Think there may be a bit of a problem here; the ‘original regulations’ Road Vehicles (C&U) Regulations 1986 allow a vehicle combination where the tractor unit has at least 3 axles and a relevent axle spacing of 6.9 metres (from the centre of the tractor rearmost axle to the centre of the rearmost axle of the trailer) to run at 38 tonnes.
New regulations were adopted in 1999 (The Road Vehicles (Authorised Weight) Regulations 1998 (SI 1998, No 3111) to align weight limits in the UK with those imposed by EC Reg 96/53
These regulations allowed 6 axle tractor/trailer combinations to run at 41 tonnes, provided the following criteria were met;
- the weight of each driving axle does not exceed 10 500 kg
- either; a) each driving axle is fitted with twin tyres and road friendly suspension or b) each driving axle which is not a steered axle is fitted with twin tyres and does not exceed 8 500 kg.
- each axle of the trailer is fitted with road friendly suspension
- each vehicle comprised in the combination has at least 3 axles.
Road friendly suspension is defined by EC 96/53 where road friendly suspension is air suspension or a suspension regarded as the equivalent of air suspension where at least 75 % of the spring effect is caused by an air spring and an air spring is a spring operated by air or other compressible fluid under pressure.
In 2000 SI 3224/2000 ammended the new regulations to allow operation at 44 000 kg for six axle combination that complied with the above, provided they were fitted with a Euro2 or above engine.
So what is the consequence of all this mumbojumbo?
Basically, if both parts of the combination are not fitted with road friendly suspension then the maximum permitted train weight is 38 tonnes, irrespective of what the Ministry Plate says. If you don’t believe me ask the drivers that got done taking sugar beet into Newark a couple of years ago. They had ‘air’ tractors and ‘steel’ trailers and the Ministry went for the 38 tonne train weight.