Have a lookat this video. I am going to give it a go as I rebuild my layout.
It is from the gn15 site, sent to me by Greg Hunter.
I was thinking of making a loader using a servo to operate a butterfly valve from a small carburettor to drop the load into the wagon.
I found while experimenting that the load must be dropped very close to the ore car becuase the gravel or clean cat litter will tend to bounce out.
Try dropping something into you cars to see what hight is reqiured for minimum spillage or you will spend more time cleaning up than loading cars.
http://www.gn15.info/a-working-wagon-loader-the-movie/
I am hoping to have some working aspects for large scale trains.
There is some great scratch built stuff for HO railways but not much for large size.
Cheers from Andrew
Sandbar & Mudcrab Railway