double-deck

1. not comparablehaving two decks or levels, one above the other

   The normal methods of road delivery are by driving the cars individually, or by car transporters which convey as many as eight vehicles on massive articulated double-deck trailers.

   1960 June, “British cars go by rail: I-The L.M.R wins new Anglo-Scottish traffic”, in Trains Illustrated, page 335

   1 more example

   The 'Superliners', the double-deck passenger cars intended for long hauls, were the subject, not only of internal disputes at Pullman Standard, but also of a contractual disagreement between the builders and Amtrak.

   1985, Rodger Bradley, Amtrak: The US National Railroad Passenger Corporation, Blandford Press, page 127

plural double-decks

1. Philippinesbunk bed; double bed