Train Track balancing

Basically, if I have multiple ways to get from A to B from what i understand and have seen so far trains will always choose the shortest route.
Probably have it be optional, maybe even a global setting you can turn on and off mid playthrough.
IDK how intensive this would be or if it would be difficult to implement, but if every track had a number that ticked up with every train that passed and slowly downward overtime, and trains preferred tracks with Lower numbers, then tracks with high traffic would discourage trains from pathing over them, and instead find alternate routes. This would also allow player to set track priorities, by setting said number to rest higher or lower than default. Could probably track just at junctions too instead of every track. Obviously distance would also have to be taken in to account, maybe the shortest path is normal, the second shortest adds one to the traffic number, third shortest add 2 and so on, maybe not linear but something like that.