calls for exceptional skill, first-class quipment, and is definitely not
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for the faint-hearted. Gibb Grace finds out that sort of machinery you need if you plan to compete in the specialised
business of timber haulage.
Ihanks to the efforts of the Forestry Commission and many private landowners there is a lot of UK timber to be felled and timber hauliers are being kept busy. Timber bulk commodity and most hauliers paid on a tonnage basis, so this seclends itself to a 44-tonne operation. -Iowever, there is no universal agreeit about which is the best tractor con-ation. When timber has to be col3d from the forests where it has been d you might think that 6x4 tractors indispensable. In fact they are less ular than they used to be, with 6x2s 3ming the order of the day, his is because they are seen as more oeuvrable, easier to maintain and or. Also, some access roads are 'oving to the point where hauliers are ig that if a site is not suitable for a 6x2 it is not suitable for any vehicle. That , traction at 44 tonnes is paramount a 6x2 with a lifting tag axle that shifts load to the drive axle on demand is :rally the tractor of choice.
' the tractor configuration is impor tant, the choice of trailer is critical— especially at 44 tonnes. Timber trailers have evolved from skeletal trailers over the years and now are a recognised design in their own right Dennison Trailers of Lancaster has been closely involved with the business for many years; it refers to its products as "two-member timber skeletals". The two members" are the trailer's main beams, which can be set at BOOmm centres to accommodate dual tyres, or at 1,200mm centres to suit wide-singles. While different hauliers choose different tyre equipment, the current trend is definitely towards wide-singles.
Mark Atkinson of Atkinson Trailers in Edinburgh says the most important factors for timber hauliers are payload, strength and reliability. This trade-off has been pushed to the limit in the past, he reports, and a combination of higher weights and tractors with lifting third axles has really put the trailer neck design to the test.
A Dennison Trailers spokesman agrees, and points out that its necks are 240mm, or getting on for 10 inches, thick. Sheer weight of material is not necessar ily the answer, however, and Atkinson says that newer trailers tend to have fewer cross-members so that they can flex more easily to handle the stresses when running over rough terrain.
Choice of running gear is important, and the 24-tonne triaxle bogie with air suspension is as popular here as in general haulage; not least because it is a prerequisite for 44 tonne operation. Not so long ago the bogies would have been built up by the trailer manufacturer but nowadays bogies come ready assembled, complete with axles and suspension arms, ready to be welded to the frame and piped into the braking system.
Dennison will supply any make of bogie, but its spokesman says Mentor and BPW are the most popular. Both Mentor and BPW can supply axles to suit single and dual wheels equipped with either drum or disc brakes. The choice of brake is down to operator preference. but discs are gaining ground because of their lower servicing costs.
The trailer manufacturers make the basic structure, which is then customised to suit individual operations by specialist companies such as Outreach of Falkirk and Caledonian Forestry Services of Auchterarder.
The most important part of any timber trailer is its U-shaped bolsters, comprising steel horizontal cross-members and two vertical pins which retain the load. Bolsters vary in load capacity, but a pair of bolsters can handle any length of timber, provided they are correctly spedfled. Shorter lengths of timber will weigh less than longer lengths, but a larger number of lighter bolsters will be needed to retain the load. in such a payloadconscious operation every kilogramme counts, and lightweight bolsters such as the Alucar range, which uses aluminium pins, can save weight.
The cross-members (or bunk frames, as they are called) weigh between 60-90kg and aluminium pins weigh between 30-40kg each, so it is clearly important to get the number of bunk frames right. Some loading flexibility is possible, as the bunk frames can be attached to the trailer chassis using 'firm', 'quick' or 'gliding' fixings, but in practice moving them is not a quick job and they tend to remain fixed.
The other indispensable item is the loading crane, although drivers and their trucks often work in pairs and the crane on one truck is used to load the other. In this case the crane would be mounted at the rear of the trailer, otherwise the preferred position is at the front. Where drawbar rigs are used the crane is positioned at the rear of the prime mover so it can service both truck and trailer.
The operator needs to be high up to work efficiently and to achieve this the seat, complete with controls, is mounted high on a pillar. Loading has to be done regardless of the weather, and protection for the operator is available in the form of a fully enclosed cabin complete with a diesel burning heater. In this case the whole cabin can be elevated hydraulically by up to a metre to improve visibility
As with all loading cranes, perfor
mance is measured in terms of load lir (tonne) and reach (metre). Not surp ingjy, the greater the tonne/metre capa ity the greater the cost. Swedish comp Jonsered and Finnish company Lo (handled in the UK by Outreach) b make a wide range of timber hand cranes with capacities up to 33tm.
The cranes are equipped with si cialised timber grapples which are cl eriy shaped to collect and grasp the lo Again they come in a range of designs handling maximum loads from three nine tonnes. To make loading easier grapple heads are rotated hydraulic Safety is paramount in timl haulage, and anyone using a loader m be properly trained and hold a certific of competence. Wet timber can be heavier than normal, and to avoid ov loading the cranes can be equipped v a Weigh-Link device that automatic tots up the individual loads as they . lifted onto the truck.
Timber haulage is a specialised op ation and good vehicles and equipm are essential, making it a very cap intensive business. It also calls for abi average skill and dedication on the p of those involved. The job can be a to one but no one ever said that haul; was an easy way to make a living!