Boxing clever 03 October 2014

Getting trailer specifications right is all about focusing on the operation and building on experience. But optimising them for efficiency and lifecycle costs requires a fresh look at available technology, suggests Brian Tinham

Anyone having more than a passing familiarity with semi-trailers knows that specifying the right vehicle for the job starts with understanding what it's for. New technologies might play a part in the final choice, but they're virtually never among upfront considerations, no matter how apparently compelling. Quite simply, to experienced eyes, the detail of the haulage operation dictates so much about what works well and what doesn't.

The danger, however, is that taking this approach can miss novel solutions that could make a significant difference. So there's much to be said for standing on the shoulders of metaphorical giants such as TIP Trailer Services, which trade on their ability to get trailers right for customers – technically, operationally and financially. Yes, it's a rental operation, so unlikely to push the boundaries too far, but – with a fleet of 8,000 plus 7,000 under operational and maintenance support – there are valuable lessons in its processes.

European marketing director Karl Davies states that getting trailers right is about combining experience with constantly refreshed market knowledge, in its case backed by an impressive engineering database covering fleets past and present. Staying close to OEMs and component suppliers is part of that. That way, he says, TIP is ready to take advantage of engineering and design innovations capable of impacting operations, but also, critically, cutting costs.

"It's not just about having trailers on our fleet that are all things to all men: we also need to engineer solutions for customers, and that means being aware of technical developments," explains Davies. "For example, we recently delivered a large number of box vans to a blue chip on a rental contract with a specification based on what they needed to service their customer. They were going to be heavy on floor usage in particular, so, drawing on our market relationships, we were quickly able to engineer appropriate trailers and put together the warranties, etc."

What does he value most? Davies is coy about specifics, but confirms that aerodynamics have proven themselves, with significant fuel-saving advances in recent years – although the premiums charged by suppliers mean that general box van and curtainsider rental customers "are not banging on the door for them". That said, he points to corner cappings and curved profile reefer front ends, designed to smooth the airflow over the trailer roof, as more prevalent. And TIP's latest £19 million 900-trailers order includes some teardrop style trailers, too.

Beyond that, he points to telematics – in TIP's case the Trailermatics system developed under its joint venture with Novacom Europe. "We're fitting the hardware at the OE stage and switching it on as required by increasing numbers of customers." And he notes that full EBS (electronic braking systems) is also now standard fare. "In the UK, we specify Haldex. But we also watch others and this year we're taking some systems from Wabco. In Europe, we also use Knorr-Bremse. Some of the new functions on all these systems have fantastic potential, but, for rental, the numbers have to make sense."

Back on aerodynamics, one company putting considerable effort into optimising its offerings is Cartwright. Its latest Fastback development came out of academic research with Manchester Metropolitan University and a Knowledge Transfer Partnership project last year. Cartwright R&D manager Andrew Bukowski says the goal was to develop designs that could be proven to deliver the best results most consistently across real operational conditions.

"Almost all aerodynamic modifications provide a benefit in all conditions – but some more than others," states Bukowski. "So finding the right combination was the issue, and then tailoring that for specific operators. For example, side skirts offer much greater benefits in cross winds than head winds, so, because of the prevailing winds in the UK, operators running predominantly north-south are likely to see greater benefits than those travelling east-west."

That's why Fastback (which builds on Cartwright's earlier Cheetah) has full side skirts, a curved bulkhead and curved cant rail, but a roofline that slopes only at the rear. "The design has a sloped chassis to retain the full rear aperture, but the point is it doesn't raise the side profile and risk reduced benefits in side wind conditions."

Bukowski reckons the full package is capable of delivering around 12% fuel savings, depending on the operation. That may sound low, given its sophistication and scale, but savings from individual aerodynamic interventions are rarely additive, because of the potential for interactions. He also warns that fuel savings can easily be undone simply by running mismatched tractor cabs. "Even a 20mm mismatch can see 3% wiped off. And a cab normally matched for a 4.2 metre trailer swapped to a 4.88 metre flat-front double-deck can result in a 25% fuel performance penalty that could easily have been mitigated by fitting a deflector to the front of the trailer."

Looking to the future, he points to the introduction of boat tails as the next big aerodynamic intervention. For him, though, there are two issues. One concerns the current maximum dimension of 500mm on the trailer rear, which limits the benefit. The other is just how quickly European freight firms will be able to implement them into operations, given the difficulties – particularly with depot infrastructure and staff training – experienced to date in the more advanced US.

"The larger the boat tail, the larger the fuel savings, but also the greater the risks, in terms of accidents and maintenance," he observes. So draft legislation, due late 2014 or early 2015 (modified Directive 96 53 EC), allowing longer fins could turn out to present a double-edged sword. "The legislation will control designs to make them as safe as possible, in terms of rear impacts, etc, but boat tails will have to be operated correctly, folded back at dock doors, etc. It will be interesting to see how UK operators get on with them."

That said, Bukowski claims that Cartwright is ready, having done its homework and developed optimal angles, positioning and materials. "Some trailer types will accommodate them well, but others will struggle. For us, early adoption will probably be on a per-trailer basis while we perfect the mechanisms."

Wabco sales manager Andy Chapman says his company is similarly prepared. "We're close to launching a collapsible tail fin as part of our aerodynamics range," he says, indicating that availability will be early in 2015, although not for curtainsiders. However, he agrees that, for, now side wings offer the biggest bang for operators' bucks – pointing to the firm's OptiFlow system, developed following Wabco's acquisition of Dutch specialist Ephicas.
He concedes that they're not for everyone, suggesting that box vans, refrigerated vehicles and some curtainsiders are most likely to benefit – although the concern for the latter is damage caused by forklift trucks. "They are ideal for one-, two- and three-axle semi-trailers and rear steers, as long as the operation involves at least 60% motorway or highway driving at 70kph. We've seen as much as 1.6 litres fuel saving per 100km."

The devil, however is in the detail, says Chapman, suggesting, for example, that operators avoid wraparound rear skirts, which can cause drag, but also highlighting OptiFlow's patented flow conductor on the inside leading edge – claimed to improve airflow down the trailer underside. "We also believe very strongly in enclosing the wheels. Ephicas' wind tunnel tests proved the benefit, compared to open wheels. And there are no issues, in terms of maintenance and drivers' walk-around checks – the flaps simply lift up and off for inspection."

That leads us neatly on to trailer running gear. And, while there have been few mechanical advances – aside from those developed at CVDC (Cambridge Vehicle Dynamics Consortium), with its fast electronic braking valve and computer-controlled rear steer systems – electronics are now capable of significant improving trailer operations. Wabco is a case in point, with its latest EBS options also enabling better manoeuvring, increased fuel savings, axle overload prevention, brake safety interlocks and even safer tipping operations.

Chapman cites the EBS's ability to lift trailer axles, where fitted, more accurately than with conventional systems. "The system can lift and drop them automatically, according to detected load, both to save fuel in normal running and to effectively reduce the wheelbase for manoeuvres. And it can assist with traction by lifting axles to temporarily impose more load on the tractor kingpin. But, just as important, where lifting axles aren't fitted, our EBS can dump air out of the rear axle suspension, which again reduces the turning circle radius by half a metre and saves on tyre scrub."

The latter is impressive: you get some of the functionality of a steered axle, without the on-cost, weight or maintenance issues. Chapman explains that it's controlled automatically – on the one hand detecting kerbs, but on the other triggering on tight corners by sensing the wheel speed delta side to side. It can also be a switched function for driver, although the facility automatically turns off above 30kph.

As for the rest, axle overloading can be automatically prevented by pressure sensor inputs to the EBS. "Morrisons has about 50 trailers with that system and Shcmitz Cargopbull is now offering it under their own brand," says Chapman. And he points to Wabco's OptiLoad, which extends that functionality to deal with the problem of multi-drop trailers experiencing axle overloads (more common in mainland Europe, which favours 4x2 tractors) by again controlling axle airbag pressures.

And it's a similar story with: rear steer on-off control (with EBS using speed data to enable-disable accordingly); safety interlocks (for example, applying foundation brakes when tanker pump locker doors are open); and tipping trailer safety management (EBS warns the driver and/or disables tipper gear, using inclinometer data for its roll stability program).

Incidentally, Wabco also offers OptiLevel trailer levelling technology, based on its eTASC electronic trailer air suspension controls.That enables everything from programmable lift-lower, for trailer docking, to automatic height compensation during loading, and ride height management, which the firm claims saves fuel by eliminating constant air bag pressure adjustments, common with levelling valves. And it's worth checking out its TrailerGuard and TailGuard systems. The former provides remote telematics coverage of brake pad wear, tyre pressures, coupling integrity, door sensor and EBS itself. The latter is about sensing small and moving objects behind the trailer to assist with reversing.
Chapman says TrailerGuard is already being used by Turners of Soham, while among big users of TailGuard is Martin Brower, which handles transport for MacDonalds. "TailGuard has been specified on all their [Montracon and Grey & Adams] trailers for the last two years," he confirms.

We've covered a lot of ground but before closing spare a thought for some additional safety measures, light-weighting opportunities and simple choices that can cut costs. For the first, it's interesting to note Sainsbury's latest developments (initially on rigids), in terms of roof-mounted 360 degree, birds' eye view camera systems, ultrasonic side sensors and puddle lights. It's all about protecting vulnerable road users – and trailers go into urban and city environments too. As Sainsbury's fleet manager Gary King says: "We will put all the technology from our rigids into semi-trailers."

On light-weighting, the focus has largely moved beyond running gear and trailer chassis, which are now mostly at the stage of diminishing returns. So it's worth revisiting trailer body constructions. Andy Richardson, engineering director at Lawrence David, advises that plastic and sandwich panels, with solid, foam or honeycomb cores, have moved on from the old days. Durability is good; they don't saturate with condensation and water ingress over time; and there's a significant capacity as well as weight improvement. "They may cost more, but they also last longer and look better," he asserts.

And finally, for cost cutting, just remember the opportunities with tyres. Richardson suggests low rolling resistance for fuel saving, but also mini-singles for low deck height applications. "You get more stability and better wear characteristics – almost double the life of conventional twins."

TJ Hammond's choices
Transport operator TJ Hammond has taken delivery of a 13.6m, multiple-access box van which, according to the firm's Nick Curson, will boost utilisation, flexible loading and security. The Ekeri semi-trailer features a sophisticated door system, with central locking, allowing the load bed to be accessed along the length of the trailer on both sides and through the rear barn doors.

Canute Group's choices
Distribution and logistics specialist Canute Group says it has solved access problems at loading bays for a high street retailer by specifying Tridec steering systems on 13.7 metre semi-trailers. Glenn Marshall, engineering director, explains that previously, the operator had to use smaller trailers, leading to high frequency deliveries and obvious inefficiencies. "I've worked in the industry for a long time, but I've never seen a trailer configured in this way," comments Marshall. "We have found that it gives a 45 foot trailer a similar turning circle to a 30 foot trailer."

Author
Brian Tinham

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