Best way to attach caboose cab to frame, so it is removbable.

Drill 4 holes in the frame, one at each corner, then add if needed (it will be), at each corner of the body, 4 styrene "posts", say and inch long and fat enough to take your screws. Drill smaller pilot holes in the posts for your screws. Use plain model cement, like Testors, to attach the posts at each corner. Run some small screws - small wood screws or sheet metal screws - up from beneath and voila! - you can unscrew your cabin/body.

Square posts are better; Evergreen styrene is widely available. Hardware store for screws. 

Snugly fit a block of wood in the shell and then use two sided tape to secure to the car.  No drilling or glue and easy to remove. 

I've had good luck gluing magnets on the base and inside the body.  Just line up and your roadworthy.

Corner posts hold best. I use wood s& small  supedots ofrglue and epoxy both..... (small dots of superglue ).

L-brackets on the ends if you don't mind a screwhead on the doors 

Odenville Bill posted:

I've had good luck gluing magnets on the base and inside the body.  Just line up and your roadworthy.

I second the magnet idea.  I just did this with a fuel tank on a diesel engine for easy access.  It works great.

Ron

Thanks for the suggestions.

Mark

You could place a steel bar along each side of the floor.  Place two magnets on the inside of the cabin.  It may not hold if you try to lift the entire car by the cabin, but it ought to be strong enough to hold the cabin in place while running.  John in Lansing, ILL