This was a great game when released, but now it's showing its age. It's satisfyingly challenging, especially on the higher difficulty settings.
It's fun laying out your railway and you get a good sense of getting better at the game the more you play it, as you get involved with the more advanced functions, such as personal wealth and the stock market. The differing goals on each level, the changing emphasis depending on the year and the big shift between difficulty levels are easily enough to hold your interest over the long-term. While there's some luck involved, particularly with the economy, success is mostly a case of skill and planning. The economic model is good enough, if not spectacular.
On the downside, the user interface looks and feels like it was designed in 1998 (as it was). It can be hard finding some of the more important functions (or even the existence of them in some cases). I would recommend at least scanning through the manual.
The graphics are perfectly functional - as an isometric rather than a 3D game, they've aged better than most of this vintage. The intra-level cutscenes set the scene for the level quite well. I enjoyed the bluegrass music, even though I'm not a fan of the genre - it fits the pace of the game exactly.
As in common with many games in this genre, there's a "tipping point" at each level where you're sure that you'll be successful. The game has ten speed levels and this comes in very handy at that point.
If you're having trouble deciding, "Railroad Tycoon 3" is definitely the better game, particularly the economic model and user interface. However this can be difficult to get running on modern systems. "Railroads!" is almost a different kind of game, much easier and less in-depth - I didn't like it.
If you like management sims, you should get a lot of enjoyment out of this, particularly as it's so cheap. If you're not sure, or haven't played that style of game much, you'll probably be better off buying something more modern.