Pretty much all steel cabeese were OK for helpers behind. Espee did restrict classes without roller bearings to local service in more recent times. Some railroads placed limits on how much tractive effort could be used behind a certain class of caboose. Others were over - designed for such use, such as the Lackawanna's Keyser Valley - built steel cupola cabeese featuring cast underframes reused from steam locomotive tenders !!! I believe Rio Grande ??? had cabeese outfitted with platform - mounted pin lifters for cutting helpers on the fly. Ah the good old days...