I have several older Walther Amtrak passenger cars with some of the worst trucks I have seen. Not prototypical and very high friction even with the interior lighting brushes out of the way.
What should, or could, I replace the trucks with?
Walthers has the Lightweight Passenger Truck – GSC 41-N-11 w/Disk Brakes (Black) Walthers Part #: 933-1305 or GSC 41-CNS-11 w/Disc Brakes (black) 933-1306 on sale at the moment.
If the trucks are causing you problems as being wobbily then replace them. If they are high friction then there are two things you can do. You can get a truck tuner from Micromark. This tools reams out the journals and allows the wheel to turn better. The second thing will help out the most. Apply a drop of plastic compatible oil to each end of the wheelset. This will make them spend a whole lot better.
I have done the following suggestions on my Walthers Superliners and it has improved greatly. It will also cause less strain on your locos.
Good luck.
The journal reamer mentioned above works wonders on Walthers metal wheel equipped trucks. The before and after difference is huge and allows the axel to properly fit and rotate. I lube with graphite instead of oil.