Archive Article: 1997/08/02

2 August 1997

A novel tracked tractor – the Case IH Steiger Quadtrac – is set to make its mark on two Essex farms this autumn. Peter Hill reports.

RENEWED interest in the power output of US-style Prairie tractors and the low ground pressure advantages of tracks has been forged in a machine that makes its commercial working debut on farms this year.

The 360hp (SAE gross) Case IH Steiger Quadtrac is based on the wheeled articulated tractors built at the Case-Steiger operation in North Dakota. But instead of wheels, the Quadtrac has a triangular track frame at each corner.

This unique configuration means that, unlike rigid chassis tractors converted to tracks, the tractors original bend in the middle steering system can be used. The only major change is to the axles which need different reduction gearing.

The large track area reduces ground pressure and gives plenty of traction in favourable conditions, says Case, especially since the four independent track frames can oscillate to some extent over ground undulations. That should also help give drivers a more comfortable ride, particularly on secondary cultivations work.

Tom and Robert Howie, based at Tolleshunt Major, near Maldon, are waiting for their Quadtrac to make the journey across the Atlantic. They specialise in arable contract management, farming a total of 1,420ha (3,508 acres).

Down-to-earth reasoning is behind the purchase of the big tractor, which is significantly more powerful than the high horsepower conventional tractors used at present.

Last year, all cultivations and drilling work was performed by three John Deeres – a 260hp 8400, a 228hp 4955 and an ageing 215hp 4850. The Quadtrac will replace the two older tractors, which should bring a reduction in long-term power, maintenance, labour and running costs.

"Weve discounted big articulated four-wheel drive tractors before, simply because of the weight and lack of mobility on duals," says Mr Howie. "Weve also looked at conventional rubber tracked crawlers, but have been put off by the scuffing and power drag during headland turns. The Quadtrac combines the advantages of both types of tractor without the drawbacks."

The Quadtrac concept may be new but, being based on the Case 9370/9380 Steiger chassis, uses proven components so reliability should not be a factor.

They may be big and powerful but they are also relatively simple – two coupled frames with engine, axles and cab attached. The introduction of better-appointed cabs and powershift gearboxes has increased their appeal by meeting driver expectations this side of the Atlantic.

The Howie brothers grow wheat and barley, oilseed rape, linseed, sugar beet, potatoes, beans, sweet corn and peas on a dozen blocks of land stretching 32km end-to-end. That puts a premium on mobility; the John Deere 8400 copes on large Trelleborg singles but duals on the other two have been a nuisance, says Robert Howie.

With an overall width of 3.04m and a road speed of 30kph, the Quadtrac raises no concerns on this count. At the same time, the four individual track sections bring ground pressure down to an impressive 0.34bar (5psi).

Soils ranging from gravel to heavy London clay mean compaction is a significant concern on the Howies heavier land.

"We do sample digs in the spring to decide fields that need subsoiling after harvest, then build that into the cultivations schedule," notes Robert Howie. "Minimising compaction in the first place is clearly worthwhile, and the Quadtrac should help in that respect."

Land destined for spring crops is ploughed but discing is the favoured approach for autumn-sowing as the most time and cost-efficient option.

Subsoiling, where necessary, slots between passes with a set of Simba discs which combine 3B and 4B gangs for a progressive action, plus a ring press to consolidate the soil and some moisture. Seed bed working and sowing is then completed using an 8m Vaderstad disc drill.

This approach will be streamlined to some extent this year with the purchase of a Maxi-Lift 450-series cultivator-subsoiler combination from Tim Howard Engineering.

This 5.4m wide trailed unit, with its nine subsoiler tines on a swept-back folding frame, will increase subsoiling capacity for one thing, releasing the Quadtrac for heavy discing work later on.

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