Lost trains ignore (block) exit signals

	If trains are lost they ignore block exit signals, blocking junctions

	with presignals. This is caused because the path finders cannot tell

	where the train needs to go. As such a random direction is chosen at

	each junction. This causes the trains to occasionally to make choices

	that are unwanted from a player's point of view.

	This will not be fixed because lost trains are in almost all cases a

	network problem, e.g. a train can never reach a specific place. This

	makes the impact of fixing the bug enormously small against the

	amount of work needed to write a system that prevents the lost trains

	from taking the wrong direction.