Model Railroading > Athearn BB GP 40-2 Qustion

I have an old Athearn BB GP 40-2 that I want to update the drive on. Will the old BB GP 40-2 shell fit the newer Athearn GP 40-2 drive?

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Probably easier to replace the motor with a Genesis motor. Athearn does sell them seperately. Comes with flywheels and circuit board installed.

I agree with just replacing the motor.

On a separate note, this is a beautiful model! Well done sir.

Jack Pappas
Spokane, WA

Consider replacing the wheels as well, the old sintered metal wheels (basically pressed metal fragments) are clunky old tech that collect and distribute grime. Clean up the old lubricant in the gear assembly, should work well.

The downside is the old frames carry electrical current, sometimes there is trouble across two locomotives.

Nice weathering job.



Edited 1 time(s). Last edit at 12/14/18 10:39 by TCnR.

TCnR Wrote:
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> Consider replacing the wheels as well, the old
> sintered metal wheels (basically pressed metal
> fragments) are clunky old tech that collect and
> distribute grime. Clean up the old lubricant in
> the gear assembly, should work well.
>
> The downside is the old frames carry electrical
> current, sometimes there is trouble across two
> locomotives.
>
> Nice weathering job.

Not if you use kaydee coupler pockets. 

EL-SD45-3632 Wrote:
-------------------------------------------------------
> TCnR Wrote:
> --------------------------------------------------
> -----
> > Consider replacing the wheels as well, the old
> > sintered metal wheels (basically pressed metal
> > fragments) are clunky old tech that collect and
> > distribute grime. Clean up the old lubricant in
> > the gear assembly, should work well.
> >
> > The downside is the old frames carry electrical
> > current, sometimes there is trouble across two
> > locomotives.
> >
> > Nice weathering job.
>
> Not if you use kaydee coupler pockets. 

And nylon screws too.

PHall Wrote:

> > Not if you use kaydee coupler pockets. 
>
> And nylon screws too.

 If one uses the Kadee provided coupler boxes you don not have to use insulating screws as the boxes will completely isolate  the metal coupler from the frame attachement point.

best regards,
Mark G.

MarkG Wrote:
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> PHall Wrote:
>
> > > Not if you use kaydee coupler pockets. 
> >
> > And nylon screws too.
>
>  If one uses the Kadee provided coupler boxes you
> don not have to use insulating screws as the boxes
> will completely isolate  the metal coupler from
> the frame attachement point.
>
> best regards,
> Mark G.

I believe in taking no chances. Nylon screws are cheaper then DCC decoders.

I always build up a pad behind the pilot and body mount the couplers. Attaching the kadee boxes to the frame sets them to high.

Posted from Android

Back in the BB days, I started body mounting couplers to eliminate snow plow or coupler removal when removing the chassis. Most of my old models are equipped with the old “Emrex or Emerex” lighting circuits for both constant bright headlights and the prime rotary beacon effect. A few of these models, like this GP40 are worth changing over to DCC, but this particular model also has a lame truck.



Edited 1 time(s). Last edit at 12/15/18 14:14 by KM-ML4000.

KM-ML4000 Wrote:
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..., like this GP40 are worth
> changing over to DCC, but this particular model
> also has a lame truck.

Some of the recent Athearn 6 axle frames can not swap between shells even though simple logic would say they should be able to. I called Athearn and they were very informed on what could swap and what could not. In my case apparently the frame casting/milling was shaped differently between runs, there are protrusions or tabs that either add weight or are used for speaker, or lighting mounts that sometimes interlock with the shell. It appears that design idea has passed but that's what the issue is/could be. There's also less complex issues like removing or adding around the coupler mounts, not to be confused with the interlocking design.

Suggest calling Athearn and asking a fairly detailed question. Some of the info is also hidden in their parts page as well.

+ btw the current C-truck design does not fit on the older frames, the older trucks are not in stock. Not sure if the B-truck design went through the same iteration or not. The C-trucks were re-designed for seperate feeders for the two rails/polarity with an isolated frame, better but not backward-compatibile.



Edited 1 time(s). Last edit at 12/15/18 13:22 by TCnR.