Bachman 2-8-0 lopping discovery

Discussion in 'N / Z Scale Model Trains' started by garyn, Aug 14, 2003.

  1. garyn

    garyn Member

    I have 2 of these engines, one works fine, the other has a problem. On the flat the lopping was not very noticable, but on the grade at slow speed it was VERY noticable. In addition it did not have the traction my other 2-8-0 does, slipping with as little as 4 cars on my 4% grade.

    I decided to investigate as to why it was "lopping."

    I had previously discovered that only the 2 middle driver sets are geared. The 1st and last driver sets are linked to the 3rd driver set with the side rods. Hmmm So I "lightly" lubed the siderods and driver axles. Improved it a bit, but did not eliminate the lopping.

    Tonite I discovered that on my problem engine, the engine sits on the 1st and last driver sets. The middle 2 geared driver sets are a "hair" above the rail. I discovered this when I slighly pushed the engine forward and backward on the rail. The 1st and last drivers would move, but not the middle 2 geared drivers. ah ha!!!

    This results in the gears drivers not having traction to the rail. And this explains the lopping action. There is no track contact for the geared drivers, only the siderod on the 1st and last driver set. Also this explains why this engine doesn't pull up my 4% grade, the traction tire on the 3rd driver set is not able to grip the rail.

    I also discovered that my engine is not even balaned on the 4 wheels of the 1st and last driver sets. It wobbles when rocked by hand, and visually I can see 1 wheel rock.

    The other problem was a clicking sound. There is a pin behind the sliding piston assembly (I need to learn the names of these parts) that sticks out a "bit" too far and will sometime hit the siderod of the lead driver. This might be the "thump" that others hear.

    While I don't like what I found, at least now I know the problem. I think this one has to go back to Bachman, as I don't have a mill to fix the frame, nor am I good enough for the fine machining needed to fix the wheel contact problem.

    Ah the limitations of N scale, and not being able to spring each driver wheel.

  2. tomgschilling

    tomgschilling New Member

    Bachmann 2-8-0's

    Gary, I've been planning to buy one of these as soon as I can get my hands on an unlettered version. Reports from folks indicate that some of them run perfect and some of them run...well, not so perfect. I'm not familiar with the term lopping. Can you enlighten? Thanks. ...Tom
  3. garyn

    garyn Member

    My other one runs just FINE. This one didn't :-( But that is not stopping me from planning to get at least 2 more Consolidations.

    I'm not sure if lopping is the proper term, but...this is when the wheel does not smoothly turn. Rather it get "pushed" or "pulled" in spurts by the siderod. So rather than the engine smoothly running, it would seem to move in jerks.

    This is one of those situations where running in a local hobby shop is needed. And important, you need to be on the throttle with your face down at the test track, not the clerk running it on a test track behind the counter.

    However, mine runs fine on level track, the lopping makes itself known on the grade. On level track if you are VERY observant, you can barely see the lopping. So even with a hobby shop test you may not detect it, unless the lopping is BAD.

    I emailed a store that listed "undecs" with a "reservation" and they said Bachman will be doing a rerun on the undecs with an estimated Nov delivery.

    If you can erase or strip the lettering, it looks like you can get some pretty good deals on the Spectrum Consolidations.

  4. davidstrains

    davidstrains Active Member


    I found that 1 of the 3 that I have had a traction tire that had slipped off the wheel. Putting that back on cured the wobble.
  5. n_gineer

    n_gineer New Member

    Could it be possible that some of these engines need quartered? i know from building H.O. engines that being a little out of alignment can cause binding of the drivers. severe binding and the engine won't run, very slight binding and it runs in a jerking manner.
  6. rich maiorano

    rich maiorano Member

    Just send it back to bachman and they will most liking give you a new engine have two my self also check to make sure the wheels are in gauge too one of mine use to hop:D :D :D Rich
  7. garyn

    garyn Member

    The 2-8-0 will be going back. :-( Along w an F7 that is slipping its gears.

    Regauging the wheels was done early. Most things won't run on my layout w/o the wheels being regauged to spec.

    It "might" be out of quarter, but I don't have anything to check quartering, and I can't figure out how to remove the bottom gear cover w/o breaking it. But unless the rear driver is made level so the geared drivers will sit on the track, the quartering really does not make much difference.

  8. tomgschilling

    tomgschilling New Member

    Bachmann 2-8-0 Lopping

    Gary, I hope you keep us posted about your experience with returning the 2-8-0. I'd sure like to know the outcome. ....Tom

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