 The descent to the Lithgow Valley was originally proposed by means of a tunnel.In 1866 the tunnel was estimated to be about two miles in length and a figure of $800,000 was set down as the cost of its construction.However, due to the enormous cost, construction time and, as John Whitton, Engineer-in-Chief of the NSW Railways reported at the time, it would have been difficult to get a contractor to undertake such difficult work.