Error while running event train-signal-navigation::on_nth_tick(30)
train-signal-navigation/scripts/deliver-control.lua:94: attempt to index a nil value
stack traceback:
train-signal-navigation/scripts/deliver-control.lua:94: in function 'is_train_has_enough_signal'
train-signal-navigation/scripts/deliver-control.lua:263: in function 'call_train'
train-signal-navigation/scripts/deliver-control.lua:321: in function 'exec_navigation'
train-signal-navigation/scripts/deliver-gui.lua:193: in function 'on_nth_tick'
train-signal-navigation/scripts/navigation.lua:20: in function <train-signal-navigation/scripts/navigation.lua:19>
