--- a/rail_cmd.c	Sat Dec 30 12:49:54 2006 +0000
+++ b/rail_cmd.c	Sat Dec 30 12:55:45 2006 +0000
@@ -247,6 +247,13 @@
 	SET_EXPENSES_TYPE(EXPENSES_CONSTRUCTION);
 
 	switch (GetTileType(tile)) {
+		case MP_RAILWAY_BRIDGE:
+			/* We can build custombridgeheads only if we have a horizontal ramp ... */
+			if (!HASBIT(BRIDGE_HORZ_RAMP, tileh)) return CMD_ERROR;
+
+			/* In which case we can assume the tile to be flat */
+			tileh = 0;
+			/* FALL THROUGH */
 		case MP_RAILWAY:
 			if (!CheckTrackCombination(tile, trackbit, flags) ||
 					!EnsureNoVehicle(tile)) {