Adds massive cargo ships to the game, that function similarly to trains. Also adds deep sea oil, oil platforms, tanker ships, train bridges and other water based content.
Isn't there an event called on building an entity, and a way to check in the tile the entity is being placed on to see if it's the right type of rail? You could have it hook to check and make sure trains are not on the sea lanes. Also with the boat and the regular rails.
