been produced with between 2 and 6 axles, semi-trailers (both A or lead and B types) have been produced with between 1 and 4 axles, pig trailers have been produced with between 1 and 3 axles and dollies with between 2 and 4 axles. Table key for section 8 of this TAP below:- ‘* GCM is limited to less than the sum of the axles and this may vary