Railway Empire is a bit more "board gamey" than simulation.
The basic gameplay mechanics are
* all towns start at a base size (level 1 is any population, level 2 is 40k, level 3 is 60k, maybe not exact numbers but you get the idea.) all towns have one factory slot already filled, but level 2, 3, and 4 unlock additional building slots, two of which are factories and one of which are special buildings with various modifiers.
* to grow, towns need to have their needs satisfied. the list of goods generally varies by region for flavor purposes but there are raw goods (e.g. wheat) and factory goods (e.g. beer); the former come from points of interest around the map and the latter come from factories in previously mentioned factory slots. Once supply of all goods is above a threshold the population of a town will increase, otherwise it will decrease.
* if you want to be a truly vertical conglomerate, you can buy the businesses and factories yourself and do all the micro; the latter can also be constructed by you if there is a free slot, but it's not necessary as the town can do it (though they don't necessarily make good choices, and buying after the fact is expensive, particularly if it becomes profitable). businesses also have production levels to scale up, which comes in handy since bigger cities will need more goods, and factories usually demand quite a lot of a raw good.
* passengers and mail exist. all city pairs have some mail and passenger demand between them, and the travel demand is usually a function of origin city size and distance. if your train meets the criteria to be an "express" train, revenues from those goods will be exceeded. the risk there is that if your train is not passenger only, freight may slow it down enough to not qualify for express standard. and you research locomotives throughout the years, so if a competitor develops a much faster locomotive than yours all your expresses are in danger unless you catch up!
* there is a research tree, which includes not only locomotives but various techs that provide certain modifiers (faster research, less maintenance time, increase in travel demand, increase in your revenues, etc.)
* you have competitors. they can be very aggressive depending on difficulty level, but are dumb as rocks. they can buy you out and merge, which will make you lose, but you can also do the same to them, although if given the choice you should probably just liquidate everything they have upon merger because they are dumb as bricks when it comes to network planning.
* the main objective is that each playthrough comes with a checklist of things to do by a certain time. (connect X businesses, deliver X people from A to B without stopping, etc.) This helps avoid the issue of late-game snowballing making the game unfun, because snowballing does not really help with some types of objectives like delivery.
Overall, to me it scratches a slightly different itch. OpenTTD/Chris Sawyer's Locomotion/Train Fever are very open ended and you can kind of do whatever you want. You're given a lot more direction in Railway Empire, which isn't necessarily a bad thing if you want more "game" rather than painting a map. The track laying is quite nice, though it should be noted that trains occupying their space on tracks exclusively is a toggle. If it's off trains can run into each other willy nilly and it doesn't matter.