Hybrid hauler
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Is it a bird? Is it a plane? No it's Krone's Swap Trailer. This 18.65m drawbar/artic hybrid is creating a lot of interest with continental high-volume shippers. EU legislators notwithstanding, it could be just the answer for big-cube buyers.
What's the difference between an artic and a drawbar? Kid's stuff! An artic pulls a semi-trailer which is attached to the tractor by a fifth wheel. A drawbar is a rigid prime mover connected to a trailer via a drawbar coupling.
So what do you call an artic which pulls a drawbar trailer whose body is located by two fifth wheels? You call it the Swap Trailer from the German trailer maker Krone.
By cleverly exploiting European construction regulations Krone has come up with a trailer that can carry 38 Euro pallets within a voluminous 110m body with an uninterrupted 15.54m internal load platform length.
Quite a trick if you can do it. So how has Krone made all that space available?
At the heart of the Swap Trailer outfit is a tri-axle drawbar trailer linked to a conventional 3.6m-wheelbase Volvo PH12 tractor by a low-height drawbar coupling fitted to the tractor's rear cross-member, complete with all the usual air and electrical connections. On top of the trailer sits a 15.65m curtainsider swap body, attached to a conventional fifth wheel on the tractor and to another fifth-wheel mounted above the trailer bogie. However, both these couplings do little more than locate the body on the trailer. The actual weight of the box is supported by cross beams on the trailer and strengthened mud wings over the wheels.
According to Krone's export manager JOrg Sanders. the Swap Trailer rig allows an operator to carry the same volume as two high-volume 7.82m swap boxes while still using a normal tractor that can be coupled up to a conventional semi-trailer at any time. "This replaces some of the classic drawbar equipment," says Sanders.
Compared with a traditional drawbar the overall uninterrupted length of the Swap Trailer body gives about 1.8m more platform length which equates to four more pallets.
The longest semi-trailer you could normally achieve with an attic under C&U regs would be 13.6m. But because the Krone load carrier is classified as a drawbar trailer it can be that much bigger.
And following changes in European law to reduce the need for complicated adjustable short drawbar couplings on maximum volume outfits, swap-bodied drawbars can now run at up to 18.65m overall length with two 7.82m bodies.
What Krone has done is to effectively join those two swap bodies together to create an "artic-type drawbar" which meets the law for drawbar volumes but can still keep within artic turning circles (see diagram).
Quick-witted engineers will already be asking the question: "What happens when it goes round a corner?" After all, the box is connected by the two fifth wheels, so when the Swap Trailer outfit goes round a bend the distance between them will have to change, To compensate for the dimensional variation when cornering, the trailer fifthwheel sledge plate is mounted on a set of four rollers and moves up and down inside the chassis.
Using air-suspended SAF axles the body can be raised and lowered by up to 750nun allowing simple V-shaped landing legs to be pulled down and the swap body dismounted. While it may have a high volume and 2.7m internal height, the rig still comes in within the Continental 4.0m height limit, helped by a narrow 100min neck on the supporting swap-body frame and 305/55 R19.5 Continental tyres on the trailer bogie.
Not content with offering 110m-3Krone is looking at producing a Mega Cube version of its Swap Trailer that could provide as much as 130nr3 of bad space.
Regular CM readers may well remember a similar vehicle developed by the Dutch company Estepe (CM 19-25 March 1992). But unlike the Estepe outfit, the Krone vehicle combination has a normal tractor as its prime mover, thereby ensuring its flexibility in any fleet.
Krone's Swap Trailer has already created a lot of interest from companies such as BMW and Coca-Cola and among distribution managers keen to squeeze even more cargo on a single truck and lower their unit transport costs. Whether hauliers would get a better rate for buying a Swap Trailer remains to be seen.
Unfortunately there's one fly in the ointment—type approval. Right now the European authorities refuse to accept the Swap trailer. However, Krone says it will fight hard to get it through. Once one EU country grants type approval in theory it should be accepted by other European states—including the UK. Whether that will work out in practice is another matter.
Li by Brian Weatherley
SWAP TRAILER SPECS
Overall combination length: 18.65m. Prime mover: Volvo FI112.420 3.6m-wheelbase 4x2 tractor with rear drawbar coupling. 7131ie, Krone drawbar with three 9.0-tonne capacity SAF air-suspended axles fitted with 385/55 R19.5 Continental tyres. Trailer tare weight: 4.3 tonnes. Swap body: Krone curtainsider with Edscha sliding canopy system, located by twin fifth wheels. Body supported by trailer. Body tare weight_ 5.66 twines. Max gross weight: 30.0 tonnes. External length: 15.65m. Internal load platform length: 15.54n Internal width: 2.54m. Internal height: 2.1m. Capacity: ll0m3, equating to 38 Euro pallets. DRIVING IMPRESSIONS What's it like driving an 18.65m drawbar that thinks it's an artic? The answer is "surprisingly easy". Commercial Motor recently had the chance to drive an unladen Swap Trailer on the narrow rural roads dose to Krone's German factory.
Given the length of the outfit the natural reaction is to overcompensate on tight tums, especially to allow for the front and rear overhang. However, in practice the rig tracks amazingly well even round tight 90' turns in towns. From the driver's seat the front overhang appears little dftferent than that on a conventional 13.6m trailer.
What you do have to remember is the projection of the trailer's side guard on the outside of the turning circle, although it sticks out no further than the back wheels of the tractor. And as you turn, hope that some fool following in a car isn't going to try and slip past just as the back of the swap body is swinging out to meet him!
Moving out on to a long straight stretch of open road Krone's demonstration driver suggested we make a rapid see-sawing motion with the wheel—not the kind of thing we'd usually want to undertake with an unladen drawbar at 80km/h.
Somewhat reluctantly we obliged. The rig stayed rock steady with none of the worrying wig-wag movement that might be found on a drawbar after such a manoeuvre.
Next we tried backing the Swap Trailer into a side road. It may be a drawbar but it certainly reverses like an artic. not least due to the single pivot coupling at the back of the tractor. Our verdict? No problem.
Is the 18.65m Swap Trailer rig out of place on the open road? Based on our experience it's no harder to drive than a conventional full-length artic just so long as you remember what's happening at both ends-and make decisions to help other road users...