Deadlock prevention

Inputs:

• position and train_on_track
• pre_next_segment
• moving
• track_speeds


Features:

• Take an alternative route (route == 1): on full station (KH, KH_REV, IC, OC) or other special for deadlocks prevention
  
  • e.g. if KH_ST is full and the KIO_LN are occupied by incoming (into KH) trains a train leaving KH should always leave through KH
• Lock the entrance to KH_LN and KH_LN_REV and the corresponding exit of the turnout track: more than two trains travel in the opposite direction of KH
• Assign a random destination to trains: that are in a station, have no destination and are blocking other trains
  • random_destination is calculated deterministcly
  • can be disabled for each train by setting no_forced_direction
• KH_ST is full in one direction and the KIO_LN in the opposite direction/ exit of the turnout track are locked: depends on how busy KH_LN is and if someone wants to enter from KH_LN (same for REV)
• Lock opposite direction in KH: a train in the KH pass may have to wait for a long time if trains are looping in the opposite direction, so wait for two trains (waiting_bound_KH in KH_Deadlock_Prevention) and then enable its movement
• Set a random destination for each train (random_mode == true): sets destination if train doesn't have one