Repowering a Doodlebug (Bachmann)

[Ed Kapuscinski]

You know what would make that thing Pennsy as frig? A porthole door.

[randgust]

And that would qualify you for the PRR Congressional model of Dishonor.  Badump-thump.

[Lemosteam]

Hang onto this model, as I have planned for a long time (idea from @VonRyan 's) to develop a PRR font end cut & shut conversion for the Bachmann shell.

Maybe a 2019 offering.

[up1950s]

Hang onto this model, as I have planned for a long time (idea from @VonRyan 's) to develop a PRR font end cut & shut conversion for the Bachmann shell.

Maybe a 2019 offering.

How about a Sperry shell that roamed PRR rails ?

[randgust]

The NE railfan site has a wonderful collection of photos of doodlebugs.
http://www.northeast.railfan.net/self_prop4.html

There's a lot of photos of the PRR ones out there.   What I noticed was that the earliest ones (one that went to PRSL) look a lot more like the stock Bachmann, and are 'probably' the oldest lot that did a one-year stint on my line.
It's not an exact match, but it's stated 1925, ex-PRR, and other than I can't prove it, is probably what ran on my line in 1926:
http://www.northeast.railfan.net/images/prsl_brill0.jpg

The later ones - 1927-28 and later, yeah, that's what you think of as being a PRR design, high arch roof, features that only an SPF could love.  1930 build so it wouldn't be what would have run on my line:
http://www.northeast.railfan.net/images/prr4668a.jpg

There's photos of 4668 in Olean NY, but without the end doors, so that's another thing.
I have noticed that the design evolution of these over a five-year period usually included roof-mounted radiators and in general looking a lot more heavy duty, particularly in the trucks.   I'm thinking that the early ones must have had some real cooling issues.

[brokemoto]

Oh, I just had to look that one up because I couldn't imagine what that would look like.   Holy CRIP...And yeah, they towed it around with an RDC.

You found the car.  It looks like it is in a locomotive hauled train in that photograph..  I am guessing that the thing to which it is coupled is not a doodlebug, as I do not see a door,

There was a photograph in Classic Trains of CRI&P Train #15.  It was taken on a cold day.  It had an FM road switcher for power, some HWs, a LW an RDC-3 and another LW.  No, that was not a typographical error.  There was an RDC-3 MID TRAIN.

I must wonder if:

They ran the RDC in Georgia Overdrive until it split from the train and continued to its terminal

The shops added pass-through steam lines so that the car behind it could be heated.

[Tom L]

Speaking of the Rock Island, here's another doodlebug on my list. One of the shorter Tomytec chassis should fit nicely. The shortest bugs ever maybe (they had several of these)? Imagine one of these pulling that boat tailed combine!

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Tom L
Wellington CO

[brokemoto]

The shortest bugs ever maybe (they had several of these)? Imagine one of these pulling that boat tailed combine!

It looks like little more than a boxcab diesel with a baggage section that has messenger windows.  The Q baggage/mail is interesting to  note, as well.  Was it rented or was this a joint Q/RI local?  Joint locals are unusual.

[DMetz]

Randy, back to your Doodlebug build, I have a couple of questions.  I know you used that Tomytec chassis because you had it on hand.  If you had to buy all of the parts, would you do it the same way?  I am curious why you powered the rear truck, instead of just removing the gears and making it non-powered.  There is not really a need for the extra pulling power.  Does the extra powered truck make the unit run smoother?  I am looking into repowering an older doodlebug, and I was thinking about just replacing the front truck.  The single powered truck chassis would fit in with little modification.  I was going to use the original doodlebug rear truck just for electrical pickup.  I was afraid of the longer drive shaft causing problems on 12 inch radius curves.  But with an offset gear tower, there should not be binding problems.  Did you have to modify the interior for clearance to the longer driveshaft? 

Dan

[randgust]

I've used the TM03 chassis in my Whitcomb for years, and they're pretty good with one-truck drive.  As a locomotive they really have to have a traction tire and a lot of weight over that drive truck.  With end-axle pickups they are very free rolling.   The short-wheelbase 12mm trucks have a rider plate on the interior axle though and doesn't roll quite as easily.   With 14mm trucks and end-axles I'm not sure I'd care, but with these trucks yeah, I'd prefer to power both.   And taking the traction tires off entirely really improved the pickup.

But I've always found that if you can power axles on anything you should.  And extending the drive shaft is one of the easier parts of the project.

Bachmann's method of pickup with the non-flexible plate wiper on the frame on the original truck is actually fairly poor.  Didn't like that at all.   And the white axle centers cracked on mine, so much for that.

I did a test tonight on running my finished chassis on a 9 3/4 curve and it went around it without noise, complaint, or slowing.  That's what putting the universal right over the truck center gets you.

I popped the interior seat insert out, cut out the center aisle, and looked at gluing the seats to the interior frame edge to clear the driveshaft and pickups.   It probably would have worked but I decided that without interior lights, it wasn't worth it and I left it out.

So do I think it would still work?  Yes, probably.  Would I do it this way again?  Yes.   Figure worst case you start with a TM23, try the one truck drive design, if you're not happy with the results, put the gears back in and extend the driveshaft.

[up1950s]

That RI unit would make a great MOW critter .

[DMetz]

Randy, Thank you for your detailed reply.  That answered a lot of questions.  I am looking at the Erie doodlebugs for my prototype, and they have a truck axle spacing of 7' 6".  So the 14 mm Tomytec trucks will be better.  I am looking at the TM16 chassis as a start.  I think your method of extending the driveshaft could be easier than trying to remove gears from the rear truck.  And it gives more power anyway.  I found a reference that shows the minimum radius is 5.5 inches for all of the longer Tomytec chassis.  The only thing I need for the Erie doodlebug is a Stillwell style roof. 

Dan

[Lemosteam]

Randy, Thank you for your detailed reply.  That answered a lot of questions.  I am looking at the Erie doodlebugs for my prototype, and they have a truck axle spacing of 7' 6".  So the 14 mm Tomytec trucks will be better.  I am looking at the TM16 chassis as a start.  I think your method of extending the driveshaft could be easier than trying to remove gears from the rear truck.  And it gives more power anyway.  I found a reference that shows the minimum radius is 5.5 inches for all of the longer Tomytec chassis.  The only thing I need for the Erie doodlebug is a Stillwell style roof. 

Dan

s

Dan, send me a PM regarding the roof.

[delamaize]

Ok, My turn for Repowering my doodlebug.

I did a few things different from Randgust, But I still had outstanding results!!

Picture before I started fitting the body.
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Here is a picture of the body attached, during my run testing. I lost one of the bachman truck sideframes along the way sometimes, so I am stuck using the ones that came with the chassis. It still needs to be painted, but I am pretty happy thus far with it!!
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(No Idea why it's upside down, If a mod can fix it, that would be awesome.)

Very short video. I still need to dial in the CVs. It has a nice low speed, and pretty good control, but rocket top speed. Taken on the Kitchen Counter and Southern. I don't have a layout ATM.

[ksmiley]

So which chassis did you use.