SW1200RS project stalled

I’ve experienced a roadblock to the progress of my SW1200RS project.  Recall that I broke one of the axle/gears while replacing the stock Proto 2000 plated wheels with nickel silver wheels from NWSL.  My friend Ted suggested that, since the Proto 2000 drive is a clone of a Kato, I should try using the gears out of a Kato switcher truck.  With no other viable option, I ordered the parts and crossed my fingers.  The good news is that Kato is prompt in delivering in-stock parts.


It didn’t take long to take one truck apart to pull out one of the axle/gears.  It was clear immediately that this wasn’t going to work.  The Kato axle/gear is about the size of an Athearn – in other words, too big for the Proto 2000 truck.  In the photo below, the Kato gear/axle is on the left with one wheel pulled off, the broken Proto 2000 is on the right.


It was a good try, but unfortunately it didn’t work out.  If anyone needs a pair of brand new Kato switcher trucks, get in touch with me 🙂

Back to my SW1200RS project… I might be out of affordable options.  The obvious solution is to purchase yet another Proto 2000 SW9/1200 so that I can cannibalize one of the axle/gears. That’s an expensive proposal, but I would have nearly an entire drive for spare parts.

Another option that comes to mind is to start over with an Athearn blue box SW7 drive for the unit with the broken gear.  I’m not sure how I feel about that approach because, from the outset, I wanted these two models to have the same drive.

Please contact me if you have a dead Proto 2000 SW9/1200.  I’ll buy it from you for parts.


15 thoughts on “SW1200RS project stalled

    • Good idea. The A Line/Proto Power West drives are built on the Athearn SW7 frame and trucks. Jurgen suggests, below, that this drive won’t fit. There was a series of comments on a previous post of mine where we went on at length about the Athearn drive. There was much discussion but no conclusions, so Jurgen’s observations notwithstanding, I’m still curious to see if it will work or not. It seems odd, but not impossible, that the Point 1 kit instructions indicate that the Athearn drive will fit if they didn’t try it to make sure.

  1. The Athearn drive won’t work. One of the reasons why the Athearn unit was so misshapen was because the existing drive components (which I think were first used in the S-12 model) would not fit in a scale SW switcher. The gear tower on the rear truck would not fit inside the cab, so they stretched the unit, moving the cab and rear pilot back about 1/8″, so the truck would clear. This also led to lengthening the hood, which then had to be made higher so that it wasn’t so obvious that it had been stretched. Typical bastardized Athearn.

    I wonder if other P2K gears are similar to the one in your switcher’s truck. Maybe there are other sources of those gears if other units had them. I can lend you the components from the drive I already modified so that you can keep your project moving forward. Mine is pretty stalled right now anyway.


    • Thanks Jurgen. I’ll take you up on that offer as temporary fix. CB’s idea (below) may be the permanent solution. I’m going to try to hunt down a donor drive because this might foreshadow future issues for my two units and any others that are eventually finished (I think Ted indicated he wants to finish his as well).

      Borrowed gears… thats funny.

      • OK, I had a feeling I might have something useful in my stockpile, so I went down to see what was there. Sure enough, I found a complete P2K switcher kit there. The only small issue is it’s a TH&B 55 model. Not that it was doing any good sitting anonymously in my cabinet downstairs (I have no clue how I came to own it…) In any case, it’s a better source for the gears than ripping apart the modified trucks on my 1200RS conversion. I will bring it out to the club next time.


    • This sounds promising, though I’m not entirely sure I understand. I picture the bushing as a tube that the split axles slide into and gear slides over. Is that the idea?

      At times like these it helps to be friends with a millwright. Solutions like this one seem to come as second nature for you.

  2. My knowledge of the Proto drive parts are limited to their earlier days when they were more closely patterned (copied?) from Athearn drives. That gear looks large enough that I’m curious if an Athearn gear salvaged from a blue box drive would work or for that matter might one from one of the old Ernst re-gear kits work?

    • Thanks for the suggestion Chris. We tried that and it didn’t work. I think the Kato gear is the same as the Athearn, which is the same as Proto 2000 drives from other locomotives. The drives under the Proto 2000 SW9/1200 appear to have a different and smaller gear from their road units. By smaller, I mean in diameter and tooth count.

      • Dear Hunter,
        I can confirm that Horizon part # ATH60024 Drive Axle Gear matches the original P2k GP18 mech, but does not match a first-batch P2k SW9 Part # 8049 (ATSF).
        I can also confirm that ATH60024 is a match for a current-batch Horizon (DCC ready, Mashima-can equipped) Athearn SW1500 mech…
        Happy Modelling,
        Prof Klyzlr

  3. Best just to find a cheap junker for sale on eBay, or someone who has parted a unit out and is selling drive components separately. The other option would have you modifying the Athearn frame quite a bit, and the P2K SW drive is quite smooth. IIRC, the new Walthers SW units have had totally redesigned gearboxes (along with most other components) so you’ll want an older LL P2K release.

    I believe the LL P2K SW8/900 and S1/S3 use the same truck, so gears from those may also work.

  4. Hello: Did you ever find a spare Proto sw1200? I am in need of a set of wheels for a Proto SW 12200 also so would gladly buy a spare set of wheels off you want to help defer the cost. I want to replace the wheel set with the rubber tires on my unit for better pickup.
    Don Janes, Sarnia

  5. Don, I ended up getting a spare gear from a member of the club.

    I replaced all of the wheels on two Proto drives that I built. I used NWSL nickel silver wheels. They are a direct replacement (which is how I broke the gear in the first place). So I have 16 spare Proto wheels. None of them has a rubber band on them. I didn’t know that Proto used wheels with rubber band treads. Anyway, you’re welcome to those if we can figure out a way to get them to you. Contact me offline if you want to figure something out.


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