diff -r 220d67208783 -r afa6f92a71fd rail_cmd.c
--- a/rail_cmd.c	Wed Dec 27 12:22:25 2006 +0000
+++ b/rail_cmd.c	Wed Dec 27 12:38:02 2006 +0000
@@ -247,36 +247,13 @@
 	SET_EXPENSES_TYPE(EXPENSES_CONSTRUCTION);
 
 	switch (GetTileType(tile)) {
-		case MP_TUNNELBRIDGE:
-			if (!IsBridge(tile) ||
-					!IsBridgeMiddle(tile) ||
-					AxisToTrackBits(OtherAxis(GetBridgeAxis(tile))) != trackbit) {
-				// Get detailed error message
-				return DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
-			}
-
-			if (IsClearUnderBridge(tile)) {
-				ret = CheckRailSlope(tileh, trackbit, 0, tile);
-				if (CmdFailed(ret)) return ret;
-				cost += ret;
-
-				if (flags & DC_EXEC) SetRailUnderBridge(tile, _current_player, railtype);
-			} else if (IsTransportUnderBridge(tile) &&
-					GetTransportTypeUnderBridge(tile) == TRANSPORT_RAIL) {
-				return_cmd_error(STR_1007_ALREADY_BUILT);
-			} else {
-				// Get detailed error message
-				return DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
-			}
-			break;
-
 		case MP_RAILWAY:
 			if (!CheckTrackCombination(tile, trackbit, flags) ||
 					!EnsureNoVehicle(tile)) {
 				return CMD_ERROR;
 			}
 			if (!IsTileOwner(tile, _current_player) ||
-					!IsCompatibleRail(GetRailType(tile), railtype)) {
+					GetRailType(tile) != railtype) {
 				// Get detailed error message
 				return DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
 			}
@@ -366,20 +343,6 @@
 	SET_EXPENSES_TYPE(EXPENSES_CONSTRUCTION);
 
 	switch (GetTileType(tile)) {
-		case MP_TUNNELBRIDGE:
-			if (!IsBridge(tile) ||
-					!IsBridgeMiddle(tile) ||
-					!IsTransportUnderBridge(tile) ||
-					GetTransportTypeUnderBridge(tile) != TRANSPORT_RAIL ||
-					GetRailBitsUnderBridge(tile) != trackbit ||
-					(_current_player != OWNER_WATER && !CheckTileOwnership(tile)) ||
-					!EnsureNoVehicleOnGround(tile)) {
-				return CMD_ERROR;
-			}
-
-			if (flags & DC_EXEC) SetClearUnderBridge(tile);
-			break;
-
 		case MP_STREET: {
 			if (!IsLevelCrossing(tile) ||
 					GetCrossingRailBits(tile) != trackbit ||
@@ -617,6 +580,8 @@
 	if (CmdFailed(ret)) return CMD_ERROR;
 	cost = ret;
 
+	if (MayHaveBridgeAbove(tile) && IsBridgeAbove(tile)) return_cmd_error(STR_5007_MUST_DEMOLISH_BRIDGE_FIRST);
+
 	d = AllocateDepot();
 	if (d == NULL) return CMD_ERROR;
 
@@ -1414,6 +1379,7 @@
 			);
 		}
 	}
+	DrawBridgeMiddle(ti);
 }
 
 
@@ -1513,19 +1479,11 @@
 static void *SignalVehicleCheckProc(Vehicle *v, void *data)
 {
 	const SignalVehicleCheckStruct* dest = data;
-	TileIndex tile;
 
 	if (v->type != VEH_Train) return NULL;
 
-	/* Find the tile outside the tunnel, for signalling */
-	if (v->u.rail.track == 0x40) {
-		tile = GetVehicleOutOfTunnelTile(v);
-	} else {
-		tile = v->tile;
-	}
-
 	/* Wrong tile, or no train? Not a match */
-	if (tile != dest->tile) return NULL;
+	if (v->tile != dest->tile) return NULL;
 
 	/* Are we on the same piece of track? */
 	if (dest->track & v->u.rail.track * 0x101) return v;
@@ -1541,15 +1499,18 @@
 	dest.tile = tile;
 	dest.track = track;
 
-	/** @todo "Hackish" fix for the tunnel problems. This is needed because a tunnel
-	 * is some kind of invisible black hole, and there is some special magic going
-	 * on in there. This 'workaround' can be removed once the maprewrite is done.
-	 */
-	if (IsTunnelTile(tile)) {
-		// It is a tunnel we're checking, we need to do some special stuff
-		// because VehicleFromPos will not find the vihicle otherwise
-		TileIndex end = GetOtherTunnelEnd(tile);
-		DiagDirection direction = GetTunnelDirection(tile);
+	/* Locate vehicles in tunnels or on bridges */
+	if (IsTunnelTile(tile) || IsBridgeTile(tile)) {
+		TileIndex end;
+		DiagDirection direction;
+
+		if (IsTunnelTile(tile)) {
+			end = GetOtherTunnelEnd(tile);
+			direction = GetTunnelDirection(tile);
+		} else {
+			end = GetOtherBridgeEnd(tile);
+			direction = GetBridgeRampDirection(tile);
+		}
 
 		dest.track = 1 << (direction & 1); // get the trackbit the vehicle would have if it has not entered the tunnel yet (ie is still visible)
 
@@ -1559,9 +1520,9 @@
 		// check for a vehicle with that trackdir on the end tile of the tunnel
 		if (VehicleFromPos(end, &dest, SignalVehicleCheckProc) != NULL) return true;
 
-		// now check all tiles from start to end for a "hidden" vehicle
+		// now check all tiles from start to end for a warping vehicle
 		// NOTE: the hashes for tiles may overlap, so this could maybe be optimised a bit by not checking every tile?
-		dest.track = 0x40; // trackbit for vehicles "hidden" inside a tunnel
+		dest.track = 0x40;   //Vehicle inside a tunnel or on a bridge
 		for (; tile != end; tile += TileOffsByDiagDir(direction)) {
 			if (VehicleFromPos(tile, &dest, SignalVehicleCheckProc) != NULL)
 				return true;