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Stewart/Kato F3B to F3A + DCC? Locos and rolling stock
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New member 11 posts AndersE New member 11 posts
AndersE
Hi, is it possible putting a Stewart/Kato F3A body onto a F3B chassies? Don't have parts that I can check. Is it difficult adding DCC and sound? Any drop in solution? /Anders
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Joe Atkinson IAISfan Super User 3,774 posts
Joe Atkinson IAISfan

DCC and sound

I've only used the Stewart/Kato F-units for drive donors for my P2K Geeps, so I don't recall the details of the A vs. B frames.  However, the DCC/sound install in those repowered Geeps - which are essentially Stewart/Kato F's in a different frame - was no more difficult than any hardwired DCC install.  Also, you'll have an easier time than me given that the Fs have more room in the shell for the decoder and speaker.  I used a Tsunami decoder and Railmaster speaker.

Edit:  As Chris correctly pointed out below, my statement about having more room in the F-unit shell is inaccurate.  I've done away with the leftover Stewart/Kato F frames and shells I used as donors for my projects, but I believe the frames extend well up into the shells, leaving little room for the speaker (and perhaps capacitor?) without milling.

Joe Atkinson
Modeling Iowa Interstate's 4th Sub, May 2005
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Larry of Z'ville Frequent poster 984 posts
Larry of Z'ville

They are identical in dimensions

The A's have the head light circuit and a tube to focus the light. The drives are otherwise common. They are dimensionally the same on the F3. F7 and F9 units. The differences in the models are all tied to the shells. The drives are great. Good Luck, Larry

So many trains, so little time,

Larry

check out my MRH blog: https://model-railroad-hobbyist.com/node/42408

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Chris Palermo patentwriter Frequent poster 970 posts
Chris Palermo patentwriter

DCC straightforward, not sure about sound

I have a stock Stewart F unit on my workbench right now with a non-sound DCC install half done. As Joe said, it is a straightforward hard-wired installation; it requires insulation (isolation) of the motor brush contacts, 6 soldered joints, and replacement of the stock bulb with an LED or 1.5v bulb and resistor. A one hour job, if you have all parts and have done similar ones before. However, I see no room for a speaker on a drop-in basis so I'm not attempting sound. To do it would require extensive milling of the chassis.

To achieve sound, I was thinking of close-coupling a dummy B unit (which I have) and putting the speaker in there.

Chris

Christopher J. Palermo

Mountain View, CA
At Large North America Director, 2024-2027 - National Model Railroad Association, Inc.
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RGB600V Active Member 53 posts
RGB600V

A-unit vs. B

Anders:

FWIW, I bought a pair of Stewart FTs, an A & a B, with just the A-unit powered. I wanted to put sound in them both plus power the B-unit. I found that the B-unit frame is not as high as the A-unit's-- it only goes about halfway up to the roof-- so that made it much easier to add a decoder & speaker. I installed a B-unit frame in the A unit & ended up with both units powered using the old LC-101 Soundtraxx decoders. So if you want to put sound in your F3s, I'll bet you can put a B-unit frame under the A-unit & have more room for the decoder & speaker, without having to saw off the top of the frame. Or maybe you could put sound in the B-unit & a regular non-sound decoder in the A? They would have to run as a Consist but that's not hard to set up. Good luck!

Bob Battles
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