N scale brass Allegheny: weak motor?

[simsuper80]

Hopefully someone here knows a thing or two about these engines. I have a key imports Allegheny locomotive, and it's pulling power is very underwhelming. Even just around 15 cars is enough to slow it down significantly. Any longer and it struggles to pull the consist.

The reason I think it's the motor is because normally, when I hold a locomotive back (grab the train with my fingers) the wheels will Just keep on spinning. The bachmann EM1, despite having traction tires will do this. When I do this with my Allegheny, the wheels stop spinning, the locomotive does not slip at all (Well, barely). I am wondering if a motor replacement would solve this issue, as it has got more than enough weight to pull a longer train. It's heavier than the EM1, but the pulling power comes nowhere near that of the bachmann model.

[woodone]

Do not know anything about these locomotives. Having said that I do not think changing you motor will make it pull any more cars.
You stated that when you would hold it with your fingers the drivers would slip. That would mean there is not enough weight/or the balance of loco is way off. Maybe more weight would help. I really do not think a replacement motor will solve the pulling power of the locomotive. I would try placing some weight on the loco with tape/or other means to see if that would help.

[Jesse6669]

I think you misunderstood.  He said with other locomotives the drivers slip, but with the Allegheny the drivers stop (so maybe it has a weak motor).

[robert3985]

First, you need to determine for sure if the motor is actually stopping. Could be worm on the motor's shaft is loose and it is stopping, but the motor is still spinning, or something similar in the gear train, such as a cracked gear on the driving wheelset's axle, which was a common problem on some brass engines if it was made from Nylon.

If it hasn't been run in a long time, then it will benefit from just running for a while all by itself, which will loosen up the oils/grease that are on brass engines, as most drivers are mounted in bronze "friction bearings" which slide up and down in matching slots in the frame...and the oil/grease that's put on them at the factory has a tendency to harden up after the locomotive sits for a long time...like years.  You can help loosen things up by heating the drivetrain up by blowing on it with a hairdryer set on low for a couple of minutes.

Then, maybe something is binding with all those drivers going round and round...which will imitate a motor being underpowered.  I've never had a Key Import locomotive have a bad motor, or an "underpowered" one...so, my thought process is rejecting the possibility and saying to me that the problem is most likely somewhere else in the drivetrain, with a gear problem or binding.

But, I've been known to be wrong.

Cheerio!
Bob Gilmore

[u18b]

I agree with Bob.    That particular loco has a lot of u-joints in it.   If even one is failing, pulling power will be greatly reduced.

Pulling the shell and studying the internals is the first step.

[Rasputen]

I have a couple of them.  It sounds like something is slipping, or that some of the grease has thickened up.  Normally these are outstanding pullers.

[peteski]

Not familiar with this loco, but if it uses silicone tubing as universal coupling between motor and worm shaft, these can slip when oil gets onto them.

Without even taking the loco apart it should be easy to determine if the motor stalls, or if there is a slippage.

Power up the loco about half throttle or more, then hold it such a way that the wheels stop turning (stall it).  If you can still hear the motor spinning (running), then there is slippage in the mechanism.  If the loco makes no noise (motor is stalled), then there is a problem with the motor or some electrical issue.

[woodone]

Yes , it seams like I missed the fact he was holding the loco and no slipping of the drivers.
Like others I would be looking for cracked gears / or u-joints.

[randgust]

Mark Peterson (Spookshow) has put warning labels on tearing these apart:
http://www.spookshow.net/loco/key2666.html

Not that you can't do it, but be prepared.

[simsuper80]

Not familiar with this loco, but if it uses silicone tubing as universal coupling between motor and worm shaft, these can slip when oil gets onto them.

Without even taking the loco apart it should be easy to determine if the motor stalls, or if there is a slippage.

Power up the loco about half throttle or more, then hold it such a way that the wheels stop turning (stall it).  If you can still hear the motor spinning (running), then there is slippage in the mechanism.  If the loco makes no noise (motor is stalled), then there is a problem with the motor or some electrical issue.

Here is a short video showing what happens. And this is max throttle by the way.

https://www.dropbox.com/s/0fy3fh1vq3ndr7d/20220125_204422.mp4?dl=0

[mmagliaro]

 
The thing that jumps out at me is that there is clearly a bind in the driver rotation at the same place
on every rotation (in fact, it seems to be at two places: when the crank is at the top and when it is at the bottom of rotation).

Since the motor turns many times for each driver rotation, that means that a slipping coupling, weak motor, or gear problem is not causing that stall in every rotation.   I think you have a bind in the rods or valve gear somewhere.
But in addition, I *think* I still hear the motor running each time the drivers stop, which makes me think that the drivers bind,
and THEN that causes a slip in a coupling somewhere.  But both problems need to be fixed.
..
Backing up from all that, can you get that boiler shell off so we can see what the drive shafts and couplings are doing
while you are running it on that test track?

[u18b]

There may be many problems.   It looks to me like the drivers are out of alignment.
Either a quartering issue or gear/tooth placement issue.



A more direct side-on shot of both sides might be helpful.

[simsuper80]

The thing that jumps out at me is that there is clearly a bind in the driver rotation at the same place
on every rotation (in fact, it seems to be at two places: when the crank is at the top and when it is at the bottom of rotation).

Since the motor turns many times for each driver rotation, that means that a slipping coupling, weak motor, or gear problem is not causing that stall in every rotation.   I think you have a bind in the rods or valve gear somewhere.
But in addition, I *think* I still hear the motor running each time the drivers stop, which makes me think that the drivers bind,
and THEN that causes a slip in a coupling somewhere.  But both problems need to be fixed.
..
Backing up from all that, can you get that boiler shell off so we can see what the drive shafts and couplings are doing
while you are running it on that test track?

The most I have ever done was taking the front set of drivers off. Never the boiler. I can try, but I just hope that I can put the thing back together again 😆

[robert3985]

The most I have ever done was taking the front set of drivers off. Never the boiler. I can try, but I just hope that I can put the thing back together again 😆

Take photos as you go. Too many photos is much better than too few.  Usually re-assembly is just a matter of getting the sequence correct, but in the opposite order.  Also, have some small, shallow containers available to put your small parts in in an orderly fashion.

And lastly, don't put off reassembly.  Put it back together when you get the problem solved.

Cheerio!
Bob Gilmore

[mmagliaro]

simsuper80:  I hear you.  I repaired one of these for somebody once, and I do recall it being tricky to get back together.
It's been long enough that I cannot remember the details.
But Mark (spookshow)'s review page has a description of the process at the very bottom of his review page here:
http://www.spookshow.net/loco/key2666.html