Jaggar
Every problem is different. I have 50 or so engines of all makes and wheel configurations that all work fine most of the time. Recently I had an issue with the Marx 333 4-6-2 on the Lionel uncoupling section (the ones with the red plastic center).
The engine would stop and reverse and stop and reverse on the two or three of the sections but not on the 10 to 15 other ones. I bent on the brass sliding pickup and tried to make it look just like the one on the good working 333 for a day or two. Finally I noticed one of the driver wheels was loose on the axle and was able to tighten it up by gently hammering it on better. That improved it and it now works better but still acts up after a few minutes to running. It has been troubling engine and had a shorted out armature which I replaced.
This Marx 333 front 4 wheel truck also would derail on some 027 curves. I had banked the curves with about 1/8 in rise on the outside rail. All other engines never had a problem with these curves for 40 years. I removed several of the wedges to flatten the curves and that fixed that issue. I do not think the banking made it possible to go faster around the tight 027 curves anyway.
Another problem was a new to me, Lionel 561 0-8-0 switcher that derailed on several Marx 1590 switches. I found the edge of the moving rail part of the switch of a couple of them were not real tight against the rail it edged up to and bent it to close the gap. Again none of the other engines had a problem like that.
A couple years ago I got a like new to me, Williams ABA Santa Fe F 7 diesel set. It shorted out on many Marx switches. I found the pick up rollers were too wide causing the shorting out. I ground a little off the rollers edges that fixed that. Then the engines would derail on so some track joints and at the hump at three bridges as the track was higher on the bridges ( the metal of the bridge base made the bridges higher than the approach tracks). I bent the metal tie bases flat on the bridges to lower the track on the bridges and installed thin pieces of aluminum flashing in the gaps at the track pins. The powered unit would run only in reverse so I reversed the lead to the dc canned motors to let it run in forward only which is fine for me now.
All these issues make my tracks smoother and better for running all the engines. I find when I drift from my Lionel 242, 2026 and 2035 engines and go for other makes and diesels and 8 wheel configurations operations are not as smooth. I have had good experiences running Lionel 2046 and 2065 baby Hudson's. My layout is a switching (as in changing routes not making up train consists) and operating layout with 28 Marx switches and a homemade turn table so it has lots of pit falls to smooth operation.
Charlie
