Which trailer configuration is specifically identified by the AAMVA CDL Manual as prone to getting stuck on raised railroad-highway crossings?

AAMVA CDL Manual, Section 6.1.4 'Railroad-highway Crossings,' p. 6-2

Knowing which trailer types ride low to the ground helps a driver anticipate ground-clearance problems before approaching a raised crossing, rather than discovering the hazard mid-crossing. This is especially relevant for drivers who regularly haul heavy equipment or livestock in low-slung trailers.