Wednesday, May 9, 2012

Whipple Trusses at Lewisham

Lewisham Viaduct circa 1886 
On our previous walk along the Hawthorne Canal in Sydney's inner-west, we came across the above photo of the construction of the iron Whipple truss railway viaduct which crossed Long Cove Creek, west of Lewisham.

This put me in mind of some old railway trusses that I had previously seen in the area. But where are they now?

Continuing along the Canal across Parramatta Road, we duly located the Lewisham Railway Viaduct at Longport Street in Lewisham. (photo below). This shows a combination of the past, present and future transport history of Sydney. Firstly we can see the old Whipple Trusses to the left, then above, the plate web girders of the current bridge, and to the right, the rail lines for the extension to the Light Rail.

Lewisham Railway Viaduct May 2012 
The Whipple Trusses
When the main railway line from Sydney to Granville was opened on 26 September 1855, the original viaduct over Long Cove Creek was an  8-span stone arch structure (shown being demolished in the top photo). This was  replaced in 1886 by three pairs of Whipple trusses. These were designed by Max Thomson for the New South Wales Government Railways and were significant in that they pioneered the introduction of American bridge technology on our railways. They were pin-jointed trusses of the type developed in America by Squire Whipple.

When they were replaced in 1993 after 107 years of service on the main railway line, one pair of the Whipple trusses was placed on display on the southern side of the Lewisham Viaduct in Grosvenor Street, as a testament to their engineering heritage . An Historic Engineering Marker was dedicated at this spot in 1994 by the Institute of Engineers Australia and the State Rail Authority, NSW.

Whipple Trusses in Grosvenor Street, Lewisham  - May 2012
History Services NSW in its Government Contracts and Contractors Database has details of a major contract awarded to G.H Royce & Co, by the NSW Government Railways in 1884 for the "Construction and supply of the whole ironwork required for the superstructure of a new viaduct over Long Cove Creek, Petersham, Great Southern Railway". [NB At the  time of construction, Lewisham Railway Station had not been built so reference was made to the nearest  station at Petersham].

In the Government Contracts and Contractors Database, there are also some 60 records of contracts awarded for work on the Petersham section of the main railway line in 1880s and 1890s.

As a footnote, descending into the Cadigal Reserve, it is possible to walk under the massive structure of the Lewisham Viaduct which boasts four types of bridge engineering. (Photo below).

View of Lewisham Viaduct from Cadigal Reserve - May 2012
A very interesting day of Railway history!

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