I wasn't thinking about complete rakes, just how to transport and store a roster of delicate N scale cars which can be taken out or replaced fairly quickly. At the end of a show there is a temptation to just pack the boxes any old fashion and sort them out later. HO cars are reasonably tolerant of such handling but I expect N scale needs a bit more care and finesse.
These 20 litre boxes are brilliant for HO cars. One or two full boxes is enough for one person to carry, and it only takes a few trips between the van and the exhibition hall to transfer the full roster.
Having just revisited their web site, I see they also list these 10litre boxes which might fit the bill. I suppose its flexible enough that you need only have as many as you need.
Oh dear, its beginning to look like I am answering my own question.
I do wonder if there is something like a large lightweight box with a stack of pull out drawers. While I think a foam lining is the solution for heavy items like camera lenses, I have lost delicate parts off some models when they have become entangled in the foam. I'm getting hungry looking at those cakes now...