As for the trains, take the quality of them with a pinch of salt. They would just be 'hero renders' and not necessarily representative of the final product! That doesn't mean they won't look good, but those screenshots would be the high poly models, not in the game engine...
Its difficult to explain what they do with them unless you know about modelling, they will have a high poly mesh and a low poly mesh and will 'bake' the detail of the high poly into the low poly, creating a normal and sometimes a displacement map to simulate the bumps and shadings of the high poly... That probably made no sense, but the point is the trains will probably look less impressive in game, you also have the point those pictures are renders of the train most likely not in game engine, so will look much prettier..