Bachmann 2-8-0 Drive System

[trainat114]

I recently purchased an older Bachmann 2-8-0 HO DCC with sound. It looks great and the sound is quite good. However, there is a problem with the drive mechanism. The motor turns but the engine does not move. I can get it to go with a Little push but it stops each time it gets to a hill. The motor keeps turning but the engine does not move. I disassembled it and checked it out. The wheels roll easily when disconnected from the drive system so the problem is not in their alignment. When there is any resistance at all on the system the gear on the motor drive shaft, the one that turns the little belt, just freewheels therefore the motor turns fast but nothing else happens. Looks to me like the system was designed to fail! Any ideas? They sell new motor kits but I wonder if that would help, it might be just as bad as the old one. Any suggestions? Thanks Ed

[jonathan]

Ed,

If you disassemble the frame halves that hold the motor and belt system:

Look for a split drive belt.  I've had two split belts from the factory.  The part is inexpensive and available.  Do a search in the HO parts section. It's an easy fix if you are use to tinkering a bit.

The belt does not typically wear out, but can be split during factory assembly.  I don't know why or how.  Both my issues displayed the same symptoms you describe.

The other problem MAY be the worm not seating properly.  That's a more rare issue.  Jim Banner, who frequents the forum, described an easy fix for this as well. It involves making a heftier bushing (or is it bearing?) for the worm axle, out of a small piece of brass tubing.

I'm guessing it's the belt.  Hope I'm right as that is the easiest fix.

Regards,

Jonathan

[trainat114]

The belt looks fine so problem must lie somewhere else. Thanks for ypu info. Ed

[bapguy]

It could be the gear/fly wheel part on the motor shaft is loose. If you can dissasmble the loco,  take out the motor, hook up power leads to it apply power and see if the motor will still spin when the fly wheel is held. If it does, this is the problem.  Joe

[trainat114]

The fly wheel is tight. When I hold it the motor stops.  Thanks Ed

[jonathan]

Ed,

We seem to be running out of options, or a diagnosis anyway.

When the frame halves are together, do the worm and belt look like this?



Here are a couple of shots with the belt on and belt off.  Look at the worm shaft and bushings closely.  Does yours look like this?





If the motor, pulley gear, and flywheel are all secure and running fine, AND the wheels are turning freely, it seems logical the problem lies somewhere around the worm and it's connection between the motor and the gear on the drive wheel axle.

So, what lies in this area?  The belt, but that is fine.
                                      The worm mechanism, including shaft and bushings.
                                      The axle gear itself.

The frame might have a bad casting, not holding the worm shaft properly.
The axle gear could be split and slipping on the axle.  This would be a first for the Connie.

Just brainstorming with you, Ed.  Hoping we get a hit.

Regards,

Jonathan

[trainat114]

Jonahan,

Mine looks exactly like the pictures you posted. On mine the pulley gear, the one between the motor and the fly wheel, is not pressed onto the shaft tightly. In other words you can slide it back and forth a little bit and you can rotate it on the shaft. At first I thought this might be the problem but on second thought if this were not able to slip, it seems the belt would break if the drive mechanism ever hung up. Maybe you can shed some light on this. Does the gear on yours move or is it rigid?

You also mentioned the possibility of a bad casting that does not hold the worm shaft properly. You may have something there, the shaft does have some play in it. The end away from the belt end will move in and out a little if I push on it. Maybe I need a thicker bushing to take up the space.

Thanks for your interest and your help.

Ed

[jonathan]

That gear should be tight on the shaft. Perhaps it's split. This must be where you are losing your power.  Sounds like a new motor is  the answer.  I don't know what comes in the kit, vice getting just the motor.  Also don't know what your warranty options are.  However, sometimes is more economical to send the loco in and let the Bachmann folks fix it for you.  I think you did a pretty good job of isolating the problem.  A call to the service department couldn't hurt.

Regards,

Jonathan

[trainat114]

Thanks Jonathan, you have been a big help. I appreciate your time and effort. From the picture in the parts section it looks like the motor "kit" comes with the motor, fly wheel and gear assembled and the worm gear. That might just solve the problem. I agree that a call to the service department might be worthwhile.
Thanks again,

Ed

[Jim Banner]

When there is any resistance at all on the system the gear on the motor drive shaft ... just freewheels ... the motor turns fast but nothing else happens.
Thanks Ed

Looks to me like you nailed it right in your first posting.  Before ordering a repair kit, you might try a drop of Crazy Glue to see if it will hold the sprocket ("gear") in place.  Put the drop of glue between the sprocket and the flywheel so there is no possibility of getting any in the bushing at the end of the motor.  Let the glue set over night before you reinstall the belt.

I did not understand the nonsense about the system being designed to fail.  If a single failure in a single unit indicated that a product was designed to fail, then every product ever created by mankind was designed to fail.  Two of the most highly engineered products every made - space craft and nuclear power stations - have had failures but you will never convince me that someone stayed up nights making sure that parts he was designing would fail.

Jim

[Doneldon]

Before ordering a repair kit, you might try a drop of Crazy Glue to see if it will hold the sprocket ("gear") in place.  Put the drop of glue between the sprocket and the flywheel so there is no possibility of getting any in the bushing at the end of the motor.  Let the glue set over night before you reinstall the belt.

trainat-

Jim's idea is a great one. I'll add just one detail: Perfectly clean your gear and drive shaft. Use alcohol to remove all traces of dirt, grease or oil. This will give the crazy glue its best chance to hold tight. Good luck!
                                                                                                                                                               -- D

[rogertra]

I've used AC glue to fix the gears in Athearn Spectrum steam with great success.  And yes, clean everything really well first.

[electrical whiz kid]

I've had the same problem with one of my 2-8-0's, so carry on; I'll take all the help I can get.
Rich