- Make sure we clear the additional railtype bit only for the correct tiles.

- Backup and restore the correct railtype for tiles when newGRFs are reloaded during a game.

(cherry picked from commit f5bf8e69b4fe95519513b934dc1057dc304ce3da)

src/tunnelbridge_map.h

@@ -14,6 +14,7 @@
 
 #include "bridge_map.h"
 #include "tunnel_map.h"
+#include "cmd_helper.h"
 
 
 /**
@@ -57,6 +58,19 @@ static inline bool HasTunnelBridgeSnowOrDesert(TileIndex t)
 	return HasBit(_me[t].m7, 5);
 }
 
+
+/**
+* Is this a rail bridge or tunnel?
+* @param t the tile that might be a rail bridge or tunnel
+* @return true if and only if this tile is a rail bridge or tunnel
+*/
+static inline bool IsRailTunnelBridgeTile(TileIndex t)
+{
+	TransportType tt = Extract<TransportType, 2, 2>(_m[t].m5);
+
+	return IsTileType(t, MP_TUNNELBRIDGE) && (tt == TRANSPORT_RAIL);
+}
+
 /**
  * Tunnel: Places this tunnel entrance in a snowy or desert area, or takes it out of there.
  * Bridge: Sets whether the bridge ramp lies in a snow or desert area.