Not one to resist a challenge I decided to atttempt to make one for TS2013.
I tried to solve the problem by using a transferpoint as the tippler and an animated wagon which would tilt in time with the transferpoint. At first it wouldn't wotk, but, thanks to Dave Dewhurst, the error in my blueprint was spotted and corrected and the idea came to fruition, as seen in the video.
Still obvious problems with the animation, but it seems to work ok in principle and I need to fine tune the animation.