UK hauliers face a challenge when it comes to operating in tough winter conditions. Snowfall doesn’t occur often enough to justify spending big money, but when it does, blame is often pointed at operators as well as local authorities. So how do those in Scandinavia stay on the road? Transport News Brief met Scania’s driver training team in Norway to find out how it handles persistently low temperatures.
Veronica Andersson, test driver from Scania’s demo department in Södertälje, Sweden, says safe winter driving is mostly about good observation and planning. “There is more grip here than it appears, but you have to employ it intelligently,” she says.
After a cautious descent down a forest track to the main road, we set off in a 60-tonne, 24-metre fully loaded timber drawbar with an A-frame trailer and two turning moments. Travelling down an 8% gradient of 6km at 60kph was difficult enough, but negotiating a single carriageway with professional loggers coming the other way making good progress, required concentration.
The first mistake was to engage the retarder. Veronica pointed out that of the seven axles on the ground only two are affected by the retarder or any other auxiliary braking, so the remaining five, including the entire trailer, are receiving no braking effort at all. This can lead to a situation where the trailer is pushing the rigid, which can cause the driven axles to slide because too much is being asked of them. Simple but gentle use of the service brakes is more effective.
In recent years drivers have seen retarders, intarders and engine brakes drilled in, but it’s an element that needs to be re-calibrated when driving on mud and snow. Driving on compacted snow and ice does not need snow chains, except in the harshest conditions, although in the Trysil region of Norway it is a legal requirement to carry them and know how to use them.
Winter tyres provide better performance from +7º, and with very little grip underfoot, the benefits they delivered were surprising. The fully loaded timber drawbar relied on just two of its seven axles for traction, so a set of Continental HDR2 winter mud and snow 385/55 R22.5s, and a lot of weight helped keep us moving.
Turning off the highway where there was mostly visible tarmac and onto a forest track, we encountered compacted snow and ice, and an incline with bends. The drive axle tyres had a big job to do, but it was steady with no dramas.
Useful traction devices included a double-drive bogie, which does not offer the advantage of a lifting axle to aid traction, but the R520 6×4 had the next best thing. From the cab, it is possible to adjust the air pressure in the suspension bellows and re-apportion the weight on each of the drive axles. With the bogie rated at less than 20 tonnes, the pressures were adjusted to increase the load on the leading axle to 14.6 tonnes, guided by a dashboard display. This temporarily gained valuable traction to keep the wheels moving – it’s almost as good as a bogie lift, but on driven axles.
The demo trucks were fitted with automatic sand spreading boxes and the Norwegian manufacturer, Autoline, was there to explain. Mounted in front of a driving axle, a stainless steel box contains sand, or salt in the UK, with a heating element to prevent it freezing solid. A button in the cab dumps sand immediately in the path of a pair of tyres that are losing traction.
Finn-Ero Bustadmo, from Autoline, says theboxes are essential for winter operations in Scandinavia. Timing is everything, and if you have ground to a halt, it’s a moment too late – the button should be pressed as you feel the traction going.
“They can even help when approaching traffic lights on a gentle slope, with a glazed surface. It’s not all about the back woods,” says Finn-Ero. Shovelling sand under the wheels to give a stranded vehicle some extra bite is being wise after the event.
UK hauliers that operate in Scotland or the Peak District know that snow can stop the job, so what can they do to prepare for winter? If stranded vehicles are a regular occurrence, a salt spreading box is worth looking at. Also, investment in a winter driving training day will be money well spent, as injudicious use of the retarder that a driver has been told to use could cause a breakdown or worse. At the very least, winter tyres are essential for keeping Britain moving.