games out there in terms of complexity.