I have a Nscale rotary coal dumper .
It was manufactured 30 years ago and I beleive in very small quantities by State Street Models owned by Mister Rick Spano ,a well know and precursor modelist in Nscale.It was also reviewed in MR "New Products" at this time.
Mister Rick Spano layout is featured on a web site whith picture of a Rotary in Nscale but I don't remember the address.
It is a pewter kit very hardly constructed.
For the story, my late father ordered it for my birthday.
I have buid it and dismantled it soon after and left the parts in a box.
But I project to rebuild it because my new vision of my maclau river is now meanly inspired by the N&W which owned one of two rotary at Lamberts point terminal.
What I remenber whith this kit and as a rule is to use only one brand of hopper; it was designed for 33' hopper and I use only MTL hopper.
For a scratch project , may be use a Micro enginering deck girder bridge; use a small aluminium tube like Mr Koester used in his tall viaduct project to it more rigid.
You can cut the two round end in a small aluminium plate;some little iron factory could do the job.
The chutes could be made in styrene.
The pressure arms which retains the car when rotating are more difficult to do and I don't remenber how they work on my model but I get to take a look and made some pictures I will publish in this post in the coming days
I beleive also MR had published an HO plan of a working Rotary in end of the 40's or begining of the fifties.
Some which own the New CD of the MR complete issues may find the plan; it was also published in an extra old book by Kalmbach for scratchbuid projects.