I am in the process of painting one of those nice old Kumata brass Kettle Valley sets. The cars are nice, and include a tapped 1/72 hole for the kingpin screw. I have bought some Precision Scale 2 axle trucks for the bag and mail cars, and use basswood Northeastern bolsters between the truck and car floor. Unfortunately, the assembled car and truck combination shorts almost immediately. Has anyone ever had this kind of problem with these trucks?
Would a nylon screw avoid the problem?
An alternative would be to make an insulating bush instead of the tapped hole.
Try putting the trucks on the rails without the car. Any short?
Does the car have some sort of continuous metal underframe into which the trucks attach? If so try turning one of the trucks 180 degrees.
It may be obvious but here goes. Be sure the insulated wheel is on the same side of the truck frame. Some of my brass trucks have all four wheels insulated but others are only insulated on one side. Sometimes it is easy to tell which wheel is the insulated one. Other times you should use a continuity tester.
Good Luck, Ed
Thanks, guys- this is all useful advice, and I tried all of it before posting. The biggest problem seems to be that the individual trucks sometimes short, and sometimes do not; it’s not a continuous problem. I was able to get one pair working reasonably well last night, will have to see how the next ones do.
You’ve tried individual trucks with only occasional success. Occasional success isn’t going to be usable.
Are these brand new trucks, never been used before? Have you tried individual wheelsets? I had a wheelset that shorted out once. That wheelset was promptly demoted to scenery.
can you re-read what Ed said and make sure that both non-insulated wheels are on the same side of the truck?
I can read, and I checked them for that problem before I posted. I’m quite capable of discerning whether the little black discs on the inside of the wheels are located on the same side of the truck.
For the polite responder, I have not removed the individual wheelsets to check them- that would require de-soldering the truck just to test them, and I’m hoping that I can find a solution short of that. Thanks-
i have a hard time telling which side of intermountain wheels are insulated and check with an ohm meter
is the car frame metal and the wheels hitting the frame?
In the past, there was a case where a Japanese brass truck had a short circuit at the “x” parts in the diagram. I don’t think this will happen to you, but please check.
I had never heard of defective wheels (shorting) but I guess it’s possible. Some steam loco drivers can short.
Changing wheels should be easy.
Simon
Not if he has to unsolder the trucks.
Another question. Do these trucks have brake shoes? If so one or more of them may be contacting a wheel.