How to repower a Bachmann HO DD40X (now with video!)

I finally finished repowering my old Bachmann DD40 with a better mechanism.[:D] Now that it’s done and working, I thought I’d post a “how to” topic on how I repowered it.[:D]

The original 4-wheel-drive mechanism was a poor runner, no matter how much I did to make it better (it does run a little better than before, but still not great). I decided to repower mine with Athearn trucks and a pair of good quality (yet inexpensive [:D]) Mabuchi motors with flywheels.

I had to completely cut out the sections of the frame where the old trucks were mounted, and make separate frames for each truck, kind of like an old Mantua diesel. The motors are mounted on each end of the fuel tank, using flipped over A Line stick on weights, which are glued to the frame. The tape on the bottom of the weights is the same as what A Line sells for motor mounting, so you don’t have to worry about the motors coming loose.

I used parts cut off from the Bachmann sideframes and some extra brake cylinders to detail the Athearn trucks. It still doesn’t look quite like the DDA40X trucks, but it’s close enough to look good. You can also see what the home-made front truck mount looks like in the picture. All the Athearn wheels were replaced with NWSL 40" wheels, which roll quieter, look better, conduct electricity better, and grip the track more.

good job!

all my old pancake versions were retired long ago, replaced by the spectrum version, but if I run across any more, I’ll know how to update them.

Darth, you are the man when it comes to taking on unusual projects. Most people wouldn’t have the skill or desire to make a pretty poor running model work better but you really have a touch with this. It would be great to see a video of this behemoth in operation. [:)]

Great artical! You made the owner of the peel-and-stick weights factory very happy!

David B

Darth,Good job! Its nice to hear there are those that still like to tinker around improving drives and re-powering less then stellar performers.[tup]

Great! So maybe you can do that with some of my old locos…[:D]

Thanks everyone for your kind comments.[:D]

One thing I forgot to mention earlier is that the DD40 can only make it around a minimum 22" radius, instead of the 16"? radius the old drive could go around. Of course, most of you would want to run an engine this size on larger curves anyway, so I guess it doesn’t matter too much.[:D]

Working on things so they’ll run better is one of the things I like doing in this hobby.[:D] Tonight, I just finished making my new AHM Big Boy run fairly smoothly.[:D] The boiler mounts had a LOT of slop in them, and it could hardly do anything without wobbling all over the place.

That looks great!! I seem to remember that somebody was making an upgrade/repowering kit for the Bachmann “Centennials”. Was that A-Line/PPW? I remember it being a heck of an upgrade kit, with the price to go along with it.

Congrats! Way to turn a dog into something to be proud of…Ahhh I have a Nscale Gp 38…?Cox 47

From one tinkerer to another; really kewl Darth! [8D][tup] Where did you finally locate those worm housings? Did you order them from my LHS?

One thing I would caution about is using the stick-on weights to support the shell. I’ve had that tape let go over time, in spite of degreasing the mounting surfaces beforehand. If you want to stick with tape ([:-^]), Scotch makes a heavy duty indoor/outdoor mounting tape that’s more like the super strong servo tape I put in my RC car, but this can be found at Home Depot. I use it for motor mounting applications.

I second the motion for a video. [:)]

Thanks.[:D]

I got the worm housings from a brand-new condition (but pretty old) Athearn F7A I picked up at a train show for $12 last week.[:D] Everything in that F7 was in completely un-used condition when I got it, so I’d say I got a pretty good deal on that one. The worms weren’t even rounded off like in most of my other Athearns![:D]

I’ll be sure to keep an eye on the lead tape. I’ve found that if it let’s go, super glue does an excellent job of re-sticking it.[:D] So far, the only time it’s ever lost its stick is when I peeled it off of whatever it was stuck to (not an easy task!!).

I’ll see if I can figure out how to use the new digital video camera this afternoon. If I do, I’ll try posting a video for you all.[:D]

I haven’t heard of a DD40 repower kit, but I do know that sometime last year I think? A Line got Bachmann to make a run of undecorated Spectrum DD40s for them. I don’t know if they have any left at this point.

That is it then. It was an entire kit you could buy, and I think that it was well over $100.

Yes, CA does a great job of gluing the weights (and various body parts [:O]) to the frame or shell.

So what are you planning to do with all of this Union Pacific mega-power, Darth? [:-,]

Good question. A movie would be great!

Cheers to you, darth. i like the conversion. I think i’ll show this to my friend who has one of those Bachmann clunkers.

Just thought I’d let you all know I’ve got a short movie on my computer now, but it’s a 50MB mpeg for 1 1/2 minutes of video. I’ll try and find a way to size it down before I post it, since it even runs slow on my computer.

Just upload it to YouTube or Photobucket. They automatically compress it into Flash format.

That’s pretty cool![:D] Thanks for letting me know about that, or I probably NEVER would have uploaded it!

(edit) Oops, that didn’t work. Let’s see if this works:
http://s9.photobucket.com/albums/a70/DarthSantaFe/?action=view&current=BachmannDD40.flv

Cool video Darth! I’ve never seen one of those beasts run. I would expect it to pull about 100 cars.