I recently received shipment of two Atlas 60' passenger cars (4 wheel trucks) and a matching baggage car (6 wheel trucks). Running them on my layout that uses Gargraves track and Ross turnouts, I found that they would hop, jump and sometimes derail as they ran thru the turnouts. It was especially bad on curved turnouts and the diverging leg of straight turnouts. Initial inspection led me to believe that the pick-up roller assemblies were causing the problem. To get a better look, I disassembled the baggage car and removed the trucks. I was then able to get a better look of the pick-up roller action as it crossed a turnout. What I saw was that the pick-up assembly was able to tilt sideways and the roller wood wedge itself between two adjoining rails. Continued movement of the truck would then cause it to lift and the roller would be released. I found it would happen in either direction of travel.
My first action was to call Bill Seratelli at Atlas and get his input. He had not heard of the problem but did acknowledge that from the photos I had sent him, there seemed to be a fair amount of travel in the pick-up assembly. He had no Ross switches to test the trucks on at the time.
I decided to try and find my own cure. The pick-ups have more than a fair amount of travel both side to side, front to back and up and down. Even the rivet that holds the assembly together as play in it. Very sloppy. It appeared that the only thing I could attack was to try and limit the up/down travel of the assembly. If I could limit the down travel, perhaps the roller would not drop far enough to wedge itself in the rail voids. Let me say that the cure would have to be with the roller and not to the Ross switches. His product has been around for a long time with no complaints and since I have 99 of there turnouts on my layout, I was not going to modify them.
I determined how much actual downward travel of the pick-up roller was needed to have it stay in contact with the center rail. From that I found I could install a 1/16" spacer in the roller assembly to keep it from dropping to its lowest travel. I fabricated a simple spacer of 1/16" plastic approx. 1/2" long by 7/16" wide. I cut a channel in part of it to clear the rivet stem that held the pick-up together. Pushing the pick-up assembly up I could now insert the spacer between the mount and the movable pick-up arm. I used CA to fix it in place. I reassembled the car and ran it along with the yet unmodified two passenger cars. I now had smooth running on the baggage car while the passenger cars still had problems negotiating the turnouts. I think I might be able to make the same modifications on those cars without taking them apart. I'll let you know.
The following are the pictures I took for reference. The first are of the trucks and how the roller is able to tilt and get wedged. Follow those are pictures of the pick-up roller assemblies, their construction and the gap that will be filled with the spacers. I can't believe that I am the only one that has experienced this problem.