Found this 0 scale two rail flange alignment version at a large gauge train show at the York fair grounds maybe 10 years ago. Very similar to one they make for G "scale".
One can set a couple dozen regular freight cars on the track in a minute or two.
It is great for two truck cars but a tad too steep for four truck flat cars. OK for moderate length steam engines but not for GG-1, PRR T-1, Centipede or other out sized rigid wheelbase item. The first axle and last axle tend to suspend the mid wheels and fail alignment.