The one we have been going with for first play is 1846: Race for the Midwest, and that’s proven successful. It’s got a little bit of extra complexity, but it is very very forgiving. It also has a more straightforward directional heuristic of wanting to own a company and run it well. Also, the creator of this game is Thomas Lehmann, the creator of Race for the Galaxy, and many other greats. Whether you want to race to space or Chicago, he’s got you covered.
Here’s the rules pdf
Alternative game is 1889. It is the simplest game in terms of rules. However, it is more like other train games in that it is brutal and cutthroat. How to win is less straightforward. It’s easy for an inexperienced player to go bankrupt, and that will cause the entire game to end immediately.
In general, the hard part about these games isn’t the rules themselves. They aren’t really any harder than any other somewhat serious board game. What’s hard is the graphic design of the games is not good for new players, though the web site does its best to improve upon that. And most of all, knowing how to actually play well at these games is hard. Not hard like Go, where you’ll lose 1000 games before you win one. Hard in that the path to victory does not align with natural inclinations.