Bachmann Plymouth WTD switcher

[Cajonpassfan]

I never paid much attention to this clunky old model, but according to Spookshow, the latest mechanisms and power pickups are quite good. Could anyone here who owns one please measure the axle spacing and wheel size for me?
Assistance would be much appreciated!
Otto K.

[narrowminded]

Looks like 21mm/ .826".  Equal distance between axles.  I couldn't get to the exact axle positions but that should still be pretty good, like .005" or better.  And .291" wheels  (rounds to 46").

[Cajonpassfan]

Oh wow, that was quick!! Sometimes you do have to love the Internet (and the people here).
Thank you!!
Otto

[narrowminded]

Just added wheel diameter.  Mine is a pretty reliable runner albeit a bit fast. 

[Chris333]

New ones with the can motor run well. And Trainworld has them for $19. 

[Cajonpassfan]

Thanks, appreciate that, and thanks for the additional dimensions. And I did know about the price, that's what initiated my inquiry...can't beat that!

I was actually thinking of using a pair of them under a six-wheeled powered tender.
Several problems with that: the 11' wheelbase is a bit long for what I had in mind, but I could perhaps live with that. The wheel diameter is too large. Do you suppose one could replace the wheels with 36" or 33" Foxes?

Is the switcher inside or outside bearing? I'd need to whack off the sideframes and replace with appropriate truck frame castings, so an inside bearing mech would be much preferred. And then of course, there is the challenge of making the two mechs swivel enough to work through turnouts and curves...  Thoughts?
Thanks guys!

Otto K.,
who needs yet another new project like a hole in his head

[Chris333]

Sideframes are cast with the frame sides. I milled mine off. You could mill away more and be able to see the wheels. The wheels are flat faced:

[Cajonpassfan]

Oh wow, yes, thank you Chris. From the side view on the left, the intermediate gear looks like it's barely above the railhead, so putting smaller wheels on these axles is probably impractical. And the wheels it comes with are way too big for a tender. Well, I have enough on my plate already...

Thanks again, I think you may have saved me from myself, and forty bucks
Otto K.

[narrowminded]

Sideframes are cast with the frame sides. I milled mine off. You could mill away more and be able to see the wheels. The wheels are flat faced:

Yes, but the power pickups are a strip that runs across the face of all three wheels just inside that frame, contacting the flat wheel face for pickup.  Milled thin, sure.  Removed will need a new pickup scheme.

[Chris333]

No wipers on either of mine. They have split axles and the axles sit in frame slots.


These are both the newer versions with can motors. Here is one running:

[narrowminded]

Mine is probably a good five years or more old.  I'm guessing an older one.  Here's a pic where you can make out the strip. [ Guests cannot view attachments ]

[Chris333]

The whole frame must of been changed. You can see an open area above the worm and the square open frame motor:
http://www.spookshow.net/loco/bachmdt.html
Mine are closed on top and you can see the new can motor peeking out.

[narrowminded]

I think the general appearance of the frame is the same, jutting up into the cab and all, but the internal dimensions for the can motor probably did change. 

[Lemosteam]

Oh wow, yes, thank you Chris. From the side view on the left, the intermediate gear looks like it's barely above the railhead, so putting smaller wheels on these axles is probably impractical. And the wheels it comes with are way too big for a tender. Well, I have enough on my plate already...

Thanks again, I think you may have saved me from myself, and forty bucks
Otto K.

Otto, what diameter wheels are you looking for?  Looking at Chris's pic above, I would guess that you could mill 0.030" on the raduis befor the gear OD is at raalhead height.  That would put the wheel diameter at 36.96" 1:1.

This is a really great idea for a power tender under $40.

Now getting them to pivot, well that's a whole different story...

@Chris333 what is the OD of the gear on the axle?

[Cajonpassfan]

John, preferably 33's, could do with 36's as some of the 20K gal ATSF tenders had 37" wheels. But I don't think that can be done without replacing not just the wheels, but the whole shebang, wheelsets, gears, and gear train.

As to making them swivel, at least in theory it wouldn't take much on my 18" minimum curves. The wheelbase would be short so I thought I could get away with the front unit fixed and the trailing unit hinged to swing slightly side to side, kind of like a very short model Mallet running backwards... But it appears moot anyway.
Otto K.