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Prime Mover Magazine


Scania R 730

Scania R 730

With 730hp available on tap, Tim Giles takes the new top power Scania through the Northern Territory and Queensland to see how the truck performs at a heavy tonnage.

When the Scania R 730 was released, the headline figure, in reality, was not the 730hp (544 kW) but the more impressive 3500Nm (2581 ft lb) of torque available to the driver. The horsepower is the thing that keeps the truck and its load at high speed but it is the torque which gets the truck up to speed and drags the vehicle mass uphill on a grade. The badge on the front of the truck says 730hp but its torque rating doesn’t get a mention. However, those in the know are well aware that it is the high torque figure that should impress.

Taking a B-triple from Alice Springs in the Northern Territory to Longreach in Queensland is an opportunity to test the mettle of the engine output from the all new V8 engine from Scania. Loaded to 77 tonnes, the combination could travel in its natural element, in a situation where plenty of power and plenty of torque can really make a difference. Prime Mover joined the convoy over a period of two days to see just how much difference an extra 300Nm can make.

In reality, most of the R 730 trucks sold by Scania around the globe will not be expected to handle the rigours of multiple combinations in outback Australia. Many will be sold in Europe where the 730 badge will be seen as a method of recruiting drivers and retaining their services. Although trucks in Europe can run up to 60 tonnes, most prime movers pull single trailers and rarely go over 40 tonnes and 90km/h.

The engineering achievement of creating a V8 engine that can put out this much power and torque is matched by a driveline which has been engineered to handle this kind of turning force and retain the kind of durability required by trucking operators. Truck manufacturers are now living in the over 700hp era, something we have never seen before – the horsepower race is on.

It is clear as soon as the truck sets off that the driveline appears to be doing it easy. Normally, when taking off with a combination at this kind of weight, it is simply a matter of waiting while the speed and rpm levels slowly rise before taking the next gear. Acceleration is normally steady and it’s important to make sure you’ve got a completely clear road before pulling out on the highway.

From the driver’s point of view, taking off with a B-triple with this kind of power feels like the kind of acceleration you would expect from a top power prime mover pulling away with a B-double. And from the driveline there is a kind of effortless feel from the driver’s seat. All of the evidence points to something working very, very hard as the truck pulls away, but the feeling in the driver’s seat is that it’s not working too hard at all. The sound levels in the cabin from the engine are very low, as are the rpm levels. There is no vibration from the driveline, it all seems to be going very smoothly but, at the same time, a 77 tonne combination is accelerating down the highway.

In most situations out on the road it is this sensation of effortlessness that recurs over and over. As a driver, you are insulated and isolated from what is clearly a lot of hard work being done by the driveline and the other vehicle systems, like the retarder. Sometimes it is almost too quiet. It is possible to forget just how heavy this combination is and lose sight of the responsibility that comes with heading down a highway at 100km/h with 77 tonnes up.

For many of those working in this sort of area and at these sort of weights, the environment for the driver of the Scania R 730 would be quite alien. Most trucks in this kind of work are North American, with punchy North American drivelines and a manual 18 speed Roadranger. High noise levels are part of the package, drivers like to hear their Cummins, Detroit or Caterpillar clearly. When the engine brake comes in, noise levels go up again, it’s part of the job.

One aspect of this experience with US trucks is the fact the driver is never going to feel isolated in any way from the work rate of the prime mover with the kind of mass they are hauling along the highway. The prime mover and trailers are giving constant feedback, forcing multiple gearchanges and forcing the driver to keep an eye on all of the instruments as the truck heads down the highway.

The driving experience in the Scania is so completely different. If there is anything amiss in the truck’s systems then the information screen directly in front of the driver will put up an alert. The driver’s job is simply to keep the combination on the straight and narrow without letting the rear trailer skip about too much.

On this test drive there was an incident that the driver information screen could not help with. One of the tyres on the rear axle of the rear trailer decided to let go. Luckily, the following truck noticed the new rubber on the road and could call ahead to the B-triple and get it to pull over before too much damage was done. These are the kinds of things that happen on these types of roads and there is very little the driver or operator can do to help.

Much of the driving on this test drive was in relatively flat country where the torque can demonstrate its prowess as the truck is accelerating away from a stop or after slowing down for an obstacle. Once up to highway speed it is the turn of the power levels to show just what they are made of.

This truck was able to hold 100km an hour more successfully than other trucks around it on the road. At a high mass like this the driver can expect any slight uphill grade to slow the truck considerably. In many cases, most of these grades did no more than wipe a couple of kilometres per hour off the speed and get the big V8 engine to dig in and maintain road speed.

However, the section of highway between Mount Isa and Cloncurry in western Queensland is a much different proposition. The series of climbs and descents on this stretch of road are a real test of a truck’s capability and of whether the driveline really has the capacity to handle hard and heavy work. This 120km stretch of the Barkly Highway travels through a number of hills and valleys which are part of the rugged countryside in this area of the west.

In this kind of situation, a driver’s first instinct will be to quickly flick the control over to manual and use their experience and knowledge of the conditions around the truck to make gearchanging and retardation decisions. On this test drive, however, we decided to see how well the automated systems Scania has developed can handle, what can only be described as, some pretty tough driving at 77 tonnes.

It was possible to travel the entire distance using just a couple of the controls on the steering wheel to control everything the truck was doing and to maintain a high average road speed for the entire trip. With the transmission set to automated and the cruise control at 100km/h, the driveline was more than willing to take on these grades and show just what it can do in these conditions.

At the foot of the grade, the truck would often sense the increase in the incline and quickly opt for a lower gear and higher rpm. This is exactly how the driver would react as the truck gets into the meat of the climb. The gearchanges are swift enough to ensure there is a minimal loss of momentum as the truck attacks the climb. For the driver it can be a little unnerving as the rpm levels appear to be allowed to drop quite low, but there is always enough torque to keep the B-triple going well.

Just before the crest of the rise it’s time for the driver to start thinking about going down the grade. Using the momentum of the truck to carry it up and over the top of the grade, the driver engages the automatic downhill retardation control using a button, very similar to the cruise control, also placed on the steering wheel. The system is then primed to try and hold road speed down to the set level using the retardation system.

By pressing the plus or minus buttons, it is possible for the driver to modulate the speed of the truck down the grade. With 77 tonnes pushing the combination downhill, nine times out of ten it was a matter of pressing the minus button to try and hold the truck back to a safe downhill speed. On a couple of occasions, due to increased incline on the downhill grade or slower vehicles on the road, it was necessary for the driver to intervene and actually touch the brake pedal to wash off more speed and keep well within the safety margins.

Once the truck gets to the foot of the grade and the trailers are no longer pushing the truck downhill, it is simply a matter of hitting the resume button for the cruise control and allowing the system to take over again and keep the truck as close to 100km/h as it can. The driver has climbed and descended a serious hill hauling serious mass and controlled it with just a few touches of a couple of buttons and the occasional light braking application.

Driving a truck like this can be quite unnerving for a driver used to controlling all of those systems individually. It is necessary to build up an element of trust between the driver and these sophisticated speed control systems. Once that trust has been built up, it can allow the truck to do most of the work and simply monitor the situation. This kind of driving can be much more relaxed as a result of not having to constantly change gears, press the accelerator, clutch, touch the brakes and turn engine brakes etc on and off.

Although the driving style is more relaxed when handling a truck like this, it is still vital to remain very alert, at all times. There is no getting away from the facts and three trailers with a gross combination mass of 77 tonnes travelling at highway speed is constantly at risk – driver vigilance is paramount. Hopefully driving the truck this way reduces fatigue and enables the driver to remain more fully alert for longer.

This combination of technologies, both from the driveline point of view and from the electronic control systems, modulating the accelerator and retarder controls, does work well in these long-distance outback driving situations. A truck designed mainly to suit the prejudices and proclivities of the European truck operator also has the capability to do a good job for Australian truckies handling heavy loads over long distances.

Some of the limitations imposed on the trucking industry in Europe also affect this truck’s usefulness to the industry here in Australia. The strict limitation of semi trailer length to 16.5m does mean the cabin itself does have less room inside than would often be to the taste of drivers working in this part of the country. Scania has managed to pack in quite a lot of the necessities of life for a truck driver into a relatively small package. The under bunk fridge and freezer work well and are easy to access.

Storage around the cab is practical and there is generally enough room for all those things that the long-distance truck driver chooses to bring along with them on the journey.

This is not a large American-style cab where the driver can stand up and walk backwards towards a large bunk with a large amount of cupboard space behind the seats. Scania has worked hard to alleviate the problem, the roll-out bunk is certainly big enough for Australian truck driver tastes. When the bunk is rolled back and the seats are put back into their driving position, the cab is user-friendly and easy to move around in. It is simply a matter that rolling out the bunk limits access in and out of the cab and it can be a little awkward for the driver, at times.

Overall, when evaluating the R 730, test driving a truck like this in these conditions is simply a matter of ascertaining whether it really can do the job and whether it can bring something new to the table. On that score it is possible to say 730hp and 3500Nm is certainly more than enough to handle this kind of work with ease. From the driver’s seat the truck appears to do the work effortlessly. Add in the sophisticated control systems available from Scania and you have a truck that can be driven long distances and at heavy masses while minimising the impact of fatigue on the driver.

If Scania does have a problem, it will be in convincing operators to move away from powerful North American trucks with large cabin interiors to the more sophisticated, but also smaller cabins from the Scandinavian truck manufacturer. It is also sometimes difficult to see how well this European truck style sits alongside the truck driving culture on the highway in the outback.

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