USAT 44 Tonner

[Mohawk Valley]

Can anyone tell me what alternative motor block, complete with motor, wheels, gears etc fit this locomotive. When I bought the loco, it surged at slow speeds and taking the base plate off revealed four cracked gears. I’ve found a UK source of replacement gears for this locomotive, they are 3D printed in a stronger material that is less prone to cracking and fit remarkably well. They are available from James’ Train Parts, jamestrainparts@yahoo.co.uk
spent the afternoon fitting them…what a kerfuffle that is! Anyway, they surging is still there although not as pronounced, at slow speeds. At medium speeds it’s not really noticeable. I did turn the loco over and ran it at medium speed using the plungers as pickups. When full speed was applied, after a while I could see smoke coMing through the open holes in the baseplate. I have a suspicion the motor bearings might be worn. As the gears are sold as a replacement for the NW2, is the motor block or even the motor the same?
Cheers
Martin

 

[FatherMcD]

Can anyone tell me what alternative motor block, complete with motor, wheels, gears etc fit this locomotive. When I bought the loco, it surged at slow speeds and taking the base plate off revealed four cracked gears. I’ve found a UK source of replacement gears for this locomotive, they are 3D printed in a stronger material that is less prone to cracking and fit remarkably well. They are available from James’ Train Parts, jamestrainparts@yahoo.co.uk
spent the afternoon fitting them…what a kerfuffle that is! Anyway, they surging is still there although not as pronounced, at slow speeds. At medium speeds it’s not really noticeable. I did turn the loco over and ran it at medium speed using the plungers as pickups. When full speed was applied, after a while I could see smoke coMing through the open holes in the baseplate. I have a suspicion the motor bearings might be worn. As the gears are sold as a replacement for the NW2, is the motor block or even the motor the same?
Cheers
Martin

Not trying to insult you, but Greg Elmassian has some good tips at Diesel Motor Block Tips in relation to working on these motor blocks. It might not be a motor issue. The Motor block for the NW2 is an R22-12 and for the 44 tonner is R22-162 so not a direct replacement. There are a couple of sources for the R22-162 in the US, but you would have to search for a UK supplier. Motor only is an R22-163. Best of luck finding the parts!

 

[Mohawk Valley]

Not trying to insult you, but Greg Elmassian has some good tips at Diesel Motor Block Tips in relation to working on these motor blocks. It might not be a motor issue. The Motor block for the NW2 is an R22-12 and for the 44 tonner is R22-162 so not a direct replacement. There are a couple of sources for the R22-162 in the US, but you would have to search for a UK supplier. Motor only is an R22-163. Best of luck finding the parts!

Thanks Ken,
I’ve just been reading Greg’s pages, and they’re very informative. I’ve still got to find out the ‘elastic band’ method, refitting the axles were a right pain. Knowing the correct motor block number is a great help.
Cheers
Martin

 

[PhilP]

Running the whole loco through one set of plungers, and you get smoke?

So all the current is going though those greased-up springs, and those two thin spring wipers..

Are you really surprised something started smoking?


If you can run it from a supply with an ammeter in circuit, you will have a lot better idea of the health of the motors.

PhilP

 

[Mohawk Valley]

A very helpful reply, thanks a bundle Phil!

Now if you had have asked if I had cleaned up all the mucky grease, you would have got the answer that it was thoroughly cleaned before everything was put back together. Where lubrication was required, it was applied.
I don’t really see what difference it makes where I connect test wires, the plungers and wheels are where the electric picks up for the motor. Maybe I should have connected the test wires to the front couplers?

 

[PhilP]

Normally, you are picking up through eight wheels, and four skates. - 12 points of contact, and current pickup.

So all the current is going through 1/6 of the normal contacts. - So six-times the current, through that one path.

Perhaps I could have phrased it better?

PhilP

 

[Mohawk Valley]

Normally, you are picking up through eight wheels, and four skates. - 12 points of contact, and current pickup.

So all the current is going through 1/6 of the normal contacts. - So six-times the current, through that one path.

Perhaps I could have phrased it better?

PhilP

A much nicer reply, thank you. I understand what you are saying now.
Cheers
Martin

 

[Greg Elmassian]

OK, I revamped the 44 tonner page to reference:

rubber band method
disassembly
USAT motor blocks in general
cracked/split axle problems and repair

Look for the links in this updated page

(hint, on most USAT locos, the axles ride in brass bearings, but the 44 tonner has the axles riding in the plastic motor block casting. Excessive wear/lack of lubrication could wear this "bearing" and allow excessive axle play, which would exhibit itself as noise and surging... in this case only a new motor block will fix the issue, and they are only available as a complete assembly.

44 Tonner

Greg Elmassian web site on large scale trains and garden railroads, cigars, and computers

elmassian.com

 

[Mohawk Valley]

Thanks Greg, your site is extremely helpful. I haven’t had a chance to see what the elastic band method is yet, but I will.
so, the surging is a little better than it was with the 4 cracked gears, I might have to see if I can get a new motor block then…as rare as hen’s teeth I believe? Ah well, here’s to the big search!
Thanks and cheers
Martin

 

[Greg Elmassian]

Check the "play" on the axles on the motor block (disengaged from the sideframes)... I suspect this is your surging issue...

It could also be a worn motor with excessive thrust bearing wear (what controls the linear shaft movement in the motor)

I have 2 of them, they do not surge... does it surge the same on the level as on an upgrade or a downgrade?

 

[Mohawk Valley]

Hi Greg, thanks for the tips, I’ve looked at your exceedingly helpful pages about disassembling the motor block and axles. The elastic band truck is the only one I haven’t tried yet, I needed 4 hands to get them back together yesterday…
very helpful indeed!

I‘ve not long got in, so I will check the movement on the axles and motor over the next couple of days and get back to you. At the moment, I only have a short test track, I’m busy demolishing the old 0 gauge layout in the loft so I can continue with the G scale layout, so I can’t tell you how it runs on grades.

The squared off brass bearings are very similar to Atlas and Weaver bearings in their O gauge locomotives, so I’ve had plenty of practice in getting them in the right position.

Cheers

Martin

 

[Mohawk Valley]

Check the "play" on the axles on the motor block (disengaged from the sideframes)... I suspect this is your surging issue...

It could also be a worn motor with excessive thrust bearing wear (what controls the linear shaft movement in the motor)

I have 2 of them, they do not surge... does it surge the same on the level as on an upgrade or a downgrade?

Hi Greg,

Surge report.

ok, there is side to side movement on all axles bar one, which has no movement at all. The movement is not a lot and I would think this to be within parameters as there surely has to be some side to side movement to enable the wheels to go around curves. Of course I could be totally wrong!

Up and down movement is very small on two axles. The other axles are firmly held in their places in the motor block. There is no movement of the worm ends of the motor.

All these where completed with the side frames removed.

Whilst they were off, I took the opportunity clean out the bearings and remembering what you said about turning them 180 degrees, I did just that. Put everything back together and hey presto…it still surges at low speed.

I suspect I will have to bite the bullet and replace the motor blocks…should the side frames be replaced as well? Surely if the bearings are worn here, then the side frames need to be replaced as well.

Charles Ro are listing motor blocks for these in stock! I’ve emailed them to get a price to send to the UK, no reply as of yet.

Is the motor block for the S4 much bigger? Could it be adapted at all?

Cheers
Martin

 

[Greg Elmassian]

you did not answer:

I have 2 of them, they do not surge... does it surge the same on the level as on an upgrade or a downgrade?

any play in the "axle bearings" (i.e. the holes in the motor block where the axles come out) will increase surging.

Please answer the conditions under which it surges.

uphill with load
downhill with load
same 2 without load
on the flat with and without load (load = several cars)

turning the bearings at the axle tips just helps even out the wear, nothing to do with surging..

Greg

 

[Mohawk Valley]

you did not answer:

I have 2 of them, they do not surge... does it surge the same on the level as on an upgrade or a downgrade?

any play in the "axle bearings" (i.e. the holes in the motor block where the axles come out) will increase surging.

Please answer the conditions under which it surges.

uphill with load
downhill with load
same 2 without load
on the flat with and without load (load = several cars)

turning the bearings at the axle tips just helps even out the wear, nothing to do with surging..

Greg

Erm, just above your text is my answer to your previous questions.

 

[Mohawk Valley]

you did not answer:

I have 2 of them, they do not surge... does it surge the same on the level as on an upgrade or a downgrade?

any play in the "axle bearings" (i.e. the holes in the motor block where the axles come out) will increase surging.

Please answer the conditions under which it surges.

uphill with load
downhill with load
same 2 without load
on the flat with and without load (load = several cars)

turning the bearings at the axle tips just helps even out the wear, nothing to do with surging..

Greg

My fledgling layout is all level, being built in the loft and currently the only powered track I have I a short test track.

 

[Greg Elmassian]

If you are referring to post #11, so that just states you have a short, level test track.

So, is this is a loop, can you run continuously, or are you running a short length of track? If the latter, wait until you get a loop and let the loco settle in. You could also have other issues, track, transformer, etc.

Greg

 

[Mohawk Valley]

Hi Greg,
At the moment it’s just a very short length of straight track on my workbench. Everything else is running very well so I think the issue is with the engine. The track is clean, the transformer is working well and properly.
I will take your advice and see how things go.
Cheers
Martin

 

[Greg Elmassian]

Yeah, it's not necessarily enough to really understand what is going on.

If I was compelled to debug this, and it surged when running light, and a constant speed I'd look at excessive motor shaft movement, brush problems and perhaps a dirty commutator, especially between segments. The motor stuff would need disassembly of the motor, so I would only do that as a last resort.

Greg

 

[Mohawk Valley]

Yeah, it's not necessarily enough to really understand what is going on.

If I was compelled to debug this, and it surged when running light, and a constant speed I'd look at excessive motor shaft movement, brush problems and perhaps a dirty commutator, especially between segments. The motor stuff would need disassembly of the motor, so I would only do that as a last resort.

Greg

Thanks Greg,
At the moment it’s been pushed to the back of the queue pending further investigation. It is taking up valuable time where I should be working on more productive things like clearing all the O gauge track and replacing i with G scale track and overhead catenary up in the loft…I really need to get something running up there while the temperature is bearable…
Many thanks for your help, and I’m pleased I’ve found your very informative pages.
cheers

Martin

 

[Greg Elmassian]

Any time, and suggestions on clarifications or errors, or omissions are always welcome, it's public to help others, like some great people who helped me.