Queanbeyan railway bridges over Queanbeyan and Molonglo Rivers

The Queanbeyan railway bridges over Queanbeyan and Molonglo Rivers are two heritage-listed railway bridges on the Bombala railway line at Queanbeyan-Palerang Region, New South Wales, Australia. They were built in 1926. The first bridge crosses the Queanbeyan River from Queanbeyan to Queanbeyan East at -35.3424°N, 149.2317°W, while the second bridge (approx 8 km to the east crosses the Molonglo River at Burbong (now Carwoola) at -35.3371°N, 149.3191°W. The property is owned by RailCorp, an agency of the Government of New South Wales. It was added to the New South Wales State Heritage Register on 2 April 1999.

History
The bridges were first built by contractors Johnston & Co. in 1885-87 along with the extension of the railway from Bungendore to Michelago through Queanbeyan. The Molonglo River bridge was completed in May 1886 and the Queanbeyan River bridge in July 1887, both opening with the line in September 1887. The original bridges consisted of arched hardwood timber girders on brick piers and stone abutments, featuring four spans (Molonglo River) and five spans (Queanbeyan River) of 80 ft each. The stone for the abutments came from the quarries at Pyrmont in Sydney. A temporary bridge over the Queanbeyan River during construction was reported at the time to be the largest temporary railway bridge ever constructed in New South Wales.

The bridges were completely rebuilt in 1926-27 at a cost of £19,000, reusing the foundations of the original bridge. Both bridges were of the Warren deck steel truss type, consisting of four 44 ft. steel spans on the approaches to each side with three (Queanbeyan River) and two (Molonglo River) spans of 90 ft comprising the main bridge. The timbers of the original bridge were still in "a remarkable state of preservation" when replaced, such that it could not be cut in some cases. The bridge upgrade allowed a heavier type of engine to be run on the line.

The Molonglo River bridge is sometimes known as the Burbong bridge, Burbong being a historical name for its location.

Heritage listing
The Queanbeyan rail bridges over Queanbeyan and Burbong Rivers was listed on the New South Wales State Heritage Register on 2 April 1999 having satisfied the following criteria.

The place possesses uncommon, rare or endangered aspects of the cultural or natural history of New South Wales.

This item has some historical rarity due its association with the 1887 Cooma Railway and the reuse of the original foundations for the 1926 replacement trusses. The Warren deck trusses are relatively rare because there are only four other railway sites in NSW with this type of superstructure.