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Rear steers pay dividends
Page 16
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by John Kendall • Access to farm sites is the bane of many an agricultural haulier. Artics present just about every problem there is, from height, width and length, to swing clearance and ground damage. It's enough to ensure that many farm sites do not welcome them through their gates. For the agricultural haulier this restricts the size of load that can be collected or delivered which, for regular supplies such as animal feed, may mean laying on extra deliveries.
Rear-steer trailers offer a possible solution to many of the artic related problems because of their increased manoeuvrability and potential for reduced ground damage down on the farm. They also offer the possibility of getting 38-tonners into more sites, cutting down on the number of visits needed by a This was the thinking behind Dalgety Agriculture's decision to trial rear-steer trailers in East Anglia. The company based the trial at its Wals,ingham site in North Norfolk which distributes bulk animal feeds. The small fleet based here used to consist of seven Volvo FL10 8x4 chassis and one 6x4 with bulk bodies and three artic combinations.
The trial began just over a year ago: apart from a single eight-legger the entire fleet was replaced with rear-steer artics. Dalgety chose the Volvo FL10 320 6x2 tractor with midlift axle, coupled to a Bridge Bodies tandem-axle tipping bulk-feed trailer running on wide-single tyres. The trailer's rear-steering gear was supplied by Tri Dec in the Netherlands.
The first advantage was payload. The artics can haul 22 tonnes—four more than a 30tonne 8x4. Dalgety can carry four different loads in the fourcompartment trailers and all the bulkheads can be moved to cater for differing load sizes in each compartment. The Dresser Holmes hydraulic drive blowers are driven off the FL10s' To ensure that customers get what they pay for and are billed for the right amount as well as keeping the vehicles legal—all trailers are fitted with PM On Board weighing equipment.
Trucks and trailers are on contract hire; the trucks from Volvo Truck Finance and the trailers from TIP. Maintenance is handled by Norwich Volvo distributor Duffields.
So what are the operating advantages over the 8x4? According to Dalgety's Philip Gladwell, a l5% improvement in efficiency for a start, which is mostly due to the higher payload. Downtime has also been reduced. Duffields carries out servicing overnight and annual testing at weekends.
The combination of lift-axle tractors and steering trailers mean that ground damage on customers' sites can be minimised. As soon as a truck is off the public highway the tractor mid-axle can be lifted to reduce tyre scrub and ground damage when manoeuvring. The new artics are certainly causing less ground damage than the lighter 8x4s: for farmers who were previously not keen to have artics on their land, this is now a forgotten issue.
A brief drive around the narrow Norfolk A-roads shows how easy the combination is to drive. The trailer does not cut in on corners and behaves more like a drawbar combination. Negotiating narrow junctions means that less road space is needed to get round, so the rearsteer system has benefits onroad as well as off.
The steering mechanism is controlled by a fitting in the back of the fifth-wheel jaws. The lower part is fixed but the top half moves with the trailer as the vehicle is steered. This is attached to a linkage which runs the length of the trailer to the rear turntable and steers the back axle.
Bridge Bodies builds the entire trailer in-house: only the painting is contracted out. The company has supplied more than 20 rear-steer trailers to Dalgety, proving the success of the Walsingham pilot project.
Dalgety also runs a dozen 8x4s from Bury St Edmunds, and Gladwell plans to replace at least half of these with rearsteer attics.