3.1. In addition to the characteristics described in section 3, the road trains must have the following axle characteristics:
(1) the tractor has a single front axle and a tandem axle, interaxle spacing of not less than 3.5 m measured from the axis of rotation of the single axle to the axis of rotation of the first axle of the tandem axle, and a wheel base of 6.2 m or less measured from the axis of rotation of the single axle to the centre of the tandem axle;
(2) the first semi-trailer in a B train double has a tandem axle or a triple axle, and the first semi-trailer in an A or C train double has a tandem axle, a triple axle or a Class B.44 or B.45 four-axle group referred to in the Vehicle Load and Size Limits Regulation (chapter C-24.2, r. 31);
(3) the second semi-trailer is equipped with a tandem axle or a triple axle; and
(4) the interaxle spacing of the tandem axle or triple axle, measured between the axis of rotation of each axle, does not exceed 1.85 m.
Until 31 December 2009, the first semi-trailer in an A or C train double may, despite subparagraph 2, be equipped with any tandem or triple axle group on the condition that the semi-trailer was built before 1 March 1997, in which case subparagraph 4 of the first paragraph does not apply.