# Replacing Rubber Band Drive and Motor in Old Athearn Train



## dchartier (Jan 29, 2015)

I obtained a beautiful, very old model of BART (the San Francisco Bay Area's electric commuter train) from Athearn. The powered car uses a motor with rubber drive belts (rubber bands connecting the drive shafts to the axles). To put it bluntly, this old train barely runs.

I'm not too thrilled about the rubber drive belts and would liked to replace the whole the drive train with a geared drive and new motor. Unfortunately, I have no experience in this area. What parts will I need to make this conversion? And can you point me to any resources that assist me in this project?

Many thanks!

Doug


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## traction fan (Oct 5, 2014)

*Bart repowering*

Doug;

I think you may need hands on help on this one. Is there a train store near you? If so I'd recommend taking your Bart car to them. I remember the drive system you're describing.
It was used on some early diesel locomotives. I had a B&O F-unit loco with rubber band drive.
As I recall, it ran quite smoothly. Have you checked for any binding in the drive shafts? Does the motor run well when disconnected from those shafts? If both are OK, and the wheel/axle assemblies turn freely then it may be a mater of just replacing the rubber bands with new ones.
You may be able to find them at an Office Depot, or Staples, store.
If you're set on getting rid of rubber band drive altogether, then you might consider replacing the whole chaises(everything but the shell) with a more modern loco mechanism.

Good Luck

Traction Fan


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## DonR (Oct 18, 2012)

Possibly the easiest way to upgrade the trucks on that
car is to look for a newer diesel loco frame with geared trucks.
You may have to trim the frame or add to it so the shell
will fit. Just remove the side frames from the trucks to leave the
wheels exposed as Bart car wheels are. 

If you are running DCC you'll want a recent year
vintage so that the motor doesn't draw too much
current for the decoder.

Don


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## dchartier (Jan 29, 2015)

Thanks, guys, that is helpful. I'm going to try to replace the rubber bands and see if that helps things. If that works and performance is acceptable, I may keep things as-is. We'll see.

As to the point on current draw of the motor and DCC, do you think it's likely the old motor in the BART would require too much current for a DCC decoder?


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## shaygetz (Sep 23, 2007)

1/2" rubber bands from Office Max will do the job...they run great once cleaned and lubed, mine is a super crawler. The A-Line/Ernst conversion kit when found, is pricey and simply not worth the extra money with the newer , more accurate models that have come out in the last few years.


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## dchartier (Jan 29, 2015)

Thanks. Today, I replaced the rubber bands with some cheap ones from Ace. After applying a little oil, the BART runs great at medium and high speeds, and I can crank it up pretty high. Low speed, as I expected, is pretty bad--a lot of stuttering and shaking. Any tips on improving low-speed performance?

I guess I'll stick with the OEM engine and band drive. I still plan on installing a DCC decoder with custom sounds of real BART trains and LED lights. Any issues I should expect or be on the look-out for with using DCC with such an old motor?


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## shaygetz (Sep 23, 2007)

It should slow down as it's worked it. Now run it real fast and stop...I just love that cartoon-like back and forth boing that they do... :laugh::thumbsup:


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## DonR (Oct 18, 2012)

By all means check the current draw of that motor.

Do a stall test. Connect one lead of the track circuit
in series with your volt/ohm meter set to amps (some 
require that you put the probes in a separate
jack), the other lead to the track. Place the
car on the track and run the speed control up to
about 10 volts as you hold the car from moving and
press down until the motor stalls. Check the meter
at that point. If it shows over 1 amp, it would
endanger a decoder.

If when you run it at a realistic slow speed the
meter shows half amp or so, it would probably
be alright for a decoder.

Don


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## dchartier (Jan 29, 2015)

Thanks, I'll try that tonight!



DonR said:


> By all means check the current draw of that motor.
> 
> Do a stall test. Connect one lead of the track circuit
> in series with your volt/ohm meter set to amps (some
> ...


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## DonR (Oct 18, 2012)

And, make a big note to self:

TURN METER KNOB AWAY FROM AMPS after the test.

It makes a lot of pretty sparks when you stick the
probes into a wall outlet if you fail to do that.

Who me? Yes me. I did it. 

Don


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## mikek (Dec 29, 2013)

For good slow speed operation have clean wheels, clean track, clean commutator. Consider a capacitor on the motor.


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## dchartier (Jan 29, 2015)

Thanks for all the advice, guys. Although the rubber band drive works okay, I've decided to replace it with a geared drive train. I found a well-priced frame and motor for an Athearn GP38. The dimensions aren't perfect--it's a little bit short, and the distance between the trucks is a little shorter than on the prototype--but I think it'll be acceptable upon casual observation. I'll let you know how it turns out.

Again, I appreciate your assistance!


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## jlassen (Dec 5, 2013)

*New frame for your Athearn Bart?*

Did you ever have any luck finding a suitable frame for your Athearn Bart cars?

Did you bother replacing the dummy frames, so as to get a consistent/more prototypical look?

Looks like I managed to score one, and I'm wondering how much effort/time/Money I will be putting into it. Given the suggestions in this thread, I suspect I will be looking for a full frame replacment withing seconds of it arriving...


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## dchartier (Jan 29, 2015)

jlassen said:


> Did you ever have any luck finding a suitable frame for your Athearn Bart cars?
> 
> Did you bother replacing the dummy frames, so as to get a consistent/more prototypical look?
> 
> Looks like I managed to score one, and I'm wondering how much effort/time/Money I will be putting into it. Given the suggestions in this thread, I suspect I will be looking for a full frame replacment withing seconds of it arriving...


Congrats on a good find!

I ended up doing a lot of custom work. For the powered car, I bought an old Athearn GP frame. I then lengthened it and removed the fuel tank in the middle. I cut the frame in half with a Dremel, then used brass stock to lengthen it to where the trucks should be. I added some styrene to the ends to make the total length of the frame the same as the shell. There is very little clearance between the floor of the frame and the top of the shell, so I bought a narrow diesel Athearn repower kit from Northwest Short Line (part # 1163-4). The motor and flywheels fit perfectly, and the motor is very quiet.

Attached are photos of the frame with and without the shell. Please forgive the janky wiring--I took these photos during the testing phase. Also note that since taking the photo of the BART with the shell, I've moved the trucks a little further out toward the ends. When you look at prototypical photos, you'll see that BART's trucks are very close to the ends of the cars.

For the non-powered cars, I lengthened a bunch of 40' Athearn Blue Box boxcar frames (I used 40' versions only because I had a bunch sitting around). I simply cut them in half and added styrene to the middle. These custom frames fit really well and are easy to work with.

To be honest, this project has taken a lot of my time--though mostly because this is my first time doing significant modifications to frames or drive trains. Nonetheless, it's been fun and a great learning experience.

Good luck! Please let me know what you end up doing.

Best,
Doug


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## JNXT 7707 (May 5, 2013)

dchartier said:


> ......Low speed, as I expected, is pretty bad--a lot of stuttering and shaking. Any tips on improving low-speed performance?


I have seen someone replace the original Athearn motor with a lower RPM can motor, and it made a dramatic difference in operation - slowing it down to realistic speeds while making it run nice and smooth. If I ever get around to picking up an old Athearn RDC that is the path I intend to take.


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