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Fellas,

I have a MG PRR M1 and a USH PRR M1a that I double-head to pull my 30 car (Atlas) coal train on my club layout which for now is straight DC.  Several years ago, I re-motored both using Pittman 9234 BB motors.  Recently while pulling my coal drag, the MG model started to run intermittently causing me to think that a tender wheel cleaning was in order especially considering that the MG tender has 33% fewer wheels to conduct electricity compared to the USH tender which was running well.  Also, the USH headlight was steady most of the time while the MG headlight was not steady.  (Yes, I like my 12v bulbs.) Cleaned wheels on both engines and tenders with little discernible difference.  Still convinced the problem was in the MG tender, I removed the trucks, noticed corrosion on bare brass bolster and insulated washer that it contacts.  Removed corrosion with a file and reassembled.  Problem solved.  Question:  Should I use a conductive grease or oil where the insulated tender pick-up washer meets the bare-brass span bolster to reduce corrosion issues?  What do you use?

Tia

Last edited by PRR 5841
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I use thin oil. I don't like any wearing surface to be dry.

 On some engines, I have added wipers to the wheel backs in various spots of the engines to help them get over dead spots and to spread out the power draw better. I don't like having all the power picked up from just one point. I think that can create pitting and/or other problems. I run with sound and smoke that draws more current.

Wahl Hair Clipper oil is a very thin oil, like the old sewing machine oil that works well in that application.     It can be purchased at beauty salon shops (specialty shops that sell ladies makeup and such) and I guess barber supply shops.    

Put it on sparingly

another option would be mineral spirits.

Both have good dielectric constants to avoid arcing and corrosion from the current flow.

I have had similar problems with USH engines.  Rather than oil, which tends to migrate, you might try conductive paste.  I use Gardner-Bender "Ox-Gard", after founding out that it works excellent in outdoor ground light sockets.  I have used it on several engines with no recurring problem.  Before applying it, I used 320 grit sandpaper to remove the tarnish buildup on the bolsters.  I do not know if it just eliminates tarnish buildup, or if it is conductive, but I believe it is.  I understand there is a similar product called "No-Ox" (or a similar name) but have not tried it.

PRR 5841,

Sorry, I didn't mean to offend you, but your explanation said "bare brass bolster" and corrosion, so I thought your engine was unpainted.  Is it common for 2-rail O scale engines to be painted while leaving the bolster bare?  Is a bare bolster necessary for electrical conductivity?  If unpainted, I was afraid that using the products you were thinking might interfere with a later attempt to paint.

Chuck

PRR1950 posted:

PRR 5841,

Sorry, I didn't mean to offend you, but your explanation said "bare brass bolster" and corrosion, so I thought your engine was unpainted.  Is it common for 2-rail O scale engines to be painted while leaving the bolster bare?  Is a bare bolster necessary for electrical conductivity?  If unpainted, I was afraid that using the products you were thinking might interfere with a later attempt to paint.

Chuck

Chuck,

No offense taken whatsoever.  There’s a shouldered screw w/spring that holds the truck to the tender.  The bolster is painted except for the part that contacts the brass “washer” with tabs that fits underneath a block of plastic for insulation.  Any good painter will remove paint from this area before reassembling the model.  The washer has a wire soldered to it and together with the wire from the other truck, connects to the backside of the female tender plug and you have electrical contact or least in theory until corrosion compromises the connection.  This arrangement enables a “Cold” tender as opposed to earlier iterations from KTM (MG) that didn’t have the plastic block which meant the whole tender was “Hot”.  A real problem if the cab deck plate or drawbar weren’t insulated.  

Sorry if my response caused you to think I’m some sort of persnickety “Ace-in-the-hole”.😁

Chris

Last edited by PRR 5841

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