 For traffic flow purposes the dispatcher needS to record which sidings are occupied.If a train could not use the main track in Bess (due to maintenance, a stuck switch, a disabled train, or an obstacle blocking the track), it would also be possible for the train to have authority from Anna through Bess Siding through Cloy.This is not done when the main track is available, as there is a speed disadvantage to having the train traverse the slower siding track (including having to stop to throw the switches to enter the siding).