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 Posted - June 16 2009 : 4:50:36 PM
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I am contemplating some HO Athearn diesel unit tinkering, in particular the 8 wheel units.
I have been told that the same motor/flywheel set up will go in the U28B, U30B & U33B, as well as the GP9, GP35, F7A, F7B & a few other Gp's.
What I am wondering is if there is any commonality of the chassis/gearbox/wheels among 8 wheel models?
For example, if I pick up an old U33B & remotor it, can I drop a U28B body on the result??
Or put together other Athearn 8 wheeler body/chassis combinations??
Thanks
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Posted - June 16 2009 : 5:45:51 PM
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The U33B and U28B use the same chassis.
There are some differences in earlier and later productions. The best way I have found is to study the part diagrams and compare part numbers.
http://www.hoseeker.net/athearnmicellaneous.html
Ray
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Posted - June 16 2009 : 8:13:50 PM
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quote:The U33B and U28B use the same chassis.
There are some differences in earlier and later productions. The best way I have found is to study the part diagrams and compare part numbers.
http://www.hoseeker.net/athearnmicellaneous.html
Originally posted by Ray Marinaccio-June 16 2009: 5:45:51 PM
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Thanks Ray
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Posted - June 17 2009 : 4:42:09 PM
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Commonality? That's how Athearn kept the costs down!! It's one of the great things about the blue-box locos. Athearn tried to keep the number of common parts as high as possible which reduced manufacturing costs.
With regards to the 4-axle GEs, the 28, 33 and 36 all share a common mechanism. Frame, trucks, motors, flywheels, etc are all interchangable. Take any of those shells and they will fit the basic frame. The older frames do NOT have the frame cut out for flywheels though. A rebuild I like to do is to drop an old Bachmann 4-axle GE onto the Athearn frame. Its actually a very simple job.
Also, if you get any of the Athearn 4-axle switch engines, (S12, SW-7, SW-1000 and SW 1500), they also share a common frame/mechanism. Be careful as the switchers are the only locos that use the smaller motor. I think it's 1/2 inch armature while all the others use the larger, 5/8 inch motor.
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Posted - June 21 2009 : 1:24:16 PM
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Just the topic for a few questions I have regarding a current project of mine. To wit: I have an Athearn "U-boat" shell lettered for the original Auto-Train. I like to make a working locomotive out of this shell, however there are challenges.
1. The Auto-Train locomotives were U36b's with EMD Blomberg trucks ala' host railroad Seaboard Coast Line's practice. Would an Athearn GP35 frame and trucks fit this shell?
2. Assuming I will find an appropriate frame and trucks, I'd like to improve the running/pulling ability of a standard "blue box" locomotive. I recall an aftermarket motor called the "Helix Humper" from years past. Is this motor still available and is it worth the hype?
3. Any tips on making this locomotive DCC friendly?
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Posted - June 21 2009 : 4:04:16 PM
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quote:Just the topic for a few questions I have regarding a current project of mine. To wit: I have an Athearn "U-boat" shell lettered for the original Auto-Train. I like to make a working locomotive out of this shell, however there are challenges.
1. The Auto-Train locomotives were U36b's with EMD Blomberg trucks ala' host railroad Seaboard Coast Line's practice. Would an Athearn GP35 frame and trucks fit this shell?
2. Assuming I will find an appropriate frame and trucks, I'd like to improve the running/pulling ability of a standard "blue box" locomotive. I recall an aftermarket motor called the "Helix Humper" from years past. Is this motor still available and is it worth the hype?
3. Any tips on making this locomotive DCC friendly?
Originally posted by detroitterminal-June 21 2009: 1:24:16 PM
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The only thing I personally can tell you is that the Helix Humper is still available:
http://www.alliancelink.com/alp/
    
- Matt -
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Posted - June 21 2009 : 5:05:23 PM
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I'm almost certain that the U boat shell will not fit the GP35, or any of the Geep frames. Which ones are compatible; I don't know.
For pulling ability, you might try going with the nickel silver wheels and an Ernst re-gear kit. Regearing will definitely reduce the cruising speed of your loco. And you can add lead weights to the shell.
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Posted - June 21 2009 : 5:13:46 PM
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Here is a link that shows the locos with the same dimensions:
http://www.hosam.com/
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Posted - June 22 2009 : 12:38:18 AM
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Altering your U-boat should be quite simple.
Trucks:
You can replace the GE trucks with a set from a GP35. However, there are a couple ways you might consider as well. Does your U-boat have metal or plastic truck side-frames? If plastic, then swap the side frames with a set from the GP7/35/F-unit. The newer trucks come with plastic side frames that just press fit. If it is the metal side frame, you will need to replace the whole truck, in which case, you can use the newer GP7/35/F-unit trucks. But which ever truck you use, you can not swap the U-boat frame with a GP35 frame.
Pulling/running:
How much work/money do you want to put into this project? Adding balanced weight will improve pulling power. The more weight you add, the more pulling power improves... to a point. Add too much weight and you burn out the motor. If you stick with the stock motor, you should be able to ballast the loco up to 20-22oz with no motor problems. But I wouldn't go higher then 16-18oz with most aftermarket can motors. But even a 16oz, 4-axle U-boat should be able to pull a large number of cars!
The stock Athearn motor is very easy to improve. The main point is to polish the commutator to a mirror finish. This is easy with a Dremel tool and some fine sanding films. I would try to improve the stock motor before investing in a can motor. Does your loco have flywheels?
DCC friendly:
Yes, you can make the loco DCC friendly. You need to insulate the bottom motor contact from the frame. Then wire that contact directly to the trucks. Or, you can replace the stock motor with a can motor and still add the wireing from the motor to the trucks.
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Posted - June 22 2009 : 12:38:49 AM
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The EMD and GE trucks locate over a kingpin on the frame, so the EMDs should be a direct swap. The wheelbase is the same, and the EMD brake shoes only extend a hair further on each end than the GE trucks.
If you have some of their newer Blue Box 2 axle trucks, all you'd have to do is swap the sideframes. Regearing isn't necessary if you're installing a good motor like a Helix Humper, or even just tuning up the original. Their gearing was quite good.
Here's a handy Athearn tuneup guide:
http://www.mcor-nmra.org/Publications/Articles/Athearn_TuneUp.html
The Tyco Depot
Edited by - NickelPlate759 on June 22 2009 01:19:25 AM
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Posted - June 22 2009 : 12:49:27 AM
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| That link should provide everything you need to do to get a smooth running Athearn motor!!
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Posted - June 22 2009 : 01:22:34 AM
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Yup, and Ray has a tutorial somewhere on 2 Guyz for tuning up the older units with the metal trucks.
The Tyco Depot
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Posted - June 22 2009 : 2:38:59 PM
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| Thanks folks! I appreciate the technical advice.
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Posted - June 23 2009 : 2:56:24 PM
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Yeh fellas, I appreciate this info too.
Alco Fan
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