Each entrance/exit points between blocks of this territory to the outside world has an indication which way a train may pass. The triangle acts as an arrow indicating in which direction this point is set. This direction can be either inbound or outbound.
There are options available for a preferred settings – inbound or outbound -, to which it will be turned to when a train has cleared the entry/exit point.
If the block next to the entry/exit is one-directional, so will the entry/exit itself, in which case it can be changed only if the traffic direction of the block has been overridden manually. Entries/exits with entry priority -1 cannot be inbound, so they will only allow outbound travel. Different entry tracks from one entry group can have different priorities determining which of the tracks to be used as entry. These priorities are defined in the territory and cannot be modified.
Extern turned inbound
Extern turned outbound