Dumbing down a Bachmnn GP50

Discussion in 'Scratchin' & Bashin'' started by Herc Driver, May 14, 2007.

  1. Herc Driver

    Herc Driver Active Member

    I bought a Bachmann GP50 that I'm trying to turn into a dummy engine to pull behind like diesels. I already had an older model that I pulled the motor and drive rods/worm gear out of and it pulls fine behind a GP38. This new GP50 won't be pulled except for the strongest of motors (SD70 and such). Could too much grease in the wheel assemblies be dragging it down too much? I've cleaned it as well as I could, removed the gearing and motor, and it's actually lighter than the older GP50 that glides well.

    Any ideas?
  2. Nomad

    Nomad Active Member

    Do the trucks roll freely? Can you push them down the track with light finger pressure? If not the bearings or what holds the axles are to tight and putting a drag on the axles.

  3. Herc Driver

    Herc Driver Active Member

    Very good idea...and unlike it's twin (the other GP50) this model came heavily greased. I removed the gearing and each wheel will move but not "free wheeling" like the other GP50. I cleaned as much grease as I could without soaking in a solvent, but still it won't move freely after being pushed along the rails...in short...it won't roll by itself after a push. The metal frame is a bit heavy, but again, no heavier than the other unit which does roll freely after a shove down the rails. The only thing I can think of is the heavier weight grease used is causing too much resistance where the axles touch the trucks. I've also checked the wheel spacing and it meets standards. I had hoped to run a three unit lash-up of a GP38-2 and these two GP50's...but I'm not giving up yet. I guess the only idea left is soaking the wheel sets in a solvent to remove some of the grease build-up, unless there's some other ideas out there.
  4. doctorwayne

    doctorwayne Active Member

    I'm not familiar with the exact set-up of those locos, but did you remove the gears from inside the trucks? All that should be left inside the trucks is the axle gears: all other gears are just added drag, especially if they've been heavily greased.
    Many years ago, I bought two of the locos pictured below, via mail order, mainly because they were the first model RS-11s that I had ever seen. Built by LifeLike, (Proto-no-thousand):wink: they had a motor mounted vertically on the lead truck, and cast-on handrails that scaled out to about 6"x6". Starting speed was about 60 scale mph, with a top end around 200, when they ran. I removed the motor and gears, then did a bit of detail work, and gave them a paint job. If I had more interest in running diesels, I'd put them on powered Atlas chassis'. They're the only dummy units that I own.

  5. Squidbait

    Squidbait Recovering ALCO-holic

    It sounds like the axles are binding in the truck castings. Check to make sure there's no flash or excess plastic rubbing against the axles or the back of the wheels. Did you leave the brass contacts in for electrical pickup? They could be causing enough friction to slow it down too.

    You could try replacing the Bachmann wheelsets with JayBee or NWSL ones on a steel axle, they might work better.
  6. eightyeightfan1

    eightyeightfan1 Now I'm AMP'd

    Another thing is try adding back the same amount of weight you took out.
    You could use wheel weights you buy at any auto parts store. Or even pennies work.
  7. Bones

    Bones Member

    One thing that I have personally done...

    Make sure when you put the frame halves back together when installing the truck, that you put the plastic spacers between the frame halves. Also don't over tighten the screws. In a lot of bachmanns it's possible to over tighten the screws (sometimes with the spacers installed), and cause the truck to bind.

    Probably not what's going on here, but I've had it give me headaches in the past.
  8. Herc Driver

    Herc Driver Active Member

    GREAT ideas guys thank you and I'm going to check each of them out!

    I did remove all the gearing from the trucks, the motor, drive rods and gearing above the trucks too. The only thing in the trucks are the wheels. On the outside of the trucks, the brass contacts are still attached and I might have to remove them or at least bend them from touching the inside of the wheels. The frame halves allow the trucks to freely rotate with no binding and the plastic spacers are in their correct place. My last idea is to remove all the heavy grease that Bachmann placed everywhere and add some light weight sewing machine oil. I'm beginning to think that the heavier grease is causing too much resistance for the running diesel to overcome. Thanks again for the great ideas. I'm going to look into each more closely and see what works.

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