Rod -
Certainly use of a graded spur for car movement was done in many instances. But I'd worry about slow-motion run-aways. If there was some issue with the brake shoes slipping, or the hand brake linkage on a particular car, away it goes.
One neat method I've seen to spot cars at a facility spur is a machine called a "windlass". I saw such a thing in operation several times at an industrial facility where I was consulting. It's apparently a common device in marine operations for rope tugging of vessels. While their equipment was modern, the trick seemed right out of the 19th century. (Sorry, I didn't have an opportunity to take pics.)
This facility needs to move almost daily one or two UP-delivered covered hoppers a few car lengths along a short level spur for unloading of bulk perlite (a relatively low-density load to be sure, so car was certainly below it's rated gross weight). Their windlass is a motor-driven horizontal steel pulley (vertical shaft) about 2 feet diameter and a foot or so thick, with a deep, rounded slot. They use a large diameter (like 3") cotton rope - I'm sure nylon or polymer fiber rope would
not work. The rope is attached securely to the end beam of the car to be moved, the other end is looped around the driven windlass pulley.
Then, one man pulling on the free end of the rope could tighten the loop just enough to briefly engage the spinning steel pulley by friction on the rope (why plastic rope is no good). The guys I saw doing this obviously had practice. They would tug casually on the rope just enough to get the car(s) moving very slowly. It seemed easy to gently let the car stop right where they wanted it. I don't think they even used the car brake, but if I recall there was a guy up there just in case. There was another similar "idler" rope pulley at the other end of the spur, and they could loop the rope around the far pulley to use the windlass to pull a car the other direction.
Bob of AZ
