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a tree in front of a building

This imposing structure was built between 1863 and 1867. The Knapsack Viaduct was constructed to transport railway traffic across Jamison’s Creek and into the “little zig zag” train line. This climbed the eastern side of the Blue Mountains to Glenbrook.

The enormous structure stands at 40m tall, is 118m long with seven sandstone arches rising imposingly above the gully. It was built originally at a width of 9m to accommodate a single railway line. The second Engineer-in-Chief for Railways John Whitton designed and built the viaduct which was the largest in Australia at the time.

The railway line travelling up Lapstone Hill was a major engineering feat during this era. A number of other plans had been proposed including horse drawn tram and even simply asking people to walk! The authorities though settled on the “zig zag” rail option despite its steep incline. There were incidents told of the difficulties in using the zig zag including when in 1886 a train lost control on descent injuring 15 people. Despite these setbacks, the line served to revolutionize transportation from Sydney, to the Blue Mountains and then the wider regions of NSW beyond.

The bridge continued to be used for approximately 40 years before the Glenbrook Gorge deviation to the south was completed in 1913. The bridge was widened slightly then began being used for road traffic in 1926 as a section of the Great Western Highway. The extension of the M4 motorway up Lapstone Hill in 1993 meant that it was closed to traffic and has now stood idle for over 20 years. Take a bushwalk for a best day ever in Sydney. #yougottalovesydney