Thomas Tank Engine Mechanical Issue

Yep Chuck, I tried with all I could muster, couldn't get any movement.  It is an interesting thought though, maybe I'll try again.  I didn't want to screw it up by bending the axle, they're almost impossible to perfectly straighten again.

Hey John,

I was just re-reading all of your previous post. I had missed the part where you

had removed the side rod connections with the front axle. And the engine ran fine.

Sorry for leading you down the "side play" and "wheel shiner"  path. I think

Tom and Chuck are on to it. There seems to be someting wrong with the front

axle assembly.

Joe

Yep, I just can't figure out what it is.  I measured the angle between the left and right wheel rod connections, it's exactly 90 degrees for the front and rear wheels from side to side.  The middle wheelset is slightly off, but even if I leave those screws out, I still have the issue.  Those wheels are pretty much for show, and they have a big sloppy slot to allow them to flop around.  They also are just held down by a little weak spring to make them look like they're doing something.

It's a mystery!   The one thing that strikes me is the traction tire picks up the opposite wheel and drives the inner wheel into the curve on left hand curves, that's the one that's got less distance to travel, and it's the only time the issue surfaces.  That seems to be a clue, but I don't know the cure.

How did you install those cool lights on the thomas?

John,

  You can safely pull out a wheel set and swap it end-for-end without disturbing the quartering. No need to pull wheels off axles and press them back on. Pull out the wheel set with the traction tire and reverse it in the frame and try the loco again.

Larry

John,

I know it sounds stupid but did you check for GOOD continuity on the ground side through the wheels and and the pick-up rollers and cables?

I've had a very similar issue and it turned out that the red wire from the pick-up had

a poor connection but only under load. when the engine was on "its back" and I applied power it ran just fine but by creating a little drag on the wheels it started to

cut out - just another idea.

Achim.

 I had an engine with a similar problem. I found it by running it very slowly freewheeling (no load). The engine would stall when the wheel would get to a certain clock position and struggle only there. You could feel it when spinning the flywheel. I think I had to take the slop out of the siderod? The ungeared wheel set fell behind.

http://www.rayman4449.dynip.co...vers_Binding_Fix.htm

My Thomas engine would stall on certain 022 switches. Turned out only one axel was grounded. There were times when I was sure the side rods were conducting the ground. I removed the bottom plate and cleaned the white grease off the contact where it was riding on the axel. That solved my stalll problem. If grounding is not the problem I would think about enlarging a side rod screw hole by one minute drill size and see what happens.

How did you "take the slop out" of the rod?

They're driven off the TMCC board I installed, it's an ERR Mini-Commander 2 with a Sound Commander for sound.

I'll give that a try, if they're symmetrical, I'll try reversing the front set too.

I adjusted all the contacts, and all three wheelsets have good continuity to the common.

John,

I just watched the video 2 of 95 as it was labled.  A couple of the other guys are thinking like I am.  I just happened to have the sound turned up pretty loud with my headset on and when it hits that curve it sounds like a voltage hum is occuring.  Kinda of like a short.  The split second it gets off of that piece of curved track, the hum stops and it takes off.  The only thing that doesn't make sense in this case is the fact that what you said about taking off the front rods, you said there's no problem.  Are they conducting electricity in any shape matter or form such that a short is occuring somehow.  Doesn't seem possible with my limited knowledge so far.  Have you tried with one rod on and the other off?  And vice versa.  But that hum sure seems to be timed exactly when the problem occurs. 

The hum is the motor laboring since it's stalled, I can force the same thing simply by holding the locomotive and turning up the throttle.  There is good grounds on all the wheelsets, I adjusted the axle contacts and checked them with a meter to make sure all were making good contact.

90% success!  I swapped the driver wheels around and connected everything up again.  Now the traction tire is on the other side.

I still get a slight hesitation at very low speed making left turns, but at any speed it's unnoticeable.  I'm thinking this is as good as it's going to get.

Thanks everyone for your input, learned a few things with this experience.  TrainLarry gets the gold star for his suggestion of swapping the driver wheels.

Thanks, John, for my first gold star!

  Lets have some fun, now. Run the loco in the opposite direction and see if the problem occurs again. Curious to know.

Larry

I'm almost afraid to say it, but I was thinking the same thing too.... : )

The engine still runs fine making right turns.  I'm thinking that to finish the task, I'll look at shimming the front axle a bit forward to see if that removes the last hesitation.  I still see it if I have a few cars behind Thomas, so the 90% is about right.  Clearly, it's some issue with the rod quartering, there are just limited options to fix it.  It's also clear that there is a difference between the left and right wheels, since moving the rear drive wheels changed things.  Of course, the traction tire is on the other side now, which changes the dynamic also.

John,

  Check the play in the rods at each wheel, on both sides of the loco, as it is sitting still on a straight stretch of track. Now run the loco to the point where it gives you the problem and stop the loco. Now recheck the play in the rods at each wheel, on both sides of the loco, and compare with your first test. This should tell you exactly where the problem is.

Larry

I tried enlarging the holes in the rods slightly, that was a mistake.  It's worse again!

Right now I have the front screw out so it'll run properly.  When I put a few cars on it, the problem showed up more, when it was running with no load, it ran fine.

What a PITA, I wonder how many of these actually run properly?

John,

  You mentioned that there is some fore and aft play in the front axle. That may be the cause of your problem. As the loco enters a curve, the distance between the front drivers changes with relation to the others, which would cause the rods to bind. If you have some thin wall tubing, you can cut a short length, cut it lengthwise and snap it around the axle where it rides in the frame. If no tubing, perhaps a narrow strip of kitchen aluminum foil wrapped around the axle will suffice to test the theory.

Larry

I'm not sure there's enough space for me to shim it.  I probably have to get some new rods now that I've enlarged the holes in these, since it made the problem worse rather than better.

John,

Lionel sent me a new set of rods under warranty but it didn't help...mine seems to labor to the point of just not moving on the straights too, so I'm resigned to running with no side rods.

Ed

I currently have the front wheels disconnected from the rods, runs fine that way.  It still has the rods and they look like they're doing something.  Since the front wheels don't really contribute much to the traction, that may be as good as it gets.

I thought I was done until I put a few cars behind it, then it had the same problem in right turns.

I'm still going to see about shimming the axle, but I'm beginning to lose hope at this point.