I had several Walthers Heavyweight Passenger cars and tested the Diner with a Kato Business car my last trip out. The Kato went thru everything with style and grace. I figured it would fall off the track instantly.
It was the mean and onery Diner that fell off the track. So I stewed about the problem for a few weeks.
I discovered that the trucks were so tight as not to allow any sort of vertical grade climbing flexibility. I loosened the truck screw a little bit, still no go… wait a minute… what is that shiny tab under the frame over the trucks?
It turns out these tabs are for lighting electricity to light the cars. Since I never light the cars, out came the sisscors and yanked the tabs out. Suddenly that mean and onery heavyweight became sweet and docile across the terrible test track behind my 4-6-0.
I’ll hope to test them soon as a train and see if they run as well as that Kato did.