diff --git a/src/order_func.h b/src/order_func.h
--- a/src/order_func.h
+++ b/src/order_func.h
@@ -24,6 +24,7 @@ void DeleteVehicleOrders(Vehicle *v, boo
 bool ProcessOrders(Vehicle *v);
 bool UpdateOrderDest(Vehicle *v, const Order *order, int conditional_depth = 0, bool pbs_look_ahead = false);
 VehicleOrderID ProcessConditionalOrder(const Order *order, const Vehicle *v);
+uint GetOrderDistance(const Order *prev, const Order *cur, const Vehicle *v, int conditional_depth = 0);
 
 void DrawOrderString(const Vehicle *v, const Order *order, int order_index, int y, bool selected, bool timetable, int left, int middle, int right);