Postwar alco losing power on curves

I use CRC 2-26 to clean and lube up the pickup rollers.

Since it only looses power on curves, I wonder if you have a bad solder joint - it couldn't hurt to reheat them with a pencil tip.

That is not the original power truck for that engine. You could replace the front truck with one that has a pick-up assembly, they are readily available. Those early MPC (1970) motor trucks don't run well without a lot of tinkering.

The motor truck is a 8010-100 unit from the front of a NW switcher. Interesting retrofit.

I lubed the roller pickups and it ran like a dream... In a left-handed circle. I made it do a right-handed circle and it started losing power again. Maybe I need to replace the power truck.

The power truck has two traction tires on one side. I think they are dirtying up the track. I wonder if removing them might help my problem.

Replacing the traction tires could help, but I wonder, what track are you using? If it is like gargraves, the two outside rails are not connected and therefore you are only powering a single side. Traveling one direction the non traction tire wheels are powered, the other, the traction tire side is powered (poorly).

I'm using o-36 fastrack.

Tom M posted:

I'm using o-36 fastrack.

That has connected outer rails so there goes that theory...

The rollers are offset deliberately to compensate for the geared drive wheel. They are centered on the track

bmoran4 posted:

Tom M posted:

I'm using o-36 fastrack.

That has connected outer rails so there goes that theory...

Even with GarGraves the "other" rail is powered/bridged by every axle on the train.

In this case, it is likely that the traction tires are still causing the problem. A collector truck with rollers on the front will help with the electric issue, and checking that the chassis is getting a good ground from the front & rear trucks.

So I removed the traction tires, and... It runs like a dream. The only problem is now the engine sits a little off kilter. Oh whoa is me.

Your problem may be dirty collector rollers. Removing the traction tires would make the truck sit just a bit lower, increasing the pressure on them. (I know it sounds like a stretch).

The rollers pictured above do not look too clean to me.
I clean them by bending a Qtip and putting it through the roller to help keep it from rolling.
With your rollers, I'd start by scrubbing them with a Qtip wet with mineral spirits, followed by an abrasive cleaner. And then finish with a second cleaning using a Qtip wet with mineral sprints.
I would NOT lubricate the rollers. Wet lubricants attract dirt, and that style roller pickup is very sensitive to dirt.

Clean the drive wheel treads in a similar fashion.

Tom, some good suggestions here. I notice quite a bit of rust on the engine from your second underside photo. From your statement, that by removing the traction tires it is running better, leads me to agree with what ACDX Rob suggested about checking the ground from the chassis.

You should be getting ground current also from the front truck. I'd clean the wheels on the front truck also, as well as checking the frame itself, making sure their is no corrosion where the front truck inserts into the frame. It is easy enough to remove that front truck and also check the C-clip and the pin that inserts into the frame. Also check if there is any corrosion on the sheet metal inner frame of the front truck... everything there needs to be clean to insure a good ground from the wheels of that truck to the frame of the loco.

If you were getting a good ground from the non-powered collector truck, you shouldn't have had to remove the traction tires, at least by my experience.

The corrosion I see on the rear motor truck by your photo, would lead me to give the entire engine a good overall servicing and cleaning. If there is corrosion on places you can see, there's a good probability it's there in places you can't see.

pull the top off the motor,

clean comutator face and brushes.

The mods on this engine may not have been well thought out/done.

This is an eBay special and I am ignorant when it comes to postwar diesels. Maybe I need to cut my losses and start over from scratch.

A picture with the shell off might help, also what the front truck is. The original was the power pick-up, if it is still there and complete you can wire it to the system to help with powering.

any possibility that the track is dirty?

Bob C.

The track isn't dirty. Freshly cleaned with 99% alcohol and a magic eraser.

Based on the shell I figured I was getting postwar.

Based on the powered truck i think it may be mpc in postwar clothing.

The yellow wire that goes to the blob of tape is the only hot connection you have - I wonder what is hiding under the tape:

A) A nice, clean solder joint

B) A dirty, cold solder joint

C) Twisted wires

D) Corroded wires

E) @#%@^%#@

Loose twisted wires...

The front truck looks plastic(?) and so would be isolated unless there is a ground wire that is hidden. I also would check under that blob of tape! I think the E-unit lever was meant to stick up through the top of the shell, I am not sure if its present positioning could be causing a problem either mechanically or electrically.

midnightwrecking posted:

I think the E-unit lever was meant to stick up through the top of the shell, I am not sure if its present positioning could be causing a problem either mechanically or electrically.

midnight,

The shell is a transplant on the frame/motor. The E-unit seems correct for the frame and not the shell. This alone is not the cause of the issue.

Tom M posted:

Loose twisted wires...

Tom,

I would say it couldn't hurt to replace that connection with solder and heat shrink (tape will do if you don't have heat shrink or forgot to put it on first!)

On the early MPC Alco's the front truck does not ground.  Wrong E unit for the engine. The engine was obviously made from parts.

The best solution is replace the front truck with a postwar one, this will solve your problems, you will have both pick-up and ground.

Judging from the pictures it is a 3 position E unit and a 2 position motor ( dbl. wound field). It may not be wired right.

John

On the early MPC Alco's the front truck does not ground.  Wrong E unit for the engine. The engine was obviously made from parts.

Aren't early MPC Alco and SW-2 trucks constructed the same as a 1055 pilot truck? I thought they had a metal frame, just like the postwar ones do.

As for the mixture of parts: upgrading a locomotive with a two position e-unit to have a three position e-unit was documented by Lionel, and is generally not difficult to do. The locomotive is either wired properly or it's not.
This does bring to mind a handful of cases where the wire was broken inside the insulation and would make intermittent contact. That does not seem to be the case here, because it ran without its traction tires.

I have some new, old stock 8021-100 Alco motor trucks available, and can sell you one for $10 plus shipping.
These trucks come with the rollers (redesigned style) and knuckle. You would have to transfer the armature, brush plate, brushes, solder lugs, screws, and other miscellaneous hardware. Soldering would be required.

Then you'd have an engine with better collectors and the proper rear coupler.

The front truck on Toms engine is from a 8010 switcher which is plastic only. The early MPC 8020 and 8022 Santa Fe Alcos from 1970 and 1971 used leftover postwar front trucks which had the metal plate and a front coupler. Starting in 1972 the 8020 the front coupler was dropped from all Alco's there after, sans the premium Southern Pacific set from around 1975.   I will retract my statement that the Alco's didn't have the metal plate. The 8010 switcher did not and that's whats on Toms engine.

Postscript, The 8025 Canadian National Alco's from 1971 also had a front coupler.

I just checked two 100% original 8010 switchers with hollow roller pickups. The dummy truck has the metal plate. Never seen one without the metal plate. While these were natural colored, many of those plates were black in the modern era. I am not certain whether they used chemical blackening or paint. Here are the service manual pages on the truck.

OK, thanks CW, I stand corrected. So ground should not be the problem with Tom's engine.

yes, you need to pull the brush plate off the top of the motor and clean commutator face, brushes, pull

armature grease gears replace armature, oil armature spindle where it goes through brush plate.

Ive found a little TLC and oil, grease solves many slow moving problems

That doesn't explain the loco running perfect with the tires off.

Herr's the front truck you need.