These were only produced for a few years and I think I know why. It seems it has a serious design flaw. I purchased one on ebay last year and intended to put it into service on my branchline. When I went to test it out I discovered it uses a belt drive motor. The problem is the small rubber band that is used for a belt slips badly preventing the bug from running smoothly. I tried replacing this band but the problem persists. I realize Bachmann also has made a doodlebug but I prefer the Walthers model because it is shorter and better suited for the smaller radii that I have on my branchline.
It seems to me the solution is to replace the motor and front truck with a gear driven assembly but have no idea where to even begin looking. Can someone recommend a replacement motor/truck for this doodlebug?
John-NYBWCan someone recommend a replacement motor/truck for this doodlebug?
The only thing I can suggest is an NWSL Stanton drive.
https://nwsl.com/collections/ho-stanton-drives
I don't have the Walthers Doodlebug but I did have one of the older Sperry rail cars that had the belt drive. These were later redesigned to use a fully-engaged gear drive.
To use a Stanton drive you would have to carefully measure your present wheelbase on the doodlebug and order the closest replacement. Then figure out how to fit everything, including the truck sideframes.
There are application notes here for the Stanton Drive:
https://cdn.shopify.com/s/files/1/0250/4032/2669/files/Power_Drive_2.pdf?263
Here's a photo of both types with the belt drive above and the gear drive below:
SRS_123b by Edmund, on Flickr
I do not know if later runs of the Walthers gas-electric Doodlebug had a similar drive modification. Possibly the drive from a later-run Sperry car could be used?
Good Luck, Ed
gmpullman John-NYBW Can someone recommend a replacement motor/truck for this doodlebug? The only thing I can suggest is an NWSL Stanton drive. https://nwsl.com/collections/ho-stanton-drives I don't have the Walthers Doodlebug but I did have one of the older Sperry rail cars that had the belt drive. These were later redesigned to use a fully-engaged gear drive. To use a Stanton drive you would have to carefully measure your present wheelbase on the doodlebug and order the closest replacement. Then figure out how to fit everything, including the truck sideframes. There are application notes here for the Stanton Drive: https://cdn.shopify.com/s/files/1/0250/4032/2669/files/Power_Drive_2.pdf?263 Here's a photo of both types with the belt drive above and the gear drive below: SRS_123b by Edmund, on Flickr I do not know if later runs of the Walthers gas-electric Doodlebug had a similar drive modification. Possibly the drive from a later-run Sperry car could be used? Good Luck, Ed
John-NYBW Can someone recommend a replacement motor/truck for this doodlebug?
Thanks, Ed. That looks very similar to the interior of my doodlebug. I wouldn't be surprised if they used the same mechanism originally. That later Sperry motor looks like it might be the answer. Walthers doesn't list either the doodlebug or the Sperry car on their website so it looks like ebay is the best bet.
Yeah, the Stanton drive runs about $100 so it really isn't an economically reasonable solution.
I still have my original, belt drive Sperry car. You're welcome to it if you think the parts may help your EMC gas-electric car. I just test-ran it and it still runs pretty well after some fifteen years (or more?) original belt!
Maybe the motor/truck parts are interchangeable with the doodlebug.
Send me a PM if you're interested.
Regards, Ed
All the way down on the hoseeker walthers page they show some power trucks that resemble what you are looking for (u776/777/778). Maybe that will help in your search. Hope this is helpful.
I'm not familiar with the doodlebug under discussion, but I built one of my own from a Rivarossi combine, along with part of the frame from an Athearn F7, and one of the geared trucks that was part of that loco. I used the Athearn driveshaft parts and hooked it up to a Mashima can motor that I had on-hand.
To make it look a little less EMD-ish, I put Detail Associates' C-Liner sideframes onto the power truck.The rear truck was one from the combine, but I put metal wheels in it and wired it to also provide current for the motor....(Click on the photos to enlarge them)
...I used just enough of the F-unit's fuel tank to represent one suitable for a doodlebug...
I also added quite a bit of weight to it, as my layout has lots of grades. It tips the scales at 21oz., although I've never bothered to see how much it could pull. Its usually train is a couple of Athearn coaches, and maybe an express car or two, and even with only one powered truck, it easily pulls them up a twisting 45'-long 2.8% grade (uncompensated).
I don't know if there's room in your doodlebug for such a set-up, but it was very easy to do. I have another Athearn power truck, along with the rest of the underframe, too, and will eventually put them into a Model Die Casting Harriman combine...always good to have a back-up.
Wayne
I'll keep this in mind as an option. I have several old Athearn BB F7s just gathering dust on the shelf. I looked at several of my old diesels including a Model Power switcher that was part of a trainset that got me back into the hobby way back in the 1970s.