WEIGHT PLANS TAKE SHAPE

The author outlines the government's proposals to increase the weight limits of articulated vehicles and drawbar-trailer systems to 40 tonnes for five-axled outfits, discussing their implications and outlining possible configurations to suit the higher weights. The length limit for articulated vehicles is to be increased to 15.5 M but drawbar outfits remain limited to 18 M in length. Two-axle tractors will be able to operate with suitable trailers at 38 tonnes, but a three axle tractor is essential for 40 tonnes and it must have a double drive. The drive-axle limit for a two-axled tractor operating at weights above 32 tonnes would go up to 10.5 tonnes. Methods of converting tractors from two to three axles are discussed. Problems could be encountered in meeting the required minimum separation of the axles. The maximum length of the semi-trailer will be restricted to 12.2 M. The height limit of 4.2 M applies to every motor vehicle with a train weight of over 32 tonnes. The advantages of drawbar combinations in the increased deck length available and the ability to split loads are investigated. (TRRL)