Port Craig Viaducts (including the Percy Burn Viaduct)
Engineering Work (eg road, bridge, sawmill, dam)
Port Craig Viaducts
Four timber viaducts, of which the Percy Burn Viaduct is the largest (see below for further details), were constructed in the early 1920's as part of a short-lived bush tramline that served Southland's Port Craig logging and sawmill operations. The other bridges were all the work of engineer Jim Kane and are:
- the Edwin Burn Viaduct, 22 metres (m) high and 48.9m long
- the Francis Burn Viaduct, 13.6m high and 51.5m long
- and the Sandhill Point Viaduct 17m high and 59m long
From 1918 Port Craig was the site of two Marlborough Timber Company mills. When built, one of these mills was the largest and most modern mill in New Zealand, capable of producing seven to eight million feet of timber per year. Most of the timber milled seems to have been rimu, because while the forest had a plentiful supply of Southland beech there was no demand for this timber.
In 1928 both mills were forced to close because of falling timber prices. A skeleton staff was left to keep the equipment in working order, but when timber prices did not recovered after the Great Depression, the mills were dismantled and moved elsewhere.
While the mills operated, Maori land and some State Forest between Port Craig and Wairaurahiri River was logged, the timber being transported by tram. The company constructed the four large viaducts to carry the tram rails over deep streams.
This group of viaducts is a good example of engineering in the early 20th century and, recently redecked for safety, remain as important relics of sawmilling in Southland. They now serve trampers in the Waitutu State Forest.
Department of Conservation (www.doc.govt.nz) manages these structures.
Percy Burn Viaduct
One of the biggest timber viaducts ever built in New Zealand, the Percy Burn Viaduct is 125 metres long by 36 metres high. It is made of Australian hardwood, and was opened in 1923. The tall timber piers have concrete footings, and diagonal and longitudinal steel bracing. The contractor for this viaduct was Chester Construction Company.
The timber has withstood the conditions in this relatively wet district reasonably well. However, in 1993-94 approximately 16 per cent of the existing timber was replaced with pinus radiata in order to maintain the integrity of the structure. Funds for this costly project were raised by the Port Craig Viaducts Trust.
It is thought that the Percy Burn Viaduct is one the highest remaining timber trestle bridges in the world.
Percy Burn viaduct: film clip (www.teara.govt.nz)
This place has been recognised by Heritage New Zealand as a Category 1 historic place (List no.9234):
Port Craig Sawmill and Settlement: New Zealand Heritage List/Rarangi Korero information (www.heritage.org.nz).
IPENZ “Engineering to 1990” project
This item of New Zealand’s engineering heritage was recognised as part of the IPENZ “Engineering to 1990” project which the Institution organised to help celebrate the country’s sesquicentenary in 1990. A plaque was unveiled to mark the significance of the Percy Burn Viaduct as part of the development of the nation.
W. Bird, Viaducts Against the Sky: The story of Port Craig, Invercargill, 1998
T. Butler, 'Port Craig Viaducts Engineering Assessment and Conservation Plan,' 3rd Australasian Engineering Heritage Conference (2009). [PDF, 739 KB]
R. Egerton, 'Heritage Management at the Port Craig Sawmill Complex: Success and Challenges,' 3rd Australasian Engineering Heritage Conference (2009). [PDF, 647 KB]
G. Thornton, Bridging the Gap: Early bridges in New Zealand, 1830-1939. Auckland, 2001, pp.44-46
Waitutu State Forest, 20 kilometres (km) west of Tuatapere, Southland
The wooden viaducts are available for viewing at all times. Percy Burn is 18 km from the start of the coastal track from Track Burn to the Waitutu River.
Nature of Engineering
Infrastructure (incl. Road, water, ports), Transport (Road, sea, air, incl vehicles)
Lat: -46.24 Long: 167.30