56-40-40

The advantage of working as an owner-driver in a group is that contract productivity can be made up by the group if one vehicle is down.

It's not so long ago that trucks operated on SA roads at 40t gross combination mass (GCM) using fuel at 40l /100km," observes Freightliner's Eddie Caromba. And in the ADE era large normally aspirated V-engines -especially the 18,85-litre V10 model 443N -may have been perceived as reliable but were horrendously thirsty at around 50t GCM and 65l /100km. GCM started to increase with over-designed, heavy inter-interlink trailers making limited payload gains for 56t plus 5% GCM - 58,8t GCM was the benchmark of the past as everyone 'assumed' 5% was a law-book benchmark which it has never been. Fuel consumption is very route, GVM/GCM, driveline configuration and frontal area dependent - just to name a few key factors - but achieving 50l /100km at 56t GCM is considered good going. Now Barloworld Logistics, operating Freightliners at 56t GCM, are achieving 40l /100km hauling cement around Limpopo Province. Even better the tare masses are so low that these rigs are carrying 40t payload - now that's an astounding benchmark! It's a best-yet-ever productivity factor - 56-40-40.

56-40-40 is a collaborative result. It's where the user, truck supplier, trailer manufacturer servicing dealer, owner-driver management scheme and driver training have all come together in getting this remarkable achievement rolling out of Pretoria Portland Cement's (PPC) Dwaalboom cement factory situated 70km west of Thabazimbi. Driver training has been an imperative component of the project, not only in the area of familiarity with the Argosy and road safety, but in improved driving styles resulting in greater fuel saving. Freightliner's driver training specialist, Naveen Sook, makes frequent visits to Dwaalboom to train the fleet of owner-drivers.

PPC Cement's Batsweledi expansion project is bringing economic benefit far beyond the towns surrounding the company's Dwaalboom facility. The most recent beneficiaries of the R1.36-billion expansion project are 44 owner-drivers, appointed by Barloworld Logistics Africa to provide transport services to PPC. As part of a five year agreement between PPC Cement and Barloworld Logistics Africa a total of 340 000 tons of cement per annum will be transported by the owner-drivers.


A trucking weigh-less programme
So many new trucks are operating with excessively-heavy, old trailers that they miss productivity gains of new trailer technologies that are much lighter because they are designed to operate at legal loads. Previous designs always catered for a massive overload. In the 56-40-40 formula everything possible has been done to reduce tare masses.

The Freightliner Argosy power-plant is a CAT C12, an engine that is lighter than many comparable units for a 440hp output. The press blurb claims that at 'only 940 kg, the C-12 offers the best power-to-weight ratio of any engine in its class. In comparison to other diesel engines in this horsepower range, the C-12 offers nearly 272 kg of additional payload.' It doesn't stop there. Fuel tank size is limited to a single tank 450 l and tailored for the correct fuel capacity to the envisaged route distances - another 500kg saving if the tank mass is taken into account. 

A heavy bull-bar that would normally weigh 150kg has been replaced by an electronic 'DeerBuster' that weighs approximately 150 grams. Even the wheel nuts that fasten aluminium rims to the Argosy hubs have been selected for lowest mass - the multiplying effect of less grams per nut turns into kg removed from the whole truck.

The Afrit trailer interlink-combination was a design-project managed with inputs from Barloworld Logistics and Freightliner - the goal: be able to carry 41t payload without exceeding a 56 000kg GCM. Excluding tarpaulins, the complete interlink combination tare is only 6560kg. Trailer weight savings were achieved in 3 key areas - chassis, deck and running gear being axles, suspension, tyres and rims.

• Chassis: The bulk of the chassis is constructed from Domex high-tensile steel. Unnecessary bracketing was minimised and the main beams were designed to balance between being as light as possible and carrying as much as possible. Finite element analysis (FEA) was done to ensure longevity and durability.

• Deck: The deck is constructed of extruded aluminium panels. The panels are self -supporting, removing the need for conventional steel cross members . The deck on the rear trailer is split into two sections, due to the grouping of the load in two stacks at the front and rear of the trailer. The front trailer's deck is only 5,3m in length due to the length of the stack. 

• Running gear: Super single tyres and aluminium wheel rims were fitted to BPW axles. The aim is to get the weight distribution right and not exceed the 16 000 kg mass limit per axle group for super-single tyres compared to 18 000 kg for duals. Afrit opted for parabolic spring blades for the suspension, which provides benefits in the form of weight saving as well as the 'soft ride' it offers when the trailer returns empty over uneven roads.

And here's a flexible, clever thought for the future. Trailer chassis design allows for both 6m and 12m retrofit deck installation, should the trailers need to be used on another contract calling for maximum deck lengths. In this case, the axles are also prepared to accommodate dual tyre fitment if required.
 

Trucking’s Mr Weighless - While the 56-40-40 result is a team effort, Eddie Caromba played a major role in reducing the biggest mass factor– the Freightliner truck tractor.

Shed horsepower - save fuel
Revs mean kW and fuel consumption. Mark Clarkson, 'Technical Support' man for 'On-Highway Trucking' at Barloworld Power Systems explains a few of the application specific adjustments made to the CAT C12 engine - "The sooner a driver can get into top gear the better, so we've encouraged progressive shifting by limiting rpm in the lower gears. Our tests have also proved that this operation does not need max horsepower." The test results clearly show a saving of around 5 l /100km operating at 410hp in comparison to 430hp. According to Mark Clarkson torque of only 100Nm is lost in reducing power from 430 to 410hp.

The first test was done using the demo truck rated at 410hp, the second test was done using fleet number 038 which is rated at 430hp. Mr P Baloi was the driver on both trips. The trips were done on the same route which was from Dwaalboom to Lephalale loaded and then back to Dwaalboom unladen. The loss of horsepower only has a minimal effect on average speed.
 

Conclusion
A 1st world road transport achievement is happening in the Limpopo Province bushveld. This is the cutting edge of vehicle productivity and design that is both professionally driven and supported. At 56-40-40 the Barlow Logistics owner drivers are achieving better fuel consumption to GCM ratios than professional drivers in Europe - who says we cannot do it?

The team that has created this result deserves a round of applause.