Three legally configured goods-vehicle combinations are being checked: a B-train, an A-train, and a heavy rigid truck towing two other trailers. For the third combination, the rear trailer has a GVM of no more than 3.5 tonnes and the whole combination has an actual gross mass below 20 tonnes. All other applicable requirements are met. All operate within the standard dimension limits in Schedule 2, with no approved dimension variation or exemption (including under a 50MAX proforma), and no load projects beyond the vehicles. What is the maximum overall length for each combination, including its load but excluding collapsible mirrors?

A B-train has two semi-trailers, with the second coupled to a fifth wheel at the rear of the first. An A-train has a semi-trailer towing a full trailer. The other two-trailer arrangement in this question requires a heavy rigid goods vehicle, a rear trailer with GVM no greater than 3.5 tonnes, and actual gross mass of the whole combination below 20 tonnes. These conditions do not replace other coupling, axle, mass, stability or licensing requirements. The 20-metre answer is for the stated operation: certain reduced-width loads projecting behind a rear full trailer can have a different overall-length limit, and overdimension or special-permit operation must be checked separately.