Yea the difference is BiFri travel bikes , is a Knock down and fold combination..


not a case .. but.. trailer wise I have a Carry-Freedom,City trailer I got for my Brommy

If there were a cross over design for the B&W design as a trailer Kit.. I offer thoughts..
the CF,C tow is at a right angle to the bike , the hitch, a ball end elastomer , fitting in a cup hitch.

(Chariot kid trailers same hitch)

the rear Brompton fold as Kickstand still works , because of the ball hitch, and the folding handle's squared bends..


CF,C cleverly folds flat, 2_ 12.5" on their own forks fold within the frame, a sling bag pops out of that space..

and the handle/tow bar folds up.


Because the Bag is a sling below the frame square, the folded up Bike can be pulled along on to of the trailer Bag.


And now back to your regularly running topic...