WORLD’S LARGEST WOODEN VIADUCT

The Percy Burn Viaduct was hailed as the tallest tramway bridge in the Dominion when it was opened in 1923. Today, it’s claimed to be the largest timber trestle bridge in the world.

(flickr.com)

The South Coast Walking Track is one of the few public tracks in the South Island that is open during winter. Because it has no alpine section, it’s not subject to closure by snow so is favoured by an increasing number of trampers from all over the world. However, its year round availability is not the main reason for its popularity. Apart from the splendour of the Waitutu Forest, the track features a unique attraction, – the Percy Burn Viaduct.

(flickr.com)

Trampers emerging from the forest stop in amazement when confronted by this unique bridge’s massive proportions. It stands an impressive 36 metres above the gully floor and spans a breathtaking 125 metres from end to end.

(nzhistory.govt.nz)

At an eye popping cost at the time of 5000 pounds, the Percy Burn was the highest of four viaducts built by the Marlborough Timber Company in an awesome project to mill native timber from the huge Waitutu Forest. (The Ormondville Viaduct in Hawkes Bay was even longer and taller, but it was demolished 20 years before the erection of Percy Burn). The almost unbelievable feat of endurance and engineering came to an abrupt end when Port Craig, the town built to house the workers, was evacuated on a cold October day in 1928 after the 20 or so workers were given just 4 days to pack up and leave. Arguably the most isolated town ever occupied in New Zealand, Port Craig only existed a scant seven years. In the 1940s, the steel equipment  that had been used for the milling operation was dismantled and sold for scrap.

BRUTAL LOGGING TECHNIQUES

John Craig’s dream of supplying timber to the world from the vast reserves in the dramatic south west area of New Zealand certainly contributed to a period when his think big scheme looked assured of success. His company imported the latest technology from the United States in the form of an unwieldy log hauler called the Lidgerwood. It efficiently cleared (raped!) the forest in a circular action. Two locomotives were used to transfer the timber to the next location where the process was repeated. The Lidgerwood’s bogies rotated ninety degrees so it could be pushed sideways to free up the main railway lines. The machine’s operation also involved a bewildering network of wires to load the timber on the trains for transport to the largest sawmill in New Zealand.

REMARKABLE LOADING SYSTEM

The latest technology was also employed at the wharf. An aerial loading system carried the mill’s product to the company’s own ships which anchored with a certain amount of difficulty it has to be said, in a designated position offshore. A concrete block on the sea floor stabilised guy wires attached to the ship’s mast. From here, the main transport wire was suspended from a 21 metre tower on the wharf. Logs were then swung across the cold pounding waves below. The concept proved successful. A constant procession of ships loaded Port Craig timber for hungry markets in Dunedin, Christchurch and especially the rapidly growing towns of Auckland and Sydney.

A cantilevered landing stage was erected onshore near the mill at Bluecliffs. This impressive structure allowed passengers, mail and goods to be handled on a wild part of the coast where conventional wharf building would have been almost impossible with the equipment available. The breakwater forged into the sea near the mill itself to form a small harbour was a failure. The currents caused the harbour basin to quickly silt up making birthing of any sizeable vessel impossible. The company had more success on land where they cut 24 kilometres of railway through the dense native bush. This involved forming cuttings and building viaducts.

Port Craig Sawmill 1930 (heritage.org.nz)

FOREST WALK

Trampers walking along the Hump Ridge Track through the Waitutu Forest marvel at the effort undertaken last century to strip the trees from it for profit. The former rail tracks have now become part of the Southern Walking Track which also includes the other three viaducts built at the same time as Percy Burn.

Today, the timbers on the Percy Burn Viaduct are decaying as it falls into a state of collapse. Australian hardwood was originally used because it was stronger than the local material which rotted in the extremely damp conditions of a dense native forest. A group of forward thinking locals in nearby Tuatapere could see the future tourist potential in the unique bridge and formed a group and pushed for restoration. They require $700,000 to make the bridge safe.

The Percy Burn Viaduct is an important tourist attraction in Southern New Zealand and stands as a reminder of a time when native timber was exploited without guilt. It took the world depression of the 1930s to terminate this rape.

Waitutu Forest (flickriver.com)

A GREAT NATIVE FOREST

The Waitutu Forest is now internationally significant. It’s been saved three times from the saw but with an increasing awareness in protecting native flora and fauna, it’s future as a magnificent example of pre-human New Zealand nature, is assured. Buried deep in its sweet smelling interior stands a monument originally built to help exploit and destroy it. Nature however, proved the victor, and the relics to man’s greed only add to the attractions this forest now holds for generations still unborn. I only hope the funds can be found to restore the world’s largest wooden viaduct so future trampers can experience the thrill I felt when, a number of years ago, I walked in awe and trepidation across this engineering marvel rising impressively over the forest in its breathtaking surroundings.

The Port Craig logging enterprise was a financial failure and by the end of the 1930s, the mill had closed and the settlement of Port Craig passed into history. During the brief time of operations, this Southland sawmill was the largest in New Zealand and remains to this day, the most ambitious logging enterprise in New Zealand’s history and is now the country’s most important saw milling heritage site. It would be a great loss if the Percy Burn Viaduct also collapses into history.  With tourism the country’s most important industry, it makes sense to me, that money is found to repair this unique tourist attraction so future visitors can experience the thrill of walking over the world’s tallest wooden viaduct. It would also be a positive outcome for an enterprise that failed to destroy one of the world’s most beautiful forests.

Ceidrik Heward

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