@@ -527,6 +527,7 @@ CommandCost CmdBuildTunnel(TileIndex sta
for (;;) {
end_tile += delta;
if (!IsValidTile(end_tile)) return_cmd_error(STR_TUNNEL_THROUGH_MAP_BORDER);
end_tileh = GetTileSlope(end_tile, &end_z);
if (start_z == end_z) break;