Error while running event traintunnels::on_train_changed_state (ID 23)
traintunnels/control.lua:1100: bad argument #1 of 5 to 'find' (string expected, got nil)
stack traceback:
[C]: in function 'find'
traintunnels/control.lua:1100: in function <traintunnels/control.lua:1042>
