Model Power Mogul Stalling

[MK]

Damn!  And I was just about to order one of these (or the 4-4-0) since MBK is having free shipping.  One of my club member has a 4-4-0 (MRC) and it runs beautiful and the sound is not that bad at all.  But I like the looks of the 2-6-0 better.  Maybe I'll stick with a 4-4-0.

[Mindheim]

Good input thanks to all.  Let me dig into the ammeter suggestion.  Also, I want to add that I have THREE of these units and the problem is the same with all of them.  I want to be careful not to disparage this product as I'd still recommend it due to the smooth slow speed running, low cost, and nice details.

[mmagliaro]

Oh!  One more thing.  I know you said you disassembled and cleaned "everything"... but did you clean INSIDE the
cups of the pickup strips in the tender trucks, where the points of the wheelsets ride?  This is common contact problem point, even on Kato tender trucks.  You might dig a toothpick around in those cups with some alcohol, and make sure they are very clean.

In fact, I've got a Kato Mikado that for some reason seems to have axle cups that get dirty or blackened more than any other one I have ever had, and I have to periodically clean those cups out to keep it running well.

[Maletrain]

Re that Kato Mike with the axle pickups that keep getting blackened:  Try cleaning them with something other than alcohol.  Try mineral spirits.  The difference is that the "non-polar" molecules in mineral spirits are better at protecting the conducting surfaces from arcing than the "polar" molecules in alcohol.  Let us know if that helps.

[brokemoto]

did you clean INSIDE the cups of the pickup strips in the tender trucks, where the points of the wheelsets ride?  This is common contact problem point, even on Kato tender trucks.  You might dig a toothpick around in those cups with some alcohol, and make sure they are very clean.

This is EXCELLENT advice.  I have seen this on tender trucks more than a few times.  In addition, it happens even more frequently on the trucks of diseasels that use this type of pick-up (LL SWs,, for one).  You have the added WHAMMY of lubrication that can find its way in there and not only compromise the conductivity on its own, but also attracting dirt which makes it even worse.

The major enemies of All Things N Scale are:

1.   Dirt
2.   Dirt
3.   Dirt
4.   Dirt
5.   Quality control
6.   Overlubrication which attracts MORE Dirt
7.   Dirt
8.   Misuse
9.   Dirt
10. Poor construction methods

Oh, did I mention Dirt, yet?

[MK]

Oh!  One more thing.  I know you said you disassembled and cleaned "everything"... but did you clean INSIDE the
cups of the pickup strips in the tender trucks, where the points of the wheelsets ride?  This is common contact problem point, even on Kato tender trucks.  You might dig a toothpick around in those cups with some alcohol, and make sure they are very clean.

In fact, I've got a Kato Mikado that for some reason seems to have axle cups that get dirty or blackened more than any other one I have ever had, and I have to periodically clean those cups out to keep it running well.

Re that Kato Mike with the axle pickups that keep getting blackened:  Try cleaning them with something other than alcohol.  Try mineral spirits.  The difference is that the "non-polar" molecules in mineral spirits are better at protecting the conducting surfaces from arcing than the "polar" molecules in alcohol.  Let us know if that helps.

Maybe DeOxit can help here?

[strummer]

This is EXCELLENT advice.  I have seen this on tender trucks more than a few times.  In addition, it happens even more frequently on the trucks of diseasels that use this type of pick-up (LL SWs,, for one).  You have the added WHAMMY of lubrication that can find its way in there and not only compromise the conductivity on its own, but also attracting dirt which makes it even worse.

The major enemies of All Things N Scale are:

1.   Dirt
2.   Dirt
3.   Dirt
4.   Dirt
5.   Quality control
6.   Overlubrication which attracts MORE Dirt
7.   Dirt
8.   Misuse
9.   Dirt
10. Poor construction methods

Oh, did I mention Dirt, yet?

See? This is why I love the RW... 

Mark in Oregon

[Mindheim]

I can lift the loco up so only the tender wheels are on the track and the drivers will turn. Likewise I can lift the tender off the track and it will run.  More running today on clean straight track.  It stalled and the light went off.  A few seconds later, without touching it, the light came on and it began running again.  Also, the longer I run it/test it the better it runs and the more the problem subsides as it warms up, almost entirely.

[Lemosteam]

I can lift the loco up so only the tender wheels are on the track and the drivers will turn. Likewise I can lift the tender off the track and it will run.  More running today on clean straight track.  It stalled and the light went off.  A few seconds later, without touching it, the light came on and it began running again.  Also, the longer I run it/test it the better it runs and the more the problem subsides as it warms up, almost entirely.

This comment leads me to wonder if temperature expansion may be leading to this?  Not being familiar with this particular locomotive, are there any "squeeze fit" or interference fit electrical connections inside where as the motor heats up the frame, and so the contact points as well, enough where the contacts become more conductive as the loco warms up and the converse if the loco cools down?

[mmagliaro]

I can lift the loco up so only the tender wheels are on the track and the drivers will turn. Likewise I can lift the tender off the track and it will run.  More running today on clean straight track.  It stalled and the light went off.  A few seconds later, without touching it, the light came on and it began running again.  Also, the longer I run it/test it the better it runs and the more the problem subsides as it warms up, almost entirely.

This comment leads me to wonder if temperature expansion may be leading to this?  Not being familiar with this particular locomotive, are there any "squeeze fit" or interference fit electrical connections inside where as the motor heats up the frame, and so the contact points as well, enough where the contacts become more conductive as the loco warms up and the converse if the loco cools down?

This behavior is *also* something I experience when tender truck axle cups are dirty.  Just because the engine runs when you hold just tender on the track doesn't mean there isn't a pickup problem in the tender.  This is an intermittent problem.  On Kato Mikados, when the axle cups are dirty, it often gets better after the engine runs for a few minutes because the axle points turn and rub in those cups and make a "clean spot".  But then after it sits for a while, the problem comes back because the dirt isn't gone; it has only moved around in there.  All I'm saying is that this is a relatively easy thing to clean, and then you can continue your experiments to see if makes any difference.

Oh, and the headlight going out and then coming on when it starts to move convinces me that this is a pickup problem rather than a mechanical jam.

[Chris333]

My only DCC N scale loco was a Walthers 2-8-8-2 with 12 wheel tender. That is a lot of wheels picking up power. But it still needed perfect track to run. Some sound decoders are just finicky with voltage.

[daniel_leavitt2000]

This is an interesting thread. Everyone pretty much covered the main issues I have had with mine:

1. Improving pickup on the first generation versions.
2. Dirt pickup in axle cups.
3. Out of quarter drivers.

I wrote an article years ago on how to add TT drivers to MP engines. This is a lot harder than others due to the inane wiring these things have. These will all eventually fall out of quarter. It is just an inherent design flaw. To fix this, I have made small "sipes" on the plastic wheel where it connects to the axle, and then securing it with a VERY small amount of red thread-locker Loctite. The red version has a lower break threshold than other versions and allows to wheel to be removed if necessary. It's used mostly to secure crowns to winding stems on watches.

The axle pickups on the MRC versions have their own issues. The metal is not the standard bronze that others use but this blackened chromish colored material that seems to be more susceptible to dirt pickup. You can clean these and burnish them by tossing a toothpick or BBQ skewer in a Dremel and running it for a few seconds against the inside of the cups. Axle ends can be cleaned by twisting the wheel-sets in your fingers against an eraser.

What decoders are you using? You might be able to mitigate the stalling by adjusting the kick start voltage and rate.

[peteski]

The axle pickups on the MRC versions have their own issues. The metal is not the standard bronze that others use but this blackened chromish colored material that seems to be more susceptible to dirt pickup.

I would bet you dollars to donuts that what you see is plating.  If you were to grind into those plates they would be standard bronze, phosphor bronze, or brass.  But to your point, until that plating wears down onsinde the cups, it can be problematic.

What decoders are you using? You might be able to mitigate the stalling by adjusting the kick start voltage and rate.

Since this is MRC loco, the factory-installed MRC decoder.

DeOxit is petroleum-based, so it should work as well as mineral spirits, Atlas Conducta-lube, or even oil.

[MK]

... then securing it with a VERY small amount of red thread-locker Loctite. The red version has a lower break threshold than other versions and allows to wheel to be removed if necessary. It's used mostly to secure crowns to winding stems on watches.

I think you meant Blue LocTite.  The red stuff is practically permanent.

[Hansel]

For my steam locos, Model Power and Athearn, I use a wire brush on my Dremel to keep the tender wheels clean and use the Trix loco brush with the power which goes to the bristles for the drivers.  Makes a big difference in electrical pickup.  I have also converted all of my tenders to all wheel pickup using a Bachmann tender.