Well I think I found the problem. I checked the rods and one seemed stuck jammed as John (Steam Crazy) said above. The bolts seemed tight with a bit of free play when the bolts are tight. But one seemed stuck somehow. I loosened the screw that holds the black vertical part that I show in the photograph. The screw is under the boiler. I forgot to take a photograph until it was all back together. With that loose, I could never get it to jam. I think it was tightened down a little crooked. I tightened it, and ran it back and forth over and over many times at various speeds. I finished by lubricating the wheels and all the moving points on the rods. I think that took care of it. I put it on the temporary Halloween layout, and will run it more. Time will tell.
Thank you everyone who contributed!! I learned a lot. In all my days in various scales, i never had a problem with side rods before. Hard to believe.
