James,

You may want to post this on the DCC forum for more results.

Arthur

My railtruck has displayed the same behaviour... began just fine and now jerky, precisely as you describe it. I'll follow the answers with interest!

I still think the DCC isn't the issue. When I run it on DC it shows the same behavior making me think it is purely mechanical. I have also reset the decoder to factory settings so the DCC is most likely not the issue. I'll post more after I crack open the the shell and look at the mech.

Well, I lifted the shell and found nothing wrong. Not much to see there though. I pried off the bottom of the trucks and checked that gearing, lots of grease but nothing blocking the gears. Put everything back together and ran her again, still binding. I tried to pry off the bottom of the trucks again and instead the entire truck came loose. Now I could see all the gearing in the truck and found where things were binding. I ran the truck along my hand until there was no more binding and remounted the truck into the loco. Nice and smooth again. Next I changed the DCC loco number during which the loco will jump back and forth a little. After this the binding was back. I popped out the trucks again and cleared the binding and things seem to be great now.

It appears that during the jumping the gears get slightly out of line. By taking the truck out and running it along my hand without the motor gearing preventing the wheels from moving, just a little bit of rolling will return the gears to their proper non binding alignment.

I will have to run things for a few days to see if this is a temp fix or more long lasting.

James

My 45 tonner runs smoothe and slowe.....

The only jerk I have is the one operating the throttle!

Even the tiniest bit of stuff will bind the gears....and

it floats around with the grease. I think it would be a good idea

to strip down the motors and clean all the grease out and

put a small dab of clean stuff back in. My guess, it will cure the problem.

JMO.......Geezer

Zekjet, I had a similar problem...one of my mechanisms for the Twin Schozzers I am building started running noisy in reverse, no binding, but it was really noticable. I stripped the mech down to the drivetrain looking for a cause, and could only marginally improve the performance. It seems with our little Bachmann trains, some run 'sweeter' than others!

It is most likely that if you have a bind at the same location each revolution, one of your trucks is binding. Remove the cab, and loosen the two screws that hold the two sides of the mechanism together. That makes it easier to remove the trucks. Then gently pry the trucks loose from the frame. I use a large pair of tweezers inserted between the truck and the frame, and then gently pry the truck free. Be careful to hold the trucks at the front and rear, NOT by the siderods, or you will bend them.

Once you have the trucks off, roll each on the track to discover which one has a bind. You can then examine the gears in the truck. Most likely, there is a bit of gunk or small piece of delrin that is stuck in one of the gear teeth, but it's impossible to tell. If you narrow it down to the problem truck, you are on your way to a solution.

To re-insert the trucks, gently push the truck back into the frame, it should snap into place. If it doesn't fit right, don't force it, just pry it loose and try again to get a good fit. The trucks should be mounted with the little window showing the gears facing AWAY from the cab on each truck. Refer to the Bachmann diagram if that doesn't make sense. Tighten the screws you loosened on the frame, and test. Good luck if you try this, I have found a little fiddling can work wonders sometimes...

Could this be caused by a split gear? Several of my friends had similar issue on their Bachmann railtrucks.

I'm still getting the slight binding on one truck. Now I believe there may be a bit of flash on the gears and that is causing the problem. I've had a split gear before on an MDC Shay, this is not a split gear although it kind of acts like one. I'm going to try scraping down the tips of the binding gear to see if that is the issue.

James

Many of the Bachos have a delrin or nylon gear friction fitted to the axle. The co-efficient of expansion of each of these materials is different.

Thus the gear often cracks because the axle has expanded. Carefully check the gear on each wheel set with a glass or optivisor. If it is cracked it needs to be replaced. I have gotten such parts from Bachmann, good luck.