Yesterday I saw a caboose advertised as LGB. ON the side (both sides under the railing) of the caboose you could plainly see Aristocraft. So here is what I have found:
Aristocraft have a unique hook/loop coupler design. LGB, USA, LGB all use similiar hook and loops although the Bachmann ‘spring’ is much thinner plastic.
LGB/Lehman have their logo on the bottom of rolling stock. Also the gold sticker is a date code.
Bachmann has their logo on the trucks on some of my rolling stock.
Usa trains may have Charles RO or even Malden (store in Malden, MA) onthe bottom of rolling stock.
Delton logo on bottom of freight, passenger cars have nails holding the roof in place.
I hope others chime in with what they see for verifying manufacturers.