was remodelled with a new parallel, more steeply sloped line to the west. Both of the lines of the Top Road extension are clearly legible. The line of track (now without rails) goes through well executed rock cuttings on the standard walk along Top Road from Knapsack Street and Skarratt Park. There is a pleasing stone culvert to the south of Lucasville platform. Lucasville station was built in 1877 for the Minister for Mines, John Lucas who had a holiday home nearby. The culvert, which is still in operation, utilises a rock-cutting on the west side to divert run-off water deep under the track in a square channel constructed of stone blocks. The water then runs down a steep gully to the east. To the west of the Upper Road there is a series of low sandstone terrace walls which probably marked the boundary between Lucasville estate and the railway. The ZigZag is largely surrounded by bushland, interspersed with impressive views east to Sydney. The setting provides a striking sense of the nineteenth-century journey over the mountains as the traveller was entering into a wilderness. At the southern entry to the Top Road of the ZigZag, at the end of Knapsack Street, there is a gate to inhibit vehicle access. Just beside this gate, on the northern side, there are four surviving sleepers and metal spikes, all that survives from the original railway track. The rail route across the mountains extended as far as Wentworth Falls (then called "Weatherboard") by 1867 but the Lapstone Zig Zag, which included Lucasville station, soon ran into problems: the length of the top points and bottom points limited the length of trains and the single track meant that trains travelling in opposite directions had to stop at crossing points. The first crossing point after Lapstone Zig Zag was at Wascoe's Siding at what is now Glenbrook station. The Lapstone ZigZag was the first ZigZag constructed on any main-line railway anywhere in the world. The idea on which Whitton built came from the Indian railways. A friend of his, Solomon Tredwell, had in 1859 started the construction of half a ZigZag (with a reversing line and stone viaducts) at Bhore Ghat on the Bombay to Poona line. Although Tredwell died in 1859, his widow saw the half ZigZag to completion in 1863, employing 42,000 men, and this feat was reported at some length in The