THE LONG
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AND THE SHORT
When it was first hinted that longer artics were going to be allowed on Britain's roads, operators were optimistic. But more than a year after the official announcement was made, many have disregarded the whole idea.
11 It is now more than a year since Robert Atkins, then Roads and Traffic Minister, announced that longer artics would be permitted on Britain's roads. Since then most operators have looked at the new limits, digested their meaning and promptly disregarded the whole idea. When they weighed up the opportunities for their own operation, many hauliers decided that little or no use could be made of the new limits. Either they were already running at maximum gross or axle weights, or they did not have the tractor units to pull the longer trailers.
Others dismissed the new regulations as the latest in a line of poor thinking to come from Brussels. The 16.5m artic is a product of the Continent. The Spanish were the first to use 16.5m artics, followed by the French. Both have 13-tonne drive axle weight limits, and so could take advantage of the simple two-plus-three artic configuration. Not all countries, least of all Britain, can do this.
Two basic problems presently afflict the UK. One is an extension of that which affects a number of other nations, while the other is peculiarly British. The first is the combined 10.5 tonne drive axle and the 38-tonne artic limit it helps to create. The second is trailer rental, and what its protagonists and users are to do about compatibility. Nowhere else in Europe are there two such enormous transport headaches.
For the rental companies, the problem of what to buy next depends on the amount of leasing business. Almost all commissions so far have been for fixed contract work where a tractor unit and trailer have been brought together as a matched pair. The volume and weight of the goods to be carried are invariably known in advance, thereby avoiding the risks of axle overload. Only the largest rental companies such as CTR and TIP have so far bought "long" trailers for their spot rental fleet.
PARTICULAR JOB
The rental customer is in one of two distinct categories. The first is the aforementioned long-term user where either the trailer or the entire combination is being leased for a particular job. The second is the spot-hire customer, someone who needs a particular type of trailer in a hurry and does not care much what length it is.
The first will have worked out the dimensions of his load and vehicle beforehand. The matched pair is created and the vehicle goes to work. There are few difficulties except for when either the truck or trailer break down. The spot-hire customer meanwhile will probably still be given an old-length trailer unless he specifically requests something different. At present such a customer is lucky to find many long trailers standing waiting. This is likely to change in time, however, as the returning contract trailers are found new duties.
The revised length regulations effectively permit trailers of 13.6 metres. This is achieved by a maximum 12m from the tail to the kingpin centre line, plus a maximum of 2.04m to any point on the trailer's nose. This gives a maximum kingpin position of 1,600mni on an ordinary 2.5m wide trailer.
In practice, the rental companies and most operators have not opted for the maximum dimen sions, but for something between the old and the new.
The reason to use trailers longer than the old 12.2m (40ft) dimension is to get two more pallets aboard assuming you use metric 1,200 x 1,000mm pallets, increasing the total from 24 to 26. This requires a little more than one metre increase in internal length, given the orientation of the pallet and some bulging of the load outside the pallet's dimensions.
The results have been different for the varying trailer types. For example, tilt trailers with their international lifestyle, and the fact that relatively light groupage loads are being carried, are coming out at the full 13.6m with 1,600mrn kingpin positions. Here, volume is everything.
The question of volume has not been lost on the trailer makers either. Schmitz Trailers and others are working hard on thin-neck chassis designs as slim as 40mm for maximum internal height. Here the body supports some of the chassis load.
Curtainsider trailers are still something of a British preserve. An ability to side load together with relatively thin bulkhead and rear door dimensions have allowed lengths of around 13.4m. Their practical use in this country has been helped by an amendment to the Construction 82; Use Regulations permitting a second forwardmounted kingpin position which enables coupling to older, shorter wheelbase, tractor units.
This amendment was proposed and pushed through by Pat Berridge, then with TIP, and now group technical director at CTR. It came into effect on 29 June this year.
Refrigerated trailers with their thicker walls and doors, and wider permitted widths continue to be the most testing types for operators. Internal length is the critical factor, which for 26 metric pallets requries at least 13.2m and more often 13.4m minimum for adequate airflow. Add insulated rear doors, front bulkhead and loads that bulge outwards from the pallet, often touching each other and the side walls, and it is a squeeze to stay within the law and maintain proper airflow around the cargo.
HARD LOBBYING
There has already been some fairly hard lobbying by reefer operators for even longer trailers to make sure that the cold air in a reefer can properly permeate a load of 26 pallets.
Transfrigoroute, the reefer operator's high-profile trade association, has already called for the statutory 12m deck length — currently set between the kingpin and the extreme rear of the trailer — to be redefined so that it is measured to the inside face of the rear doors, thereby improving airflow around a 26-pallet load.
Assuming a rear door thicknes& of some 150mm, such a move would inevitably lead to an increase in the overall reefer trailer length up to 16.65m.
Given the nature of the cargo, plus the current public concern over chilled and frozen food and Transfrigoroute's knack at lobbying, reefer men could well get a length concession in much the same way as they have gained extra overall vehicle widths.
However, Transfrigoroute isn't likely to let it rest there. While 16.65m will give a good airflow around 26 metric pallets it is less than effective for carrying 33 smaller 1,000 x 800mm Europa]lets. At its recent international conference it approved a plan to push for an overall trailer length of 17m. "Then you can guarantee the correct airflow around the load of 33 metric pallets," says Tony Palmer, president of Transfrigoroute International's technical committee.
Kingpin positions have inevitably become a product of the type of frontmounted fridge unit being fitted. They must be contained within an arc cast by the pin's centreline. And there are also moves to make fridge units smaller. Thinner evaporators are being tried to reduce the front-to-rear thickness of the unit.
Along with the new rules on length came a turning circle requirement. Trailers built or stretched after 1 April 1990 must, along with the tractive unit, be capable of turning within a "corridor" struck between two arcs of 5.3m and 12.5m. What first appeared to be a relatively harmless piece of legislation has proved to hold some far-reaching implications Newtandem-axle trailers built for use with three-axle tractors cannot easily meet the corridor rules in practice. This has made the two-plus-three combination dominant, and at a stroke has made rear steering axles even more attractive. But there are drawbacks in cost, weight and manoeuvrability. Few believe they will be adopted before the arrival of 40 tonnes, though they are available now.
TANDEM-AXLE
Tandem-axle trailers being commissioned by the rental companies are generally for use as 32-tonners (and 35-tonners when the forthcoming four-axle artic limits arrive on 1 January 1993). The use of air suspension is split between those who see it as a necessity for supermarket drops and those who say spothire customers will not pay the premium. Air suspension on tri-axles is now almost universal.
With the current maze of legislation governing longer trailers it is no wonder that the average operator is still confused about what length of trailer is suitable.
If operators thought getting axle weights right at 38 tonnes was difficult, then meeting the turning circle requirements of longer trailers, as well as keeping axle weights within the law (especially with diminishing loads) is an even bigger problem. And just how does the Department of Transport expect to enforce the requirements?
As most of the switched-on truck builders are using already computer programs to determine quickly whether or not a particular rig can turn in the required corridor, it seems that hauliers will have to rely even more heavily on the manufacturers to advise them on the right combination for the job.
But getting it right on a computer is one thing. Getting it right on the road can be a nightmare.
CTR's operations director Jim Brown declared in July that operators of large and small fleets were still "awash with confusion" over the new 16.5m laws.
In order to give drivers and hauliers some practical help, CTR has developed a simple measuring device that can be used by would-be trailer renters and which will quickly indicate whether the tractor they are planning to use will take the trailer swing of a longer trailer without the front of the latter swiping off brake connections or other behind-the-cab furniture. The device is little more than an adjustable pole which is attached to the kingpin and then extended to the corner of the trailer and locked. This then serves as a template for the tractor, by placing it in the fifth wheel and checking that there is sufficient swing clearance.
The measuring device is available at almost all depots and operators can bring their tractors in to check compatibility with CTR's latest equipment.
While CTR's measuring stick avoids the risk of any accidental damage when a "well it should be alright" guestimate goes wrong, it cannot tell a driver what his axle loadings are likely to be running with a longer trailer. Once again, the average operator will have to rely on trial and error and help from the manufacturers.
The next developments will result from continuing legislation covering matters such as swap bodies for road/rail intermodal operations within Europe. Body lengths and then vehicle dimensions will in future become a product of whatever standards are adopted within a deregulated Europe. There are already numerous demountable body standards in the community, few of which are compatible.
The outcome will also be linked to the outcome of the current round of discussion over drawbar dimensions. Drawbars, their trailers and semi-trailers can only be brought closer together. But who will gain? The long-term investment involved with trailers will probably pay no one, except perhaps the manufacturers.
O by Danny Coughlan
• For those operators who are looking at running longer artic ouOts, the problems of weight distribution and turning circles are described in detail in our Engineers Notebook in Commercial Motor 25-31 January.