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Discussion Starter #1
Hello!!

Referencing my previous thread I have a 322 that just came out of restoration. It runs well, but I have a problem with it and thought I'd ding everyone here and see if anyone has any ideas.

Basically as it runs the motor is cutting out and the reverse unit is losing power for brief instants in time. If I leave the reversing unit in open then it will push the drum and stop the train. If I lock it in forward it will keep running, but the cutouts when the power is lost are audible and visible.

Other notes:

1. As far as I can determine both trucks are fully engaged with the road wheels on the track.
2. I replaced all the truck bushings and hardware, a short there is extremely unlikely, and in any case this isn't a short- the ammeter on the transformer goes to zero when it happens.
3. The track is approximately a 25' loop. On one half of the track the problem doesn't happen, (!!??) on the other half it does happen. I moved the track transformer connector from one side to the other and there was little if any change. The issue happens at many points on the loop, not just one or two.

What is throwing me for a loop is the track complication. I would think if it was a connectivity issue between the tender wheels and the track, or upwards from there to the reversing unit it would happen everywhere. I won't have time to dive in until later this afternoon or this evening, any help or insight will be greatly appreciated!

dce
 

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Since both the motor stops and the reverse unit coil loses power the problem is between the transformer and the internal connections to the tender pickups from the coil. The first thing I would do is double check the tender for adequate downward pressure from the brass axle wipers on all four axles.
Once those are confirmed good it is time to look at the half of the loop where the engine does not run well. First try some other engines and see if they do the same thing, if so definitely a track problem. If not it still could be loose or oxidized track pins. When the engine stops push on the track near the closest joints and see if that affects the power to the engine. I am assuming there are no turnouts in this loop.
Over decades of assembling layouts with Gilbert track and then chasing bad or high resistance track joints I changed how I assemble the track. First I wipe each pin with some 400 grit paper to assure it is clean with no oxidation. Second I verify all the track joints are tight. Third, before final assembly I put a small amount of anti oxidant conductive grease on every track pin. Fourth, no turnouts are used w/o disassembly to clean and polish the electrical contacts and wipers inside. Fifth, all 696 and 707 track clips are carefully tightened prior to use using long nose pliers. The track flanges are rubbed with the 400 grit paper where the track clips will go to assure best conductivity. The conductive grease is also used on those spots on the rail flanges prior to installing the 696's and 707's.
When assembling the track make sure the rails butt up to each other and none are bent. Also make sure there are no high spots at the track joints. Following these track assembly steps has resulted in flawless operation on Gilbert track.
 

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Discussion Starter #3
Thanks for the help- I've got a quick update before I have to return to more prosaic matters.

I checked the contacts and you were right- the last one (4 of 4) was not firmly seated against the wheel axle. Removed the wheel set and adjusted accordingly. Now all four have goot pressure between the axle and the copper contact pad. So the good news is it made the locomotive noticeably quicker (I'm running it alone right now) which should translate to less stress when pulling stuff. The bad news is the droppages are still happening, albeit with less impact now as the train is moving faster. I've noticed that they happen pretty much at the same places on the loop which leads me to conclude that it is something between track junctions and the trucks that is causing one truck to be isolated from the circuit for a split second. Because I had to replace both trucks I have used small machine screws with locknuts to hold them on and I am thinking that I have done something in that installation that is causing this. The trucks are fairly firmly attached, with little back and forth or gimballing play and basically no headspace between the top of the truck and the washer/chassis plate.

As an easy first start I am going to back off the nuts and make the trucks really loose and see what happens. That will take only a couple of minutes and will hopefully give me a direction to go from there. More soon- and thank you for the help- I think it got me started in the right direction!!

dce
 

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Agree with flyernut. Attach the trucks with the correct parts, they are readily available.
 
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