Ahh thanks for asking! I've just recently started playing the game starting in 1850 on the slowest date speed but it really does seem like a perfect game for autists (cause trains). My experience only goes to 1866, so do take that in fact.

My only reference point is Cities Skylines and obviously speaking the transportation aspect of the TPF2 is way more in-depth than C:S. Currently I'm easily managing the traffic issues, although truck stations can be sometimes a traffic bottleneck. Figuring out train routes, putting down signals, passing lines can be a good brain game for me which gives me a lot of satisfaction if I succeed at it. In terms of difficulty, I'm playing on medium without industry frequencies and the game just "snowballs" in difficulty. So if you prop down 1 or 2 profitable lines then your life already starts to get noticeably easier over time.