diff --git a/bridge_map.h b/bridge_map.h
--- a/bridge_map.h
+++ b/bridge_map.h
@@ -127,6 +127,7 @@ TileIndex GetSouthernBridgeEnd(TileIndex
  */
 TileIndex GetOtherBridgeEnd(TileIndex);
 
+uint GetBridgeHeight(TileIndex t);
 
 static inline void SetClearUnderBridge(TileIndex t)
 {