Steve, I think we may be talking at cross purposes, as I think what I said was right but I also agree with what you say. Not that the mechanics of the process matter, the point is we're all convinced Gordon can take a stone up a hill like a rat up a drainpipe and no-one else can!
Pardon my ignorance but who's Mr Otis?
Gordon, I can see your point about being the brakeman, and I suppose you'd be better at it than a mechanical brake, as that wouldn't kick in until the stone started slipping back, it's just the thought of you stumbling or coming over all funny at the crucial moment...