Giant truck hits Northland roads

The giant truck - made up of three trucks coupled to a 112-wheel trailer carrying an 85-tonne transformer - powers up a hill at Umawera on Monday afternoon. Photo / Peter de Graaf

What has 142 wheels, pumps out 1590 horsepower, weighs 190 tonnes and needs three drivers to keep it on the road?

The answer is the biggest thing ever seen on Northland roads.

Click on the image below to see a clip on the truck climbing a hill at Umawera:

The supertruck that traversed Northland this week to bring a new transformer to Kaitaia, part of a multi-million-dollar rebuild of Top Energy's power network in the Far North, consisted of three "prime movers" (that's trucks to the rest of us) coupled to a 112-wheel trailer.

At 85 tonnes the transformer is thought to be the heaviest load transported on Northland roads.

The trailer was pulled by a Mack CL600 and a Scammell S64; pushing from behind was a Scania 530. Each truck is capable of 530 horsepower; all up the beast weighed 190 tonnes.

The monster truck travelled from Ports of Auckland to Mangamuka on Monday, making good pace on straight sections of highway but dropping to walking pace at the sharpest bends.

Challenges on day one included the one-lane bridge at Rangiahua with only centimetres to spare between the trailer and the guard rails on either side.

Tranzcarr Heavy Haulage manager Mike van Ravenstein said the Manukau-based company had transported far heavier cargo but the transformer was "getting up there" in terms of the biggest thing that could be moved on Northland roads.

The real challenge was getting it over the Mangamuka Ranges on Tuesday. The trailer had to be reduced in length by four axles for the Mangamukas' twisting terrain, a process which took most of the day and involved jacking up the transformer.

It arrived in Kaitaia just before 7pm where it was unloaded using a gantry crane system.

Mr van Ravenstein said three months of planning had gone into the job. He had carried out a thorough route survey but found the Mangamukas provided the only possible route.

"It's been a bit of a headache but it's all coming together," he said.

The new transformer is part of a major upgrade of the Far North's power network.

Top Energy spokesman Peter Heath said the heaviest load previously shifted on Northland roads was believed to be a 79-tonne component of Kaitaia's triboard mill.

While the highway over the Mangamukas was not New Zealand's steepest road, it was one of the most challenging for heavy transport.

Kaitaia's existing transformer was bought second-hand in 1979 and developed a significant fault last year.

The new transformer would be operational by the end of March and was expected to last 80 years.

It would convert the 110kV supply entering Kaitaia to 33kV, then feed substations at Okahu Rd, Pukenui, Taipa and the JNL timber mill.

Mr Heath said it was more efficient than the existing unit and could be easily scaled up if Kaitaia's power demand increased in future.

It was built by Alstom Grid in Jakarta, Indonesia. A new transformer for Ngawha power station was made in the same factory and arrived on the same ship last Friday.