Have you ever converted a Walthers Ore car or any bottom unloader by fitting working bottom opening door’s, Hornby did an ore car with opening door’s, did any American firm make anything like it. I’d like to run an Ore train to an unloading dock and unload it as the real thing does. There have been articles on how to make a working loader but i have never seen a working un-loader
This is the Hornby OO gauge model, you can see the working hinged bottom door, it’s designed to be slowley pulled or pushed along to do the unloading cycle

This is how it work’s, upon entering the unloader the catch on the right strikes a post releasing the door downwards alowing the contents to drop out

Second the arm which is attached to the door get’s pushed up closing the door, this is while the catch on the right is still held open

finally the catch on the right clears the post allowing it to lock the door closed

i think this system could be made to work on an ore car, as for a suitable material, photo etched brass would work well, a section of pipe or lift rings could be soldered on to form the door hinge with a steel wire forming the door lifting lever soldered to the door at the hinge, i say photo etched brass as it would be a good method if you have loads of ore cars to equip.
How much fun would it be to drive an ore car train through an unloader watching it emptying before your eye’s, great fun i recon
I have never seen a working ore car in HO. Are you sure you want to pick up all of the loose ore after a derailment? Besides, the real stuff is sort of sticky at times and has to be poked from the top by workers with safety harness equipment.
BTW, Mantua/Tyco and Ulrich both had working hopper cars back in the late 50’s/early 60’s. I had one of the Mantua 2 bay hopppers. It had ‘clamshell’ doors that closed by gravity, and a special ramp spread them so the load could dump. It really did not work too good, and the material did not ‘clear’ every time. Also, the clam shell doors on the gate would leak material all the time. I learned my lesson and use removeable loads now!
Jim
That system could probably be made to work, with a lot of tinkering and fussing. The only question would be, is it worth that much of your modeling time and effort?
Unfortunately, using a rotary dumper is not an option. Rotaries (and tilt dumpers) were used for coal, but the integrated design of ore cars, ore piers and Great Lakes freighters requires the cars to unload into specific ore pockets by gravity.
I have a colliery that loads hoppers and gons with (char)coal, but they are unloaded by dumping when they reach down storage. (Yes, my railroad runs up and down, but up is toward Tokyo, not London.)
On this shot, you can see the clamshell door at the bottom of one of those old Mantua operating hoppers:

(click to enlarge)
I have yet to run live-coal through these these, but I remember doing it 40 years ago. I think they worked reasonably well, although cleaning up after a derailment will really give you incentive to make your track as perfect as you can. As for unloading, it always worked cleanly for me, so I guess the trick is to use the right material for coal. I’ve still got a couple of bags of the original coal I used, and it looks a lot like the WS “cinders” black ballast.
You could try it the LTV way. Have a tire on the side spinning the door open.