--- a/openttd.c	Fri Dec 29 12:18:43 2006 +0000
+++ b/openttd.c	Fri Dec 29 12:33:26 2006 +0000
@@ -1362,6 +1362,8 @@
 					}
 					CLRBIT(_m[tile].m5, 7);
 					SB(_m[tile].m5, 2, 2, 0);
+					SB(_m[tile].m4, 5, 2, GB(_m[tile].m5, 0, 2));
+					SB(_m[tile].m5, 0, 2, 0);
 				} else { /* Tunnel */
 					SetTileType(tile, MP_TUNNEL);
 				}