--- a/functions.h	Tue May 09 08:25:31 2006 +0000
+++ b/functions.h	Tue May 09 09:56:09 2006 +0000
@@ -193,9 +193,8 @@
 bool ScrollMainWindowToTile(TileIndex tile);
 bool ScrollMainWindowTo(int x, int y);
 void DrawSprite(uint32 img, int x, int y);
-uint GetCorrectTileHeight(TileIndex tile);
 bool EnsureNoVehicle(TileIndex tile);
-bool EnsureNoVehicleZ(TileIndex tile, byte z);
+bool EnsureNoVehicleOnGround(TileIndex tile);
 void MarkAllViewportsDirty(int left, int top, int right, int bottom);
 void ShowCostOrIncomeAnimation(int x, int y, int z, int32 cost);
 void ShowFeederIncomeAnimation(int x, int y, int z, int32 cost);

--- a/rail_cmd.c	Tue May 09 08:25:31 2006 +0000
+++ b/rail_cmd.c	Tue May 09 09:56:09 2006 +0000
@@ -349,7 +349,7 @@
 					GetTransportTypeUnderBridge(tile) != TRANSPORT_RAIL ||
 					GetRailBitsUnderBridge(tile) != trackbit ||
 					(_current_player != OWNER_WATER && !CheckTileOwnership(tile)) ||
-					!EnsureNoVehicleZ(tile, TilePixelHeight(tile))) {
+					!EnsureNoVehicleOnGround(tile)) {
 				return CMD_ERROR;
 			}
 

--- a/road_cmd.c	Tue May 09 08:25:31 2006 +0000
+++ b/road_cmd.c	Tue May 09 09:56:09 2006 +0000
@@ -125,7 +125,7 @@
 
 	switch (GetTileType(tile)) {
 		case MP_TUNNELBRIDGE:
-			if (!EnsureNoVehicleZ(tile, TilePixelHeight(tile))) return CMD_ERROR;
+			if (!EnsureNoVehicleOnGround(tile)) return CMD_ERROR;
 
 			if (!IsBridge(tile) ||
 					!IsBridgeMiddle(tile) ||

--- a/tile.h	Tue May 09 08:25:31 2006 +0000
+++ b/tile.h	Tue May 09 09:56:09 2006 +0000
@@ -32,13 +32,6 @@
 uint GetTileZ(TileIndex tile);
 uint GetTileMaxZ(TileIndex tile);
 
-static inline bool CorrectZ(Slope tileh)
-{
-	/* tile height must be corrected if the north corner is not raised, but
-	 * any other corner is. These are the cases 1 till 7 */
-	return IS_INT_INSIDE(tileh, 1, 8);
-}
-
 static inline uint TileHeight(TileIndex tile)
 {
 	assert(tile < MapSize());

--- a/tunnelbridge_cmd.c	Tue May 09 08:25:31 2006 +0000
+++ b/tunnelbridge_cmd.c	Tue May 09 09:56:09 2006 +0000
@@ -608,7 +608,7 @@
 			int32 cost;
 
 			// check if we own the tile below the bridge..
-			if (_current_player != OWNER_WATER && (!CheckTileOwnership(tile) || !EnsureNoVehicleZ(tile, TilePixelHeight(tile))))
+			if (_current_player != OWNER_WATER && (!CheckTileOwnership(tile) || !EnsureNoVehicleOnGround(tile)))
 				return CMD_ERROR;
 
 			if (GetTransportTypeUnderBridge(tile) == TRANSPORT_RAIL) {
@@ -626,7 +626,7 @@
 			/* delete canal under bridge */
 
 			// check for vehicles under bridge
-			if (!EnsureNoVehicleZ(tile, TilePixelHeight(tile))) return CMD_ERROR;
+			if (!EnsureNoVehicleOnGround(tile)) return CMD_ERROR;
 
 			if (flags & DC_EXEC) {
 				SetClearUnderBridge(tile);
@@ -752,7 +752,7 @@
 			IsTransportUnderBridge(tile) &&
 			GetTransportTypeUnderBridge(tile) == TRANSPORT_RAIL) {
 		// only check for train under bridge
-		if (!CheckTileOwnership(tile) || !EnsureNoVehicleZ(tile, TilePixelHeight(tile)))
+		if (!CheckTileOwnership(tile) || !EnsureNoVehicleOnGround(tile))
 			return CMD_ERROR;
 
 		if (GetRailType(tile) == totype) return CMD_ERROR;

--- a/vehicle.c	Tue May 09 08:25:31 2006 +0000
+++ b/vehicle.c	Tue May 09 09:56:09 2006 +0000
@@ -131,30 +131,19 @@
 	const TileInfo *ti = data;
 
 	if (v->tile != ti->tile || v->type == VEH_Disaster) return NULL;
-	if (!IS_INT_INSIDE(ti->z - v->z_pos, 0, TILE_HEIGHT + 1)) return NULL;
+	if (v->z_pos > ti->z) return NULL;
 
 	VehicleInTheWayErrMsg(v);
 	return v;
 }
 
-static inline uint Correct_Z(Slope tileh)
-{
-	// needs z correction for slope-type graphics that have the NORTHERN tile lowered
-	return CorrectZ(tileh) ? TILE_HEIGHT : 0;
-}
 
-uint GetCorrectTileHeight(TileIndex tile)
-{
-	return Correct_Z(GetTileSlope(tile, NULL));
-}
-
-bool EnsureNoVehicleZ(TileIndex tile, byte z)
+bool EnsureNoVehicleOnGround(TileIndex tile)
 {
 	TileInfo ti;
 
 	ti.tile = tile;
-	ti.z = z + GetCorrectTileHeight(tile);
-
+	ti.z = GetTileMaxZ(tile);
 	return VehicleFromPos(tile, &ti, EnsureNoVehicleProcZ) == NULL;
 }