diff --git a/bridge_map.h b/bridge_map.h
new file mode 100644
--- /dev/null
+++ b/bridge_map.h
@@ -0,0 +1,37 @@
+/* $Id$ */
+
+#ifndef BRIDGE_MAP_H
+#define BRIDGE_MAP_H
+
+#include "macros.h"
+#include "map.h"
+#include "rail.h"
+#include "tile.h"
+
+
+static inline void SetClearUnderBridge(TileIndex t)
+{
+	SetTileOwner(t, OWNER_NONE);
+	SB(_m[t].m5, 3, 3, 0 << 2 | 0);
+}
+
+static inline void SetWaterUnderBridge(TileIndex t)
+{
+	SetTileOwner(t, OWNER_WATER);
+	SB(_m[t].m5, 3, 3, 0 << 2 | 1);
+}
+
+static inline void SetRailUnderBridge(TileIndex t, Owner o, RailType r)
+{
+	SetTileOwner(t, o);
+	SB(_m[t].m5, 3, 3, 1 << 2 | TRANSPORT_RAIL);
+	SB(_m[t].m3, 0, 4, r);
+}
+
+static inline void SetRoadUnderBridge(TileIndex t, Owner o)
+{
+	SetTileOwner(t, o);
+	SB(_m[t].m5, 3, 3, 1 << 2 | TRANSPORT_ROAD);
+}
+
+#endif