Lionel PW 726 Stall Problem......need some ideas

A eunit dropping out can be caused by a loss of power or a momentary short circuit, which causes a loss of power. You might want to install a high speed circuit breaker, like a post war 91, to see if you can determine which issue might be causing your problem. 

   I would help it through at just under stall speed and watch close for roller issues.

Maybe clean all the turnout rails real well. Scotchbrite them.

You never mentioned which turnouts you use.

The engine may be bouncing over your 027 switches.
Without looking, I think the postwar Lionel 726 has wide rollers. They might be getting lifted from the center rail by other parts of the switches as the engine goes through the switch.

I suggest you make certain the rails on the offending switches are clean, and that nothing is bent.

ROGER1 posted:

 4. I do have a capacitor system on my switches (PW1122 switches ) that eliminates the buzz and sometimes I do have issues with some engines. But I have a power cutoff to the cap system and when I cut the power, the engine still intermittently stalled.

Have you noticed whether this is happening with 1122... or 1122E switches? On the original 1122 switches(one year only) there were issues with getting good ground to some locomotives, and if you are using fiber pins with 1122 switches, this makes it even worse. The 1122E switches require fiber pins, the 1122 does not.

In answer to the above 3 responses.....much appreciated, though.

David......I DO use 91 breakers. They are incredibly fast. I've got 5 amp thermals as "backups" (only because they were on there first). I've got a toggle switch that can take the 91s out of the loop because some engines can cause "nuisance trips". I toggled both ways with this engine and the stalling happened irrespective. So, I don't think it's a short.

Adriatic.......they are PW 1122E switches.  I had emory clothed the rails of the two switches.  Didn't seem to help. It's hard to look under that engine when it's moving, but I did not see sparking. Sometimes, you can see the roller bridge the frog and a side rail to cause a short (which instantly causes a short, which instantly trips a 91). In those cases, I put a dab of Super Glue on the spot (after having put a piece of electrical tape to locate it). But it doesn't appear to be the case here as explained above

CW......yes, the rollers are wide, causing me to suspect the "bridging". But when I swapped out the roller assembly with one from a 736 last nite, it still stalled.

Can the "melt spot" on the drum of the e-unit cause this?  Not alot of options left , I think

Roger

Rob,

Sorry......I didn't see your response as I was typing the above. In the paragraph to Adriatic, I mentioned the 1122E designation.

Ok, let's think about this.  When it goes from forward to neutral that means the e-unit coil lost power momentarily and got it back so it rotated the drum (it is unlikely a melt spot will cause this).  Does the engine roll much further after it loses power?  Turn power off and tilt the engine sideways, where are the pickup rollers when the engine stops?  Photos will help with where the rollers are located.  Does it only lose power on this one switch or other places?  If the engine is running slow enough that it doesn't roll very far then where the rollers are located on the switch is where the problem is at.

Gene Anstine

Gene,

I have been trying to locate the spot. When you use 91 breakers, you end up doing that alot because it doesn't take much to trip them. But this engine rolls quite a bit after the power interruption, so I kind of have to do it by hand.....and then I can't get it to lose the power.  A quandry. 

I did notice that the swivel plate lifts as the engine passes over one of the problematic switches. I put a shim underneath the swivel and it still would stall. 

It may even be stalling on the UCS track in front of one of the switches, but I can't say for sure on that one. Haven't seen it do it there for awhile. 

Might have missed this information. Does it do the same thing running thru the switch in reverse? How about coming from the opposite direction? If you lock it in forward and run thru slowly does it stop as if it lost power?

Roger - this is what happened to me - very similar circumstances - engine rolled over the switch and stopped in neutral - the video shows that I found a loose frog and rivet. I had to remove the back from the switch to tighten, but when done, the problem totally went away.

It sounds like you may have already addressed this, but I thought a video is worth 10k words, so take a peek 

George

You might be onto something there, George. I do have a loose rivet on the swivel. It's always been loose and it causes the outer rail of the frog to lift. I mentioned earlier that I put a shim underneath to see if it helped. It didn't, but I didn't use a thick shim and, the rivet that is loose is not on the frog......it's on the swivel itself. The other nite I was going to bang the rivet down with a nail set to hopefully crush the back side of the rivet tighter. But I'm not exactly sure what's under that swivel. When I do my "cap mod", I don't take off the bottom of the switch.......I drill a window in the base with my Dremel because I've done so many of these that I know exactly where I have to splice in on the underside of the switch. Most times, if a switch is not working out for me.....rough ride, shorts etc.....and I can't repair it without doing a major dismantle......I Ebay another one. Cheap.

I'm going to take a look at that rivet situation later and see if I can tighten it up.  But it's very weird.  There are two rollers on this engine and they are widely spaced. What are the chances that both lose contact at the same time?   And......when I put the collector assembly from one of my 736s on there.....same thing happened. But............I can run both of those 736s through those two switches and they don't stall. Has to be something in the 26 itself. 

Roger

The 1122s are O27 switches - the 726/736 are O engines. Generally, they do navigate O27 ok. However, I have found that the eccentric crank can collide with the switch mechanism lifting the engine up and making navigation around the switch difficult.

BMORAN,

I don't run my bigger engines through the turnout. Only my smaller PW and modern engines are capable of the s turns. One of the biggest regrets I have after getting back into my trains 12 years ago, was sticking with the 027 switches. Big mistake on alot of levels. Changing my layout now would be a royal PITA. So, I deal with it. 

This issue I'm having with this engine is on the straight section of both switches. One of them is much worse with it than the other. But it's only happening with this engine. 

ROGER1 posted:

You might be onto something there, George. I do have a loose rivet on the swivel...…...The other nite I was going to bang the rivet down with a nail set to hopefully crush the back side of the rivet tighter. 

I'm fairly certain that won't work, the whole affair will just flex and dent since there's no solid backing to support a blow.

Most times, if a switch is not working out for me.....rough ride, shorts etc.....and I can't repair it without doing a major dismantle......I Ebay another one. Cheap.

I hear ya! Price vs. effort is a worthwhile consideration. The only reason I went to the trouble was because I had a bunch of them that I got REAALLLY cheap and wanted to learn how to repair and what's inside.

There are two rollers on this engine and they are widely spaced. What are the chances that both lose contact at the same time?

My technique is to get down at track level, grip the engine on both ends, use my left foot to hit the power, then provide "controlled motion" over the switch, back & forth, side to side until it shorts or opens. Usually you can eyeball the exact spot that way. But I'm guessing you have probably done similar already. Some aren't so easy!

George,

Yes.....I've got a very narrow LED flashlight that enables me to see under. But it's very awkward trying to lay across the edge of the layout to do it. Stuff gets smashed. LOL. As for that rivet....I pried up the swivel just a touch and I could see that there's a cut out under there that the bottom rivet head moves along. Whacking it will bend the groove. So, here's what I'm going to do. I opened up my spare switch boxes and found 2 right hand ones that I already wired and have good snap. And two that I haven't touched. So, I'm going to swap one out.   It could potentially open a can of worms. I settled on this group to minimize problems with other engines. So, I'm sure if this solves it for the 726, I'll get nuisance trips  on my 91s with other engines.   It never ends!

I just swapped out one of the switches. No different.  I'm also finding that if I push the engine in neutral over a UCS track or a switch, it moves into forward or reverse suddenly. Must be losing power somehow.  I locked out the e-unit in forward and it did not stall anyplace.   It's also starting to stall at times around one of my turns on uninterrupted track. Can it be the e-unit itself?       It's only happening with this engine and it appears to be a recent phenomenon. I don't run it often, but it never did this before.

Roger

When it moves into forward or reverse suddenly, does the headlight blink (it might be very quick)?
Try locking the e-unit into neutral and look for the blink. Then observe where the collector rollers are located.

You could have a dead roller.
I don't have any reference materials handy, so I am uncertain whether the collector rollers on your engine rotate on axles/rivets, or had nubs on the ends.
If they rotate on axles, I have run across pieces that had so much crud in the center of the roller that no electricity was being conducted. I had to physically remove the roller to resolve the issue. Either clean out the hole with a drill bit, followed by a pipe cleaner with your favorite cleaner (I use mineral spirits), or replace it.
Same goes for the pin or rivet: clean it or replace it.

I suppose you could have the same issue where the arm is articulated at the base, but I have not seen this problem.

CW,

I've got nubs on mine. I removed them yesterday and cleaned the nubs and Dremeled the roller (brush). Didn't effect it. I also hit the spring and spring axle with contact cleaner. 

I'll try that blink test a bit later. Need a break. 

Could it be the e-unit?

CW,

As I don't have replacement rivets for the springs, I may solder on a small wire from the arm to the collector frame and see it there's an improvement.  Although I doubt it since I already tried swapping out the collector assembly for one of my 736s.

No blink when it stops with the e-unit unlocked. I'll try it later locked

Could it be the e-unit?

If there isn't any blink of the headlight, then the e-unit is a possibility. Is the switch handle loose? are the solder joints from the e-unit coil to the terminals good?

But if it was the e-unit, the problem wouldn't be likely to always occur at the same few places.

CW,

The worm turns.........

The lever on the e-unit is tight. It wasn't always that way. Last year, I put a sliver of styrene behind the masonite. Very tight now.     I resoldered the solder points on the unit a couple of nights ago.     

The stalling on that curve is a new thing. All of the stalling, no matter where it occurs, is intermittent. If the engine is going fast, it's not likely to stall, which made me think it was rollers. But swapping out the roller assembly didn't fix it. 

There must be a loose wire someplace.....          But here's another weird thing. I shouldn't get continuity between the short arm of the switch (straight portion) and the next piece of track (inside rail) because there's an insulated pin there. Some switches I do, some I don't in that spot and it seems to change. I have a feeling it's due to the wiring of the capacitor/fixed voltage system. It doesn't seem to effect other engines.

Roger

How is your track for dips? Some times the pilot can get bent or sag lower than specs and ground out on humps or dips in the track. Also it wouldn't hurt to take a gander at the pilot truck.

MidnightWrecking,

The pilot didn't seem to be hitting anything. I've had other engines with cowcatchers that bottom out on frog rails. I did think the rear truck was an issue, so I removed it and ran it again. No change.

Well, whatever is wrong with this engine, it's getting worse. It's stalling now in lots of places on the loop (not just switches). It does not seem to occur when going fast, but at slow speeds it's not going to complete a single loop without stalling now. 

No blinking of the lamp, but something is making that e-unit cycle. Bad coil in the e-unit?

Roger

IS the headlight illuminated when you get no circuit between the e-unit lever and the track?
If you move the test point to a different section of track, is the circuit still open?

Can you temporarily connect a jumper between the e-unit ground terminal, and a ground on the chassis, bypassing the lever?

CW,

A question about what you wrote above.   Do you mean when the engine moves to an area where the e-unit cycles to neutral, is the lamp illuminated?  And if I push the engine off the offending spot, does the lamp change?

If you have a general power pickup problem, the light will blink at the exact same time the e-unit cycles. The off time may be very very brief, so you would have to watch very carefully. It helps to move the engine as slowly as possible.

The light will not go out and stay off unless the e-unit is also off. So no, if the e-unit has cycled, the power was restored and the lamp will be lit.

You may find a spot at which both the light is off and the e-unit is not activated, even though there is power to the track. If so, then you can determine whether it is a problem with the center rail pickup or the outside rail.

In my experience, problems with outside rail pickup are more common in diesels, and small steamers (basically scouts). That doesn't mean those problems cannot occur in larger engines. But I guess they'd be rare.

CW,

I'll check the lamp again later. With the shell off, I had to tape it down to ground it.   I just opened the brush plate to check the brushes (one of the only things I hadn't done, I think). They looked very good, but I did clean out the brush tubes. No change. 

One other thing I noticed that is a bit confounding. Slowing the engine before it enters the problem areas increases the likelihood of a stall. But if I run it at that slower speed (instead of throttling down to that speed), it's not likely to stall. Coincidence, probably. 

Normally, these kinds of things have been relatively easy to track down. Not this one. 

Here is a THEORY to explain that behavior.
When you run at a consistent speed, the rear wheels are going to be pushed to one side by the action of the worm gear.
If you are slowing down in the problem area, the sideways pressure exerted on the axle may be reduced or even reversed, shifting the rear drive wheels to the other side.
If there is significant play in the rear axle, the position of the whole chassis on the track would shift slightly, and might make a difference.

Again, this is just THEORY.

Theory or proven fact......I'm open to anything at this point. I just checked the play in the rear wheels. A full 1/16 inch. That's more than both my 736s and most of my steamers, but my childhood 2035 appears to have more and that runs like silk. But that engine doesn't have a worm.

But that engine doesn't have a worm.

Which means there is nothing pushing the drive wheels to one side or the other.

Does 1/16 seem excessive? Maybe  I could get a shim in there.

Just a thought, are you running the engine alone or with its tender? I had a bad pick up wire on a tender short out intermittently, but happened more on curves and turnouts. I thought it was the track, then the engine, then finally found the shorting wire in the tender. You probably already checked this, but it crossed my mind when reading the post. Good luck!

JD,

Initially, I was running a consist with the tender. Did all the roller work that way. But when I suspected a rear truck issue, I removed the truck and have been running the engine by itself (because the drawbar is gone) and the issue continued.  Whatever is causing it, has gotten worse. 

Thanks!

ROGER1 posted:

...I removed the truck and have been running the engine by itself (because the drawbar is gone) and the issue continued.  Whatever is causing it, has gotten worse...

Hmmmmm...  a poor ground/common connection to the chassis will certainly be exacerbated with the absence of the rear 2 axles / 4 wheels.

Rob,

I'll reinstall it and see what happens. It seemed to do it with truck on and truck off. But the fact that it now occasionally stalls on turns is new. I'll report back on that. Thanks

Roger

Does 1/16 seem excessive? Maybe  I could get a shim in there.

I go by whether anything is rubbing: the backs of the wheels against the chassis or the worm gear rubbing against the sides of the well.
I guess there could be issues with the side rods rubbing too.

I would recommend reinstalling the rear wheels, then add the tender, but I would remove the tender shell and run jumper wires from the tender to the engine - one ground, one center rail - this of course assumes you have a center contact roller on the tender. If the problem persists, it would seem to point to the e-unit as the culprit. If you're familiar with rebuilding e-units, I would do that next. Actually, I probably would have done that a while back just to get that bugger out of the equation. In fact, if I had a different e-unit lying about, I would substitute it in as a quick check.

CW,

Well.......we finally found something that IS wrong with it. Whether it is causing the stall is another story. I looked to see if the wheels were rubbing. I did a cursory check of that the other day and didn't notice anything amiss. But there is. One of the rear wheels can slide over and is contacting the wheel in front of it. And was worn away a line around the base of the flange. Not major, but under my magnifier, it's clear. 

George,

I normally do rebuild bad e-units, but I'm all out of parts. I was thinking of jerry rigging a spare e-unit in there. Problem is.....it's a bottom mounted lever. I'd have to elevate it and then ground it with an alligator.    I will try the tender jumpers later this afternoon and get back to you. As for the wheels.....I don't have a gear puller or a press. If I were to take the slack out of those rear wheels, I'd have to  use my vise.....which I've done before, but is iffy.

What constitutes an E-unit rebuild?
For the e-unit to cycle, it has to be loosing power.
It's not a fast, intermittent short because Roger uses #91 breakers.

In order for an e-unit rebuild to have any effect, I think he'd have to break down the top section to tighten or remove/reinstall the e-unit lever, and resolder the wires from the e-unit coil to the terminals.

Here is another thought:
On your 726, are the smoke unit wires attached to the e-unit hot terminal or to the terminal coming up from the collector?
If they are soldered to the terminal coming up from the collector, then you could have a bad wire or loose connection from the collector terminal to the e-unit. I did not think of this before because most locos have the headlight and smoke unit wired to the e-unit terminal.
And if everything is wired to the e-unit terminal, you could have a good connection between the wires, but a poor connection to the terminal itself.
In either of these scenarios, the e-unit cycling problem should be random, not happening in specific places.

CW,

The lamp and smoke are connected to the roller terminal (which I desoldered). I'll wire them up to the e-unit and see if there's a difference.

C W Burfle posted:

For the e-unit to cycle, it has to be loosing power.
Agreed, either losing power or a short, and I think the consensus is there's no short

 

In order for an e-unit rebuild to have any effect, I think he'd have to break down the top section to tighten or remove/reinstall the e-unit lever, and resolder the wires from the e-unit coil to the terminals.

Which is why I prefer swapping instead of repairing - it gets rid of variables like the possibility that there's an intermittent connection being jostled every time the engine bounces over a specific switch or bounces side-to-side in a turn. Granted, I'm stretching on this theory, but I have actually had it occur. E-unit ground leads are either soldered to the e-unit frame (rare) or spot welded in places where you cannot see them. And a hot lead can appear for all the world to have a good solder connection, yet be intermittent - had that about a month ago.

 

In either of these scenarios, the e-unit cycling problem should be random, not happening in specific places.

I like the bouncing theory!  That could explain why it's not random

This may not fix anything, but at least you will have eliminated the e-unit as a root cause. I would use double sided tape or tye wraps to hold and old working e-unit in there as a substitute.

E-unit ground leads are either soldered to the e-unit frame (rare) or spot welded in places where you cannot see them.

Don't think I've seen this. The wires from the e-unit coil are soldered to the terminals on the fiber plate.
What parts of an E-unit are soldered or welded? The only exception might be the e-units that don't have a lever.

And a hot lead can appear for all the world to have a good solder connection, yet be intermittent - had that about a month ago.

I've seen that too.

Hey Guys,

I think we've got a wiff of success here (finger's crossed). I spent the last hour and a half rewiring the wires to the lamp, smoke, rollers, and e-unit connections. Fired it back up and......no change. Of course.               How many possibilities can there be?     But then I remembered I hadn't  done the test that George suggested.....running jumpers from an open tender. I ran tender rollers to e-unit incoming and frame to frame. Fired it up and......it didn't stall........anyplace. I ran it for about 5 minutes, varying the speed and it went smoothly through all the suspect spots. 

So, it feels good to have some positive news, but now what?  How can this be in light of the fact that I put a relatively new collector assembly from a 736 on there and it didn't correct it?  Wheel play moving the chassis?  I could run a wire from this engine's tender as a permanent solution, but not if this can be corrected otherwise.  Should I try and squeeze that rear drive wheels together to try and eliminate the play?  Or is there another way around this?

With everything you have done, this seems like a geometry issue that is causing the rollers to pull up and cause a loss of power. That free play in the rear wheels seems like a likely culprit (not sure how to correct that, leave that to other experts), but I suspect that is the cause, not the roller assembly/springs (the 736 would have corrected that). It is going to take observation of the engine going over the switch, and probably trial and error, to figure this out. 

I would remove just one of the jumpers and run it. If it still works, that narrows down whether its the wheels or the rollers that are causing the problem (depending on which jumper you chose to remove .) Quite easy to do!!!!

George,

To each his own, but to me, THIS is the real fun part of this hobby. Troubleshooting, fixing, modifying. Unraveling the cause of something like this is a journey. Can be frustrating, but you can't beat it when you figure it out. And it helps to have a great Forum like this.

And speaking of 91 breakers, I'm probably preaching to the choir on this one, but I've been using them for 6 years and they are terrific. What pushed me over the edge to try them was CW and Rob, proponents of their use. I've wired mine in series with a friend's PH-180 brick and the 91s trip first. Incredible.      Provided your amp load is under 6

George,

Ok, I removed the jumpers one at a time and here's what happened. First I ran it again with both jumpers on just to make sure it wasn't a fluke. I got no stalls. Then I removed the jumpers between the rollers.......stall.    Put that one back on and removed the frame jumper.....no stall. So....it appears it's a roller issue. But, seems to me it is either because the wheels are shifting with that play we discussed or......maybe the rollers themselves need to be replaced. They don't have a groove in them, but they can't be new. 

I'm tempted to squeeze those rear wheels. 

Setting up a permanent jumper in and of itself is not a problem.  I've done it with my 3 PW Alco sets........I added a motor to the dummy unit and tethered it to the e-unit in front. They pull like F3s now. But that was to get an improvement. If I can correct this without a tether, I'd prefer it, but, I know it would work if I can't fix this. 

Roger

First, clean all the wheels, track and pickup rollers with Naphtha. If the rollers, wheels or track are rusty, clean them with fine emery paper. If the entire roller pickup assembly is rusted, replace it. Once everything is new and clean, you should not have any stalling issue.

Thank you, I was beginning to think that Postwar never had any problems.  Little clean, little lube, little love, good for another 50 years.

Chris Sheldon

Chris,

Well, in this case, cleaning wasn't going to help. It wasn't the issue. It was/is a real puzzle. But the tether corrected it, but I think we're reaching consensus that wheel play in the rear drivers is causing a chassis shift. We'll see

C W Burfle posted:

E-unit ground leads are either soldered to the e-unit frame (rare) or spot welded in places where you cannot see them.

Don't think I've seen this. The wires from the e-unit coil are soldered to the terminals on the fiber plate.
What parts of an E-unit are soldered or welded? The only exception might be the e-units that don't have a lever.

Ooops! Brain fart! You are of course, correct. One end of the coil goes to the hot terminal, the other to the ground switch. I've been working on the 3356 horse car below, and that coil is what my brain was still seeing!

ROGER1 posted:

Chris,

Well, in this case, cleaning wasn't going to help. It wasn't the issue. It was/is a real puzzle. But the tether corrected it, but I think we're reaching consensus that wheel play in the rear drivers is causing a chassis shift. We'll see

"Wheel play in the rear...." - you are referring to the rear drivers I presume? So to clarify, the thought is that the back end of the engine is allowed to swing right or left due to drivers that are gauged too narrow, correct? Could this possibly result in the contact roller sliding off to one side of the center rail, juuuuuuust barely losing contact for one of two nano-jiffies?

George,

Yes, the rear drivers appear to have a bit too much play. CW said that "too much" occurs when it rubs on frame or other wheels.  So, I went back and looked closer. The rear pair has 1/16 inch of lateral movement. Enough movement to cause one of the rear wheels to contact the wheel in front of it. Observing it with my magnifier shows a groove being worn in it near the flange base. 

I did your jumper test and it appears like the rollers are the issue as then the jumper from tender rollers to e-unit is in place......no stall. So.....somehow the engine rollers are losing contact momentarily. CW seems to think that the rear wheels moving laterally, could cause the chassis to move laterally.  In  light of the fact that swapping the collector assembly out for a 736 one doesn't correct the issue on this engine.....I guess it's possible. So, now I have to decide if I'm going to try and squeeze those rear wheels a bit closer together. 

Or just use a tether.       But that wouldn't correct the wheel contact

So cool to read the thread from top to bottom from the statement of the problem all the way through some great analysis and recommendations to an eventual solution, we hope.  The Postwar stuff is pretty easy to work on when stuff goes wrong, especially with the help of this forum.

Chris Sheldon 

Is the problem with the rear drivers that the axle bearings are worn which is causing the drivers to make contact with the ones in front?

I could be wrong, but I don't think they are worn, I think they are gauged a bit off.There is no fore and aft movement. It's all lateral

If there is too much lateral movement then could it be that the hubs on the back of the wheels are worn down to give this excessive movement?

Moving the wheels in will remove the lateral movement but then will take the wheels out of gauge.

Answer could be to change wheels to a good pair either new or used or alternatively take them off and add some shim washers.

So to clarify, the thought is that the back end of the engine is allowed to swing right or left due to drivers that are gauged too narrow, correct?

I don't think so. As has already been said, the worm gear arrangement produces side pressure, causing the back of the wheel to rub hard against the face of the bearing, causing wear.

If there is too much lateral movement then could it be that the hubs on the back of the wheels are worn down to give this excessive movement?

I think it's the bearing that wears.
Regardless, replacing or resetting the bearing will address the problem, as would adding spacers between the wheel and bearing.

On Berkshires and turbines the flanges of the end wheels extend behind the next blind wheel, so it is possible for the bearing to wear to the point that the flange can rub on the next wheel.

Another type of wear is when the axle holes wear, making the axles sloppy in the bearing.

I have seem locomotives with both types of wear, and locomotives that had reasonably tight bores (axle holes), but worn ends.

If it's just a worn end, I usually will install 671M-23 or 671M-19 washers. The trick is to guess whether to use one or two. It is a whole lot easier than replacing bearings, especially since many of the bearings available today require reaming after installation.

I have the tools to remove and replace wheels.
For those who do not, some people report success using horse shoe washers, or bread tie plastic to make a ring with a slot that will snap over the axle.
I forget the exact application. Somewhere in the Lionel manual they recommended cutting a slot in a washer to snap over a shaft or axle.

Something similar can be done to fix a loose e-unit lever. I think some folks put the washer behind the spring washer. I have put the washer between the fiber plate and the metal e-unit frame when I don't feel like taking apart the top of the e-unit to get to the back of the eyelet.

CW,

So, it looks like we're back to square one. If the lateral movement is not causing the stalling from the e-unit, then what could possibly be going on under there?  The jumper test seems to indicate that the rollers are the issue.   It's looking like a tether would have to be the solution.  But I'd have to get those wheels repaired as that's not something I could do. But I'll see if I can find the description of the washer mod in the manual.

Roger

Not very likely the cause but were the roller pins cleaned and polished when the pickup rollers were replaced?

Not very likely the cause but were the roller pins cleaned and polished when the pickup rollers were replaced? 

The rollers were nubbed. They are completely cleaned. And.....I swapped out the whole assembly for one on one of my 736s and it made no difference.

So, it looks like we're back to square one. If the lateral movement is not causing the stalling from the e-unit, then what could possibly be going on under there?

How do you know the lateral movement isn't causing the e-unit to cycle (by causing a circuit interruption)?

I assumed you tried a single jumper, just for the center rail, to isolate the problem to the pick-up?

Did you check your 671-200 collector terminal?
the part that contacts the collector should have a little curve to it, which provides pressure for firm contact against the collector. Often they get flattened over time.
Maybe you have a contact problem.

The picture of the part is fairly accurate in the service manual.

CW,

Yes, I mentioned above, the test I did. Two jumpers and then removed them one at a time. With the tender roller to engine roller jumper in place....no stall. Taking it out.....stall. 

Did you check your 671-200 collector terminal?
the part that contacts the collector should have a little curve to it, which provides pressure for firm contact against the collector. Often they get flattened over time.

Yes, I have that opened up about 5 times. It had a curve to start with. I bent it a bit more. I also sanded the brass contact and underside of the roller assembly

I like CW's discussion about taking end play out of the axle/driver combo. I have done similar on a 2024 diesel with tons of slop, and it was a good solution. As I recall, I added shims (washers) to just one side to effectively move the worm gear to one side, exposing fresh metal where it mates with the worm.

If you have a horseshoe clip (or two) handy, it would only take a couple of minutes to test this theory. Stick a clip on one end of the driver axle and run the train. If no difference, put it on the other end of the axle. If you have room, put clips on both ends. If it fixes the problem, then you can either leave them in place or pursue a more elegant solution with wheel removal, new parts, washers, etc.

Hook up the tender roller to the engine and use a small connector to separate them when needed. Unless I am misunderstanding (and I certainly could be ), the slop in the drivers should not cause a loss of power. If the tender pickup resolves the issue, schedule driver maintenance at your conveniance and enjoy running you engine.

George,

Im going to try the horseshoe clip  I have nothing to lose  if it doesn’t work, I’ll have the wheels repaired. I’ve got 1/16 inch of slop. Plenty of room for washers  That’s close to twice what some of my other steamers have

Mike,

I’d prefer to remedy the stall issue rather than use a tether. I’ll see what happens after the washers are in....whether it helps with the stalls. Lots of things happen under there as it rolls over those 1122s.  Something is losing contact somewhere.  I must be missing something

I would not put clips on both sides.
The wheel set is pushed to one side going forward, and the opposite side going backwards.
Unless that loco has been run backwards a whole lot, the wear is going to be on the side which has the wheel rubbing against the bearing going foward.

By the way, it's my impression we have been discussing a 1947-49 Berk, making it approximately 70 years old. It's going to have a little wear here and there.

C.W.,

Would you happen to know the diameter of those axles?  I think I have clips and some thrust washers but I might want to Drexel a slot into a slightly thicker washer to take up more of that 1/16 inch slop on the one side

Have you tried running the engine with jumpers with the drive wheels off the track and  suspended, if it runs put pressure on the side of the drive wheel(s) to see what happens.

Nairb,

I’m not following that.   ???  What is the intent of that?

CW,

I just now read an old thread in Classic Toy Trains Forum. Bunch of guys with 726s that had play in rear wheel pair. They used the method I considered.....cutting a slot in a washer. The thickness of it was ..04.    Two questions.....they put it in the gear well.....between the worm and frame. Do you recommend that or putting it between the wheel and the frame?  I'm thinking it's easier to put the washer on the axle in the well (or remove it if it doesn't work out).  I also need the diameter of the axle so as to pick the right size washer I.D. 

Roger, while it should have nothing to do with your stalling problem you might want to check to ensure both rear drivers are tight on their axles.

I've serviced many Berks and Turbines that were poor runners because one rear driver became loose on the axle.  The wheel won't fall off because the flange rubs on the 3rd blind driver.  In one direction the rear driver rubs on the frame, and in the other it rubs on the driver. 

Worth a check, John. Thanks!  Pretty sure it's real tight, though.

Engineering manual says the axle diameter is .1875
Put the spacers in the well for the worm gear? .
I don't know. I wonder whether the spacers might catch on the splines for the worm gear.
You could try it and remove them if they bind.
It would likely be much easier to get the washers snapped over the axle by the worm gear, as opposed to behind the wheels.

I remove the wheels and either use solid washers (671M-19 or 671M-23) as spacers, or reset / replace the bearings.

I just now read an old thread in Classic Toy Trains Forum. Bunch of guys with 726s that had play in rear wheel pair.

I'd be interested in reading the thread. How about a link?

CW,

Thanks for that info up above.  I've got a .04 washer that I'll cut a slot in a bit smaller than the axle.  And yes.....I think it will be easier to get the washer on in the "well". And more importantly.....get it off it it goes South.  That thickness washer should get rid of all of the extra slop in that wheel set. 

Here's the link to the article.....interesting

http://cs.trains.com/ctt/f/95/t/88765.aspx

Roger

CW,

By the way, it's my impression we have been discussing a 1947-49 Berk, making it approximately 70 years old. It's going to have a little wear here and there.

More prophetic words have never been written. Incredible night.  I opened up the gear well and then got out my Dremel and cut a groove into it and shoved it onto the axle next to the worm. Flipped it over to check wheel bite. Perfect (or so I thought). Ran it on the layout (still without the shell). It ran well, but I had no jumpers on it so it stalled (a bit disappointed with that, but....I figured, I fixed the wheels).     NOPE  

I checked the wheels again and it appeared to be hitting again on the bad side. How can that be. I happened to be rotating the wheels and thought I saw a wobble. Connected to alligators.....yep, a wobble (but it gets worse). I thought....bent axle...I don't have much to lose to try and bend it back a bit.     From John below

Roger, while it should have nothing to do with your stalling problem you might want to check to ensure both rear drivers are tight on their axles.

I set up some blocks to try and bend it and lo and behold, before I did that, I grabbed the wheel and twisted.......LOOSE. And......it won't tighten. I have to admit defeat on this one. Got to send it out. Can't do wheels.  So......that rear pair caused a boatload of things. 

70 years old!!  Kind of like alot of US.

Roger

So that's it (most likely), the root cause of all this evil was a loose wheel?

I still will be curious to see if a repaired wheel fixes things - been a long road so far, kind of like some of my projects 

Well, I hope you get it sent out, repaired and are happy. Also hope the new wheel color matches the old....

A squared off feeler gauge (automotive...common) with a U sliced in it its end with a dremel will remove hidden C-clips. 

I ve had three posts on this page fail & the composer freaks out .  Just this page.

I think the roller is long enough to bridge the gap. and unlikely to wander off the center or it would do it in regular straights too. (look below) The issue with O on 0-27 is usually the roller falling off in turns (or chassis hitting the coil cover on turnouts or lack of articulation for the turn, or flange bind on huge steam ... but we are talking rollers)

Roller check: tape one roller off. if the loco is dead, or stutters, etc., the untaped roller is bad. 

Can you tweak the roller arm pivot tabs to one side? (check it for lateral play too.)

TESTS...

Tape the red areas; being careful to stay off the top of the center rail for the carefully cut short piece. 

  If it makes it (or hangs up on it) you are likely shorting the backs of your wheels. (I know things point to center but check as AC shorts do funny things)

LONG TAPE: cover over this, it is not in use other than being there to short againt.  I'm thinking it the point rails rivet is loose, wieght may rock the points lifting the other side (right side) enough to short on the wide roller. Carefully measuring the rivet location you can drill a big hole in the thin bottom for access to set it better. there is a trace there under it, but the rivet should protect it at breaktrhru.

  Squeeze your center rail connections again, maybe pull the pin and clean & maybe oil it if rusty. These connections are always cry babies. (if you have a fiber pin on center, extending things like that & anti derail 1 track might help.

Lionel has always suggested a lock on (3 total) be used as close as possible to the 3 legs of each turnout .  This takes a load off of power NEEDING to pass thru the turnouts rivets etc.... long story short, wire makesfor consistency in power feeds

And when you do things like pins, tests, etc. do them one at a time, and note results so in 5 years you might recall where to begin again

Covering the point rail alone, not bothering with the short tape, if it shorts, your gauge is too narrow. The long rail should keep that short from ever happening at proper width.  Just look.

Adriatic,

Glad you stuck with us through all this. I'll have to do those tests when I get it back (hopefully with new wheels and bushings on the rear). Thanks for that. 

It's funny, though......I've got tape on many of my switches in the exact places you've got in the photos. One thing about 91 breakers.......they cut you no slack. The slightest short and they instantly cut out. So, I start out using tape to find the places where the rollers slide down to a side rail (especially on a swivel) or a pilot wheel tapping the frog. Then.....it gets either a small piece of tape or.......super glue......and my work is done. But every new engine I get.....it has to make it across the mine fields. Most do, but every once in a while, I have to tweak it. But this one came out of nowhere. I've had it for 5 years and it ran flawlessly.  But as CW said......it's 70. 

Also.....about the rocking swivel. I get that occasionally and the tape usually solves it. This time, I put a shim under the swivel to keep it from rocking up. Still got stalls. So.....I replaced that switch. Smoother ride. With these 1122s.....if I get rough, noisy rides out of them (or too many shorts), I replace them. They are all wired through the bottom for fixed voltage with a capacitor system to help power it. Works great. 

Roger

Roger1... did you figure out the problem on your 726 ?

I have a similar problem with my 736 when it goes over a couple of my turnout switches (6-23010, 6-23011).

I suspect my e-unit as I did attempt at servicing it last year, and just recently put everything back together, which wasn't easy, but it seemed to be working as far as switching to forward and reverse.

I have another 736 that I tried running on this same section of track, and do not have issues with it.

Airmojo,

Yes, the 726 is fixed. Lots of stuff was wrong with it. Mainly wheel issues. I don't have the tools for those repairs so I sent it out to Chuck Sartor on this Forum. Good man and excellent repair person. First off, it had a warped drive wheel. Also had worn out axle bearings (both issues were on the drive pair). The axle gear was also replaced.  But it kind of escalated from there. USPS must have used it as a football. The box was dropped in shipping (both ways). Broke off the rear truck and flattened the tow bar. Bashed the front pilot and bent it. When dropped again, it broke off. Had to find a new pilot, paint it to match and replace it. Chuck fixed the rear truck. The movement of the worn drive pair was causing the shorts going over some swilches......some roller and some wheel to frog shorts. 

Sometimes the fix is easy.  This one was not

Roger

Thanks for the update Roger... that was quite a journey... I hope mine isn't anywhere near that troublesome !

I may have to look Chuck Sartor up sometime... where is he located ?

I have my limitations in know-how and patience, although I do like figuring things out and fixing them on my own when possible !

Airmojo,

Chuck is located in Colorado.

Is that engine tripping a breaker or.......stalling (actually, shifting into neutral). If it's the second case, most of the time it's a relatively benign thing. Steamers rattling around over a switch produces lots of movement underneath. A wheel (often in the pilot truck or trailing truck) taps the frog. Stops it.  Or a roller tapping one of the ground rails. Look for sparks or.......pitting on a rail.  Judiciously placed pieces of electrical tape solves those. You can experiment with the tape and when you find the spot(s) take the tape off and paint on some Super Glue (works the same).   Some engines just don't like switches.

Roger

It shifts into neutral, and then I have to hit the direction button on my KW, and it goes in the opposite direction, but will shift into neutral in either direction after passing over a turnout switch, but not all the time... it runs fine when I lock it into the forward direction.

I'll have to try the tape on the turnout switches... I remember seeing a photo someone posted on your thread.

I mainly ran this 736 on another track that is just an oval with passenger cars and a Railsounds tender... had what I thought was issues with the e-unit when I tried to set it to only go in the forward direction... I fooled around with the e-unit, taking it apart and cleaning, etc... turns out I wasn't "setting" it properly to keep it going in the desired direction until I read this page in an old "How to Operate Lionel Trains and Accessories" 64 page little book that I picked up at a train show...  I guess I always assumed that the e-unit could be set to accomplish this, but apparently not because this procedure works great... duh !

Here is a scan of the page... I picked up another 736 locomotive at a local antique show at a good price, and it works great... I decided to put things back together on the original 736 and tested it on my outer track that has turnout switches, mainly for parking trains, so I can run other trains on it.

If it happens on particular switches, you have to locate the offending spots. Time consuming. You have to watch the engine as it passes over the switch. You'll see the wheels (usually in the trucks) rattling back and forth. Look for sparks. Then start with large pieces of tape. If it stops stalling, reduce the size of the tape strip until you've covered the spot with a small piece.    You can even push/pull the engine over the switch. If it's only happening over switches, this may be your issue. I hope so......cheap fix. 

Another thing to consider (also easy fix) is a loose e-unit attachment screw or......a loose lever. If the lever is loose, I jam a thin piece of styrene behind it to tighten it (creates much better contact). 

Ah, works.

  If wheels weren't the sole issue... (I could easily see some craziness with the height, tracking, angle changes; level of roller etc.. my wobblers actually run pretty well without any issues {other than one overheated E-unit finger that curls upward easy and cools that way somedays. Wait 5 min to a week  and its fine again} .

..... and had you not only pulled the swivel up raising the whole point rails to prevent rocking, but pushed to too, it might have gone differently. Had you pushed it down also it might have cleared up somewhat on that alone. 

  I didn't re-scan this whole thread or recall my own words verbatim and the important thing is you are running again and though no fun then, you have a good beer&BS story to rant with now, eh!... but my thought in it tilting almost certainly was concerned with them being too high or too low, but too high would be where I'd expect shorts more often.  

  Sounds like a hi-lo got smashed it with two wheels while turning around maybe?

😠 Always sucks... but ...

   Ever see Nashvilles airport when the countries shipping transfers all arrive "at once", get unloaded, "switching" moves are done, reloading, and the planes are airborne again asap? All over and done with in lighting speed and hopefully precision. It's like watching bees, schools of fish crossing paths, or Asian "Zen driving" where signals don't exist and its all about merging skills.

Like walking busy halls of a high school where everybody is racing a bell with huge stack of books and papers due they don't want to drop.

... oh man, I dropped a single sheet..what to do?

  You gotta keep going if you only lost 1 of many. Stopping etc. in the wrong place could easily upset things far beyond most items values.    

I'd never ship a shell today if I could avoid it.  Just the motor/frame alone.

  No insurance on it?   

The engine was sent back and forth 2 times. The second time, I stripped it down to the frame. I did have priority mail insurance on it, but didn’t file a claim. Wasn’t sure how much of a hassle that would prove to be, so I ate it.  But the costs we’re getting close to what I paid for it.  Wheel issues can be expensive

   Presswork takes tools, time, & parts that like anything else add up.

  But the payoff is the lifespan you may not have (but should have ) considered before your initial buy has now expired; the stopwatch reset. 

 Actually I think I have enough enough confidence in most of the folks around here to be able to do all but some "trick" jobs. Chuck makes the grade easy; smart, open, broadly experienced. 

  I seldom concede to the "I can't theory". There is only haven't; couldn't; shouldn't. The two former are opportunities, the later?; Well..ok. I won't go near the Ocean again without a vest and yet I have swam miles at a time across lakes. ..Same kinda thing 

  I need a full 2037 rebuild, for sure the magnetraction bushings & gearing done, maybe a post too. Im beginning to wonder.... though not for sale (no supply left ANYWHERE 'i' can find), I haven't asked around for techs  that may have some saving them for repair work.  "I'd pay him the nominal service charge" for the work. But I kind of want to do the work myself, bonus for them. This one is special; not running; but here every day of my life. 

 Nice used?🤔😣😕😒..o.k. how much?

  My intent wasn't a hi-jack though it kinda ends there. But a point as to how I feel confident about the things a hobbiest can possibly do for themselves. 

  IMO folks too often panic slightly or rush while assessing something a few times and develop a lack of confidence of sorts, or had never been allowed to explore their mechanical abilities due to that same lack of confidence within "folks in charge" during the oppotune moments for that person, and the next thing you know... "I can't"....

...I say haven't... yet! 

  75% of my young assistants had this problem when they would start.

  Ive had 4 contact me later in life like I was an fav. old teacher... I guess I was, but "slow down".