Mack Super-Liner and Elphinstone long logger: Operator Review

Roughly three hours’ drive north of Brisbane, hidden within the verdant embrace of Tuan State Forest, lies a bustling hub of Queensland's timber industry where the rhythmic hum of progress harmonises with the whispers of towering pines. 

As dawn bathes the forest in golden light, the symphony of day-shift activity begins as night-shift ends. Mighty Mack Super-Liners, towing the iconic Elphinstone long logger trailers, rumble along neatly graded gravel roads on their daily pilgrimage to transport tall timbers to the sawmill. 

Each truck, a testament to Australian engineering prowess, is not merely a vehicle but a symbol of reliability and endurance, meticulously crafted to conquer rugged terrain with unparalleled grace. 

What sets this operation apart, however, is the marvel of modern ingenuity – the Elphinstone long logger trailers. These behemoths of timber transport are more than mere carriers: they are architects of efficiency, designed to cradle vast loads of sustainable plantation timber with unwavering stability. Forging a formidable partnership as they join forces with the Mack Super-Liners.  

The Sunchip Group is a harvesting and haulage contractor based in the Fraser Coast region in Queensland. 

“They’ve been operating here for the last 26 years, and for most of that time, have been using Mack trucks and Elphinstone logging equipment. Today, we run about 15 of their units with another 10 on order,” said Michael Whish-Wilson, Transport Supervisor Tuan and Toolara Forests. 

“We predominantly use long logger trailers working around the clock for five days a week."

Mark Blackberry, owner and founder of the Sunchip group, worked with Graeme Elphinstone to develop the trailers. 

“These unique trailers allow us to cart up to 1.5 million tons of sustainable plantation pine annually," he said.

"The long logger trailers permit us to do such high volumes because they allow us to safely cart long lengths up to 18.3 meters on the B-double route and archive a 45-tonne payload with fast loading and unloading times.

"That's why we specked it up with the 685hp MP10 and specified the mDrive with the HD shift option. When you throw a 45-tonne load or logs on the back, it needs plenty of power to climb the hills around here." 

The MP10 under the hood is an in-line six-cylinder displacing 16.1 litres and specked with a stump-bustin' 685hp (515 kW) and 3150Nm (2300lb/ft). Mack's MP10 uses an SCR (selective catalytic reduction) emissions control system and because of its phenomenal torque output, the 685hp rating is only available with Mack's mDrive 12-speed automated transmission. 

The Super-Liner boasts a massive radiator with a sprawling frontal area of more than 11,290 square centimetres, designed to cope with the high cooling requirements of heavy haulage, road trains and of course logging operations.? 

The Mack MP10 engine uses an electronically activated Behr viscous fan clutch, which, apart from being almost unnoticeable in operation,?works according to actual cooling needs by delivering anywhere from five to 95 per cent of fan engagement. Put simply, rather than being totally on or totally off, the fan responds with incremental engagement, depending on the required cooling assistance. 

The MP10 also boasts a surprisingly effective engine retarder called?'PowerLeash', dispensing up to 570hp (425kW) of engine braking effect at 2200rpm. Mind you, it's not in the same class as the engine brake performance of a 15-litre Cummins, but by manually shifting down a gear or two to keep revs up, it's an engine brake capable of delivering effective retardation even at weights beyond 70 tonnes. 

Mack engineers spent several years researching, developing, and testing a beefed-up version of the mDrive before releasing the HD option for on- and off-road duty. Back at the launch, Mack explained the HD option has tougher gears and synchronised than the on-highway mDrive released in 2010 (which, incidentally, more than half of all customers for highway Macks now choose). Conversely, the HD model also has a more efficient oil cooler and uses higher-viscosity synthetic lube oil. The 12-speed mDrive HD is rated for up to 2793Nm (2060lb/ft) input. 

Weight and price are usually critical factors in the heavy truck purchase decision-making process, and the mDrive is among the lightest transmissions on the market. Surprisingly, Mack's single-countershaft mDrive weighs about the same as a comparable Eaton 18-speed manual transmission with twin countershafts and far less than the heavy-duty triple-countershaft Mack manual.? 

Michael says the mDrive always selects the correct gear irrespective of how fast or slow he drives or whether he is on undulating or flat terrain. 

There are three operating modes – Easy Shift, Enhanced Construction and Heavy Haul – with the Sunchip Macks using the latter so shift points are a little higher on the tachometer. Moreover, technicians can program the settings at Mack's service department to suit customer needs. 

The dash-mounted gear selector includes a "Perf" (for performance) button, which delays upshifts and adds power and torque as engine revs rise, making the truck noticeably livelier during acceleration.? 

Michael explained this feature was especially effective as the transmission changed into the higher gears and the road speed climbed – after which another touch of the "Perf" button returns the transmission to economy mode. 

"The long logger trailer is essentially a hybrid between a skel trailer and a jinka," Michael explained. 

“The skel trailer is up front, and the stinger-steered jinker is connected to the rear of the front trailer. The trailer folds and unfolds automatically; there's virtually no manual input from the drivers, and they can do almost all of it from the comfort of the cab. They're very user-friendly, and best of all, you know they work day-in and day-out. 

"The original long logger trailers we started running in 2008 had a lifespan of about 15 years and covered millions and millions of kilometres. To put that into perspective, we replace prime movers every four to five years and merely connect the new trucks to the older trailers. 

“I think each of those original trailers carted well over a million tonnes per unit over their lifespan. Mind you, we have a comprehensive maintenance program to ensure all our equipment gets maintained in first-class condition. 

"One important thing to mention about these trailers is that we use Elphinstone's Easy-Weigh Multi reader in the cabin connected to loadcells on the trailer to weigh each load accurately. Our overload percentages are virtually zero; a terrific result given that we're doing 100 plus B-double loads of timber a day and go months and months without a single overload. In an environment with so many variables, still having such reliability out of the scales is just unreal. 

"The investment in accurate onboard scales certainly pays big dividends in the long run. For example, if we underload each truck by as little as 1.5 tonnes per load, that means we're losing over 150 tonnes of productivity per day. That's 750 tonnes per week, which is the equivalent of about 16 extra loads we'd need to do to bring that same amount of wood. I can't emphasise the importance of Elphinstone's accurate onboard scales enough.” 

Truck Specs: 

Model: Mack Super-Liner 
Engine: Mack MP10 16-Litre  
Horsepower: 685hp (515kW) at 1800rpm 
Torque: 2300lb/ft (3150Nm) at 1000-1400rpm 
Gearbox: Mack TmD12A023 mDrive 12-speed Overdrive 
Retarder: Mack PowerLeash 
Front Axle: Mack FXL 16.5 unitised hubs 
Front Suspension: 1397mm Parabolic 7500kg with anti-roll bar 
Rear Axles: Meritor RT46160GP with diff locks to both axles. 
Rear Axle Ratio: 3.73 
Rear Suspension: Mack AP460 21 Tonne 
Brakes: S-cam with ABS 
Safety: EBS with integrated ABS and traction control 
Interior: Pleated Ultra Leather (Burgundy) 
Seats: ISRI Premium 'Big Boy' Driver's Seat 
Bumper: Polished Alloy  
Fuel Tanks: 1x 500, 1x 200 LHS and 1x 350 total volume 1050 litres 
AdBlue Tank: 1 x 150 litres  
Batteries: 4 x 12 volt  

Trailer Specs:  

Axles: BPW ECO Plus  
Suspension: BPW Air 
Chain box: Checker plate with step 
Load restraint: Manual winches 5000kg 
Remote release: Yes 
Cab guard: Yes 
Loadcells: Yes