I’ve seen this on a new Bachmann GG1 as well as an Athearn SD40-2. It is definitely not plastic kitchen wrap. It seems to be intended to prevent scuffing of paint in areas where the loco shell might contact the plastic ‘clamshell’ container.There has been a 'foam like' but flexible thin plastic sheet
used in some shipments I've received. The reply from
Athern you mention, sounds like ordinary plastic wrap
used in the kitchen.