Unlike a lot of Europe, Sweden has quite a progressive attitude towards the development of higher productivity freight vehicles on its roads. The ‘monster trucks’ in Sweden are permitted by rules which allow for long combinations up to 25.25 metres long to run at a GCM of 60 tonnes on many roads in the country.
This combination can be made up in one of two ways. Firstly, the truck is a rigid with three axles and a freight carrying capacity using a dolly to pull a full sized semi trailer, essentially a truck and five axle dog. The second consists of a full sized semi trailer pulling a pig trailer behind it.
Plans are afoot for the government to allow longer combinations again in the near future. The idea is to go to an A-double set-up, similar to the combination developing in Australia. The maximum GCM allowable will rise to 75 tonnes and the two triaxle trailers are the standard 13.5 metre type already in use. A tandem axle dolly connects the two trailers.
Swedish operators tend to specify 6×2 prime movers to do this work. The tag axles can then be lifted when unladen. These single drives are used on roads which are often dirt in country areas and will be covered in snow in winter. Even so, only a minority of operators choose 6×4 as a drive option.
There are two examples of this kind of A-double combination currently running on Swedish roads on a trial basis. One is a timber truck hauling out of the forests of Northern Sweden, the other is an A-double set used by Scania Transport Labs, running truck components from its base in Södertälje to the Malmo ferry in Southern Sweden. This combination is then broken up and runs as two singles into Zwolle in The Netherlands.
The road testing involved in the launch of the New Generation Scania models in Sweden also gave Diesel News an opportunity to try out these combinations in a real world situation on the local roads south of Stockholm.
As with any longer combination the various units tend to follow the prime mover surprisingly well. On the evidence of traffic on the highways of the country, Swedish operators seem to prefer the rigid and long dog combination. The original idea in giving a choice was to aid utilisation, a pair including one of each type of long combination can be broken up into two semis and rigid and pig set-up with the addition of an extra prime mover. However, the industry has chosen the long combination which handles better.
Taking these long trucks out onto Swedish roads proved to be pretty painless. The rear overhang on the lead truck brings the dolly out wide on corners and the triaxle trailer follows well. Manoeuvring around relatively tight roundabouts in the middle of a small town proves to be easy and the paved run off in the centre of each roundabout was not needed.
The experience in Sweden echoes the results found here in Australia, where PBS designs involving rigid trucks with long dog trailers has been the majority of new higher productivity trucks on the road, so far.