Walthers FB-1 running poorly but only in one direction

Hi -

I've got a Walthers FB-1 loco that has taken up running poorly in reverse. Smooth as glass - even at crawling speeds in forward - but in reverse, it moves in spurts. "Fast" and then slow. I tried cleaning the wheels and the contact points where the metal springs graze the back side of the wheels (whatever those are called) and carry current up to the motor, but that doesn't seem to have made a difference. Anyone have any suggestions?

thanks-
Joe

I should probably mention it's DC only.

Is this a Proto or Trainline loco?
Check if the axle gears are cracked,if it's a Proto(Athearn clone) try to find replacement Athearn axle gears.
There's been a problem due to how the axles were put on in China,and tend to crack over time.
If it's a Trainline,if you still have the parts list,try getting replacements from Walters.

use volt meter to test motor leads in both directions,you may have bad can motor

It's a Walthers Trainline.
I was not aware that Proto was/is an Athearn clone. Interesting.

What's the secret to taking the shell off this FB-1? I'd like to do this without damaging anything and the process is not obvious from just looking at it.

OK... I figured out the shell. A volt meter shows that the motor is producing the same (& steady) voltage in both directions; not sure if that was what I should be looking for.

I shot a little video of a "test run" of this loco on my coffee table: http://youtu.be/al4oLqwbQ-U" onclick="window.open(this.href);return false;.

Any opinions on this? There is a visible waggle in the front truck only when running in one direction vs. the other. But, if you listen to the motor noise in the background, you can hear the "surging" going on. And then it runs nice and smooth in the other direction. A friend had suggested this might be a gear problem, but is it possibly electrical or motor-related?

looks like a bent wheel?only way to find out is to take apart the truck and inspect for cracked gears(doesnt seem to be)I don't recall if
they have 2 piece axles or not but only 1 way to find out.

The drive is possibly a Kato/Stewart clone,1st unplug the pickup wires from the light board,2nd remove the clip that
holds the truck to the underframe,have a cup or small container to keep small parts in,the drive shaft from the motor will be now loose.
3rd,remove the sideframes,be careful the electric pickupstrip/bearing will be loose,4th,at this point a couple of small clips hold the gear tower together,
remove and inspect the axle gears,the wheelsets are stub shafts that are pressed into the axle gear, if they are not straight ,
you might be able to get a replacement from Stewart or Kato.
Check all the other gears for broken teeth/misalinment or damage.

Hopefully you still have the exploded view parts list to use as a guide!!

I have a 4 axle walthers trainline that I can take apart and take some pictures if you want,I have 100's of spare parts to see what can work,
I was gonna say you can pick 1 of these up from a train show for around 30-40 dollars but you may run into same problem,but I'm off a project
so I can take apart this trainline engine today to see what it looks like as I will be upgrading it

[attachment=2]SDC13051_1094x820.jpg[/attachment]Here are the pics

Pics

Pics,last pic the truck has solid axle,look for cracks,take wheel sets out roll on track to inspect(easier if you have NMRA wheel,track gauge)

Wow, thanks guys. I'll check this out. I won't get to it tonight but hopefully in the next couple of days I can get a chance to look at it.

Alright, I took a shortcut. That turned into probably a long cut.

Here's what happened. I have another identical Walthers FB-1, so a friend suggested swapping the trucks out to isolate the problem. If I put the trucks from the good FB-1 into the bad FB-1 and it works well, then the problem is in the original trucks. Seemed like a good way to narrow things down, so I did that.

If you look at the PC300006.jpg file, there are two FB-1s in the picture. The Undecorated FB on the left is the original "Bad" one. It was the one running poorly in reverse. The Erie FB on the right was running fine in both directions. So, my plan was, take the front truck out of the Erie and put it in the Undecorated, then test it. The original front truck on the Erie was the one that had the waggle to it, so I figured I'd go one by one, and if just replacing the front truck fixed it, then everything's good and problem solved, right?

Here's where things get confusing.

I took the front truck out of the Erie. And despite the fact that it ran just fine, I noticed that the little plastic yoke at the end of the worm gear was cracked. So... new plan. After that, I took the REAR truck out of the Erie FB and placed that in the FRONT of the Undecorated FB. And since I was now down to just that one working truck, I put the undecorated FB all the way back together, and tested it.

The good news is, the undecorated FB-1 now works just fine. So, obviously the original problem - the "surging" and waggle - was coming from the original front truck.

The bad news is that the Erie is now down to two shot trucks. I'm sure the cracked plastic yoke (see attached "cracked.jpg" photo) is no big deal to fix/replace. But going back to my original concern, I don't see any cracks or other problems with the gears in the original front truck (or either truck, for that matter.)

So, as a possible solution to the original problem, my friend has suggested that the problem may be the fact that there is slack in the worm gear, which allows the gear to move back and forth when you switch directions. See the attached "gear-slack.jpg" image - I put to arrows to show the space my friend says I need to shim out to solve the problem. What is the consensus opinion on whether or not that might be the problem?