Thornleigh Quarry & Zig Zag Railway

Located near the end of De Saxe Close, Thornleigh, within Berowra Valley Regional Park are the remnants of Thornleigh Quarry. The quarry began when prominent railway contractors Amos & Co won the contract to construct the Homebush to Waratah railway line in 1883. They used the quarry to obtain white metal – metamorphosed sandstone for ballast. The quarry is located within 1 km, North West of Thornleigh Station, through some steep terrain, 30 m below the station level. To overcome problems with a steep gradient, a zig zag siding was built to the quarry from the main line near Thornleigh Station. However, land subdivision has since occurred and most of the line (except for a short section adjacent the quarry) has been built over.

This was the third and last zig zag railway built in NSW. The other two being over the Blue Mountains at Lapstone in 1867 and the Great Zig Zag at Lithgow in 1869.

The quarry is adjacent to a cycleway constructed by Hornsby Shire Council. The National Parks & Wildlife Service has installed interpretive signs relating to the zig zag railway and the quarry.

Plan of Thornleigh Zig Zag by Adele Taylor.

Plaque Unveiling.

The site has been developed as a walking trail and bike path.

The Engineers Australia plaque at Thornleigh.

A wider view of the plaque and its mounting.

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Thornleigh Quarry & Zig Zag Railway location map.

Engineering Heritage Recognition Program

Interpretation panels have been installed by the National Parks and Wildlife Service.

Marker Type	Historic Engineering Marker (HEM)
Award Date	1 November 2006
Heritage Significance	This was the third and last zig zag railway built in NSW. The other two being Lapstone in 1867 and the Great Zig Zag at Lithgow in 1869.
Nomination Document	Available here.
Supporting Document	Available_here.
Interpretation Panel 1	Available_here
Interpretation Panel 2	Available_here