Thornleigh Quarry & Zig Zag Railway - Historic Engineering Marker #88 Pennant Hills, New South Wales, Australia
By Team MavEtJu on 11-Oct-15. Waypoint GA7568

Thornleigh Quarry & Zig Zag Railway - Historic Engineering Marker #88

The genesis of the Thornleigh quarry arose from the decision by the New South Wales Government to build a railway linking Sydney to Newcastle commencing at Strathfield and running north to the Hunter Valley. Assent was formally given in 1880 for the construction of the Homebush to Waratah railway as it was formally titled by the act, which provided funding for the work.

The contract to construct the Strathfield to Hawkesbury River section of the line was awarded on 1 May 1883 to Amos & Co for a total fee of E445,472.4 This company established its main camp for the workers at Hall's Creek, Thornleigh. Adjacent to it, they also opened a quarry at Thornleigh to supply the ballast, which would be used to provide a firm bed for the railway track. The stone dug from this quarry was not bluemetal nor was it a stone of volcanic origin such as was usually used in such works. It was white metal or vitrified sandstone.

The quarry was at the edge of a steep drop and the route to it was also quite steep. In order to transport the stone to the route of the railway line under construction a zigzag tram line running up to the future site of Thornleigh station was constructed. Many years later, railway enthusiast, C C Singleton lived at Thornleigh. Once he had discovered the existence of this zigzag line to the quarry, he set out to fmd it and was successfully able to rediscover the route of the line. He has provided the most detailed explanation of how the line operated. Trains left the main line just north of Thomleigh station and ,via two zigzags they ran down to the quarry, reversing as required. Hall's camp was situated on a level area west of the present Tillock Street. The line crossed a creek where Singleton was still able to see earthworks in 1965. The quarry level was above that of its railway in order to permit the stone to be dumped straight into the wagons.

Contents of the plaque:

Prominent railway contractors Amos & Co constructed the quarry and zig zag railway in 1883 to supply stone ballast ('white metal' - metamorphosed sandstone) for a southern section of the Homebush (Sydney) to Waratah (Newcastle) railway line. The zig zag overcame the significant climb to the main line near Thornleigh station from the quarry 35 meters below. This railway was the third and last standard gauge zig zag in NSW, the others being on the Great Western Line over the Blue Mountains.

THE INSTITUTION OF ENGINEERS AUSTRALIA, HORNSBY SHIRE COUNCIL, DEPARTMENT OF ENVIRONMENT AND CONSERVATION (NSW) 2006

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For more information, please see the nomination PDF at the Heritage Register at the Engineers Australia website: Nomination