Pilot or trailing truck isolation

[twilight]

Looking for some ideas on isolating the pilot and trailing trucks on my Bowser L-1's. I had test ran them prior to painting and detailing them and I had got them all to run without shorting but now that everything is all back together and looking pretty good the shorting has returned. I am running the locomotives with plastic wheels on the both front and rear trucks. Let me know what some of you guys have come with to solve this problem. Also, I guess I should say that these locomotives are running with NCE decoders in them.


Thanks,

Mark

[MasonJar]

Is it shorting because of a connection to the tender? Many of these older locos had the power pickup from one rail in the loco, and the other through the tender. From the look of the diagram on the last page here <!-- m --><a class="postlink" href="http://bowser-trains.com/holocos/l1/L-1%20Ref%20Pages.pdf">http://bowser-trains.com/holocos/l1/L-1 ... 0Pages.pdf</a><!-- m --> it appears this may be the case. The reason I think this is because there is the characteristic open frame motor with only one wire. The other is actually the electricity being conducted through the loco's frame.

EDIT: This assembly manual confirms it <!-- m --><a class="postlink" href="http://bowser-trains.com/holocos/l1/100820.pdf">http://bowser-trains.com/holocos/l1/100820.pdf</a><!-- m -->. The very first instruction is about installing the insulated wheels of the drivers all one side. So even if you've put plastic in the pilot and trailing truck, if you haven't modified the drivers, frame, motor mount, and/or tender wheels, you will get shorts. Best bet would be to isolate the motor from the frame so the current from the loco doesn't reach the motor direct.

One other thought occurs if you have done all the above with your decoder install. Is one set of trucks on the tender reversed?


Andrew

[twilight]

Andrew, what I have done with the tender is molded the tender base out of resin. I am not using the original tender base any longer. The shorting issues I am having are occurring in curves. What I will do some time this weekend is take the locomotives to my club layout and run them without the pilot and trailing trucks to comfirm where the shorting is coming from.

My idea so far(haven't put together yet) on the Bowsers that have brass frames, is to change the mounting screw and bushing to plastic and some electrical tape where the spring touches the front pilot, also in the area where the front pilot screws into the frame. With the rear truck something similar with a plastic screw and tape or ultra thin styrene on the frame for isolation.

I haven't really worked out what to do with the front pilot on the locomotive with a zimac frame, because the mounting of the pilot is little different with the zimac frame, where the bushing is cast with the frame. I will probably file the bushing off and use the same method as mentioned above.


Hope that was clear,

Mark

[ray_m]

Did the shorting stop when using the plastic wheels?
Where the insulated wheels of the pilot and trailing trucks on the same side as the insulated wheels of the drivers?
Also be sure the insulating washer on the pilot truck is between the non insulated wheel and the pilot frame.
Another possibility is the flanges of the metal pilot and trailing trucks are coming in contact with the frame, cylinder, pilot or draw bar.
The flanges of the drivers may also be coming in contact with the pilot or trailing truck frames.

[twilight]

Ray, originally these locomotives came with metal flanged disks with a plastic core molded together to represent the lead truck/wheel and trailing truck and I also believe it pertained to when the locomotive kit was made. Bowser, I have found tried to make improvement with thier kits along years they produced them. When I had first assembled them locomotives(last year) some of them had come with the metal/plastic wheels, I have converted them over to all plastic aside from the axle and the locomotives ran without interuption ie: shorting for over an hour. Enough time to feel I had eliminated the shorting problem at that time. My plan is to take them up to the club this weekend and narrow down the problem as I had done before. Run them with both trucks, run them w/o the pilot, run them w/o the trailing truck. If they are still shorting then the problem may likely be in the running gear, like you had mentioned.


Mark