A double-track tunnel with restricted clearances is sometimes singled to form a single track tunnel with more generous clearances, such as the Connaught Tunnel in Canada or the Tickhole Tunnel in New South Wales, Australia. In the case of the Tickhole Tunnel a new single-track tunnel was built and the two tracks in the original tunnel were replaced by one track in the centreline of the tunnel. Another case where this was necessary was the Hastings Line in the United Kingdom, where the tunnels were eventually singled to permit the passage of standard British-gauge rolling stock. Before the singling, narrow-bodied stock, specially constructed for the line, had to be used.