Allows much easier control of path-finding selection of routes for trains to travel, as well as easy prevention of trains taking "short-cuts" through stations or sidings they aren't supposed to be on.
Picture example of what could be avoided
Red - Path the train currently takes.
Green - Path I would like the train to take.
Having a piece of rail to make the red path "longer" than it actually is easily remedies this sort of problem.
