Two questions.
1. If you slowly rotate the bed, does it successfully dump the coal? That is, I'd think one benefit of violently snapping the coal bed is to impart some momentum to the load.
2. If I understand the design of this particular coal car, you don't really need to be all that accurate on the normal and dumping angle? In other words the total range of motion for direct-drive looks like about 45 degrees (vs. the >180 degree range of a servo). So if there are angle resolution issues (not saying there are) in the servo mechanism, it's OK to be off by a degree or two on either side? In other words nothing would be stalling the servo motor in the normal or dump angles if the servo angle is slightly off.
