A couple more things:
(1) I had to add two small cardboard strips to both sides of the neodymium magnet to assure that the culverts would go straight through the two little gray doors. See figure. I used superglue to affix them.
(2) Putting a drop of Labelle oil on the gray door hinges seems to help.
(3) When you're done unloading culverts, park the hoist in its left-most position.
(4) Don't attempt to raise the hoist without a culvert load. There needs to be tension on the hoist string to keep the string from tangling up inside the hoist housing.
(5) The culvert loader is pretty reliable. Just remember not to leave it in the left-hand "grabbing" position. Doing so will cause the first culvert to come down the shut to knock it cockeyed and prevent it from being grabbed.
Good luck! When this thing works, it's really entertaining.
Hal