I have some suggestions wen you are introducing the x crossing could you also create the plausibility of making it a double/outside slip.
also a tree way switch would be cool.
also the plausibility of connecting tram and standard rail would be awesome i can give multiple plausibility of hybrid vehicles.
as a addition of the future there could be ertms track added vehicle must be ready fore these track or the track must be brought back to level 3 by placing signals.
If introducing harbors could there be a train yard with with a hill for sorting the wagons. This would need tho bring a new mechanism that allows the station dictating the cargo instead of the trains.