Strong Non-conductive Drawbar Material

Epoxy (green) circuit board. Maybe you have some dead electronic boards laying around somewhere. Unsolder all the components and sand the copper plating off.

Pete

Hi Ed

The short is likely in the area of where the drawbar mounts to the engine’s frame through an insulating nylon bushing.  Typically there will be a threaded metal lug with a wire coming it above the frame.  The drawbar screw threads into the lug.   Sometimes with over tightening  the lug rotates and makes contact with metal under the cab.  Recommend before you go to the trouble of replacing the drawbar remove the boiler  and check out what is actually causing the short.  Often the fix is quite simple.

If you find that the plastic washer ( It's a stepped washer) referenced above has cracked or broken in some way you can get replacements from Sunset. You'll need to get dimensions as there are several different ones. I recently got one from Scott Mann at Sunset.

Bob

Ed and Bob,

I have checked and the only way the screw does not touch is if it is loose.  I can make a drawbar easier than re-engineering that area.  I found a strong, non-conductive fiberglass bar at McMasterCarr and have ordered it.  It should be here Wednesday.

Thanks for the input.

Ed

I'm with Pete, I use 1/16" fiberglass board stock for stuff like that.  I've made a few drawbars from it, they have never failed.  One caution about working with fiberglass!  Fiberglass eats saw blades for breakfast!  Unless you have a specific fiberglass blade, I'd rough cut it with a Dremel fiber cutoff wheel, then fine shape it with a grinder or file.  Oddly, I have no problem with the fiberglass dulling my drill bits, but a couple of cuts and my bandsaw blade was so dull it can't cut soft pine!  I knew it was hard on blades, but I had no idea it was that hard on the blades!

Bakelite works too.  Having fooled with conducting drawbars, I would say you are aimed in the right direction.  Use sub-miniature connector pins and shrink tube for electrics.

Guys,

Thanks to all.  The engine has DCC and fortunately does not require the drawbar for conduction.

I will lay in a stock of cut-off disks and hacksaw blades for the cuts.  Good news that it does not affect drill bits much.

Ed

If you have pickups on the tender trucks insulated wheels running to your motor, make sure they on the same rail as the insulated wheels on your locomotive. Those should have pick ups also running to the motor. The wheels on the other side of both the locomotive and tender are the "ground" side and have the same polarity so the drawbar does not need to be insulated and can remain metal. 

Peter

Clover House makes PCB tie stripes for module end ties, They are 0.375" in width and several inches long. Just cut to draw bar length, and drill holes for the lugs. I shape them with a cut off disc. Do this outside as it makes some dust. File or shallow cut a gap in the copper overlay, paint with Golden brand artists acrylic paint[adheres better than the cheap stuff] and you are good to go. Make two identical ones with a little styrene spacer and you have double draw bars like the real thing or the expensive imports.   jefferson