SP H-12-44 Project

jwaldo Nov 11, 2022

  1. jwaldo

    jwaldo TrainBoard Member

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    For my next project, I’ve picked up a Minitrix H-12-44. There’s just something charismatic about F-M’s opposed-piston, toaster shaped switchers. Southern Pacific had quite a few H-12-44s, and whoever designed the Minitrix model might’ve been a secret SP fan (or just used a lot of SP reference photos), because both ends already have cutouts for the appropriate SP light package. Somewhere under the very unprototypical paint job lurks a very nice model.



    I started by testing the locomotive on the local club layout. At first it stuttered and stalled every few inches on the less-than-spotless track, but once I cleaned the wheels it purred along, even on notoriously buzzy DCC 00 mode. The whole time I checked the motor carefully for overheating. Turns out I should’ve checked the headlight instead. Under the constant high voltage of the DCC system, the headlight bulb got hot enough to start warping the cab roof and horn. Fortunately keeping the kludgy stock horn isn’t in my plans, the little dent in the roof will be an easy repair, and I intend to upgrade the lighting to LEDs.

    [​IMG]



    With the locomotive’s reliability proven, it’s time to start making upgrades. I began by removing all of the add-on parts from the shell and soaking the shell in my go-to paint remover, 91% rubbing alcohol. Turns out the lightbulb was more effective at affecting the paint. Whatever they painted this thing with is tough as nails! I’m hesitant to throw any harsher solvents at it, having heard plenty of horror stories about paint stripping going wrong and damaging plastic, especially on older locos.

    [​IMG]

    So for now it's nothing but soak, scrub, repeat for the foreseeable future.
     
  2. alister

    alister TrainBoard Member

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    Do you realise that the Minitrix shell isn't very accurate? A better solution is to use a Atlas VO1000 mechanism under a shapeways FM H12-44 shell. You then have the beginnings of an accurate model. But you may be able to add louvres in the correct locations and make a suitable representation. I have a few of these myself as well as the shapeways shell. Just my opinion. :)
     
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  3. SP-Wolf

    SP-Wolf TrainBoard Supporter

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    It's "fairly" accurate for a late model H12-44. SP class DS-121. Short framed unit. Minitrix even put the holes for SP's light package on the shell. The VO-1000 mechanism is to long for this model H12-44. It is however suitable to the older "narrow" framed H12-44's. As they also had a longer frame.

    Here's some old crappy photos of what I did with one of mine
    I added some details and I used a Bachmann NW-2 mechanism. Changed Bachmanns decoder to a Digitrax.

    [​IMG]
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    @jwaldo -- looking forward to seeing what you do with this venerable 'ol locomotive. Your 70 tonner is outstanding.

    Best regards,
    Wolf
     
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  4. jwaldo

    jwaldo TrainBoard Member

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    The Minitrix is actually fairly accurate for SP's late-production H-12-44s, which did have the short thick frames and different louver arrangements from most H-12-44s. It's inaccurate for most H12s, but right for what I want to recreate. Plus it saves me from having to track down a VO1000, which seem to have become rare and pricey.

    That looks awesome! The NW2 chassis looks like it might even leave enough room for a sound decoder. I've been keeping an eye out for an NW2, but they're even rarer than VO1000s. For now I'll have to stick with the original for now.
     
  5. alister

    alister TrainBoard Member

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    Well now I know what to do with some of my spare shells - make them SP. Oops what am I saying :LOL:
    I'm supposed to be a Santa Fe modeller!
     
  6. SP-Wolf

    SP-Wolf TrainBoard Supporter

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    Well - AT&SF also had this model of H12-44. Within the 503 class. I believe starting with # 550 through 564. (And - possibly only road numbers 559 through 564) - My reference book (Iron Horses of the Santa Fe Trail) is not clear. These machines were the short frame variant. Pretty much like the Minitrix model. Just remove the extra holes on the front and rear (Above the head light and next to the rear light)

    AT&SF road numbers 550 through 558 were delivered in March and April of 1956
    And road numbers 559 through 564 were delivered in March and April of 1957

    May be of interest: # 560 is being restored by Southern California Railway Museum. (The ex Orange Empire Railroad Museum)

    Best regards,
    Wolf
     
  7. brokemoto

    brokemoto TrainBoard Member

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    When I rode the SP to school in California in the late 1960s, I saw these things everywhere on the SF Peninsula. There was a yard at College Park, another yard at Santa Clara and the station at Cahill Street in San Jose. Most of them were in the switcher version of the "bloody nose" scheme at that point, but there were one or two still in older schemes.

    I do not know how well that mechanism performs on DCC. It does not run well at switcher speeds on DC. It runs tolerably at scale speeds above thirty five MPH.

    If the ninety one per-cent did not strip it the first or second time, it was rare that it would do any more. Sometimes you simply must go to a hobby store and buy some purpose made paint stripper. Brake fluid, if used cautiously, will get off the paint. In some cases, brake fluid will ruin the shell. In some cases, it will make it brittle. Some shells will stand up to it. If you scrub it onto the shell with a toothbrush, then wash promptly with soap and water then rinse immediately, sometimes you can get away with it. Use rubber gloves and wash your hands fifty times after you are finished. Brake fluid is really toxic.

    I have pretty much stopped using it. I have ruined only one or two shells, but the number that I have made brittle is high. The last is what made me give up using it.
     
  8. jwaldo

    jwaldo TrainBoard Member

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    Alcohol and elbow grease got 80% of the paint off. Carefully-applied Q-tips with lacquer thinner got off another 15%. The last 5% is a thin residue that seems almost impregnated into the plastic; not even sanding took it off. The old shell is a little bit brittle; one of the window frames broke in the stripping process, but I plan to re-work the windows with new glass anyway.


    Speaking of windows, the molded-on sunshades had to go. I filed them off along with the cab armrest and the slight overhangs on the roof. Solvent putty and styrene were liberally applied to various gaps, dents, and molding marks in the shell. Now I just have to wait for everything to dry before I can smooth it all out.

    [​IMG]
     
  9. BigJake

    BigJake TrainBoard Member

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    The history of FM's two stroke, opposed piston diesel engines is long and fascinating. In addition to locomotive applications, they powered submarines and ships in military and commercial applications. They still (as of 2021) manufacture engines for stationary applications (generators and pumps).

    They had cooling problems in MU locomotive applications, but their original applications were in submarine and surface ships, where cool intake air was plentiful. Interestingly, their first foray into RR locomotives was delayed by the Defense Production board, which wanted their efforts dedicated to supplying naval applications in WWII.
     
  10. jwaldo

    jwaldo TrainBoard Member

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    And the sound they make! Don't forget the sound!

    While the filler cures, I started measuring out where the nose grab irons should go. Nothing quite lined up. Turns out, everything on the nose is ~18" lower down than it should be. Lights, sand hatches, access doors, all of it. Looks like I have even more filling to do today.

    [​IMG]
     
  11. BigJake

    BigJake TrainBoard Member

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    Looks like the uppermost accoutrements would be too high (into the rounded corner between front and top of the hood) if moved up that far (?), or should the whole hood be raised?

    A look at photos on google revealed a variety of locations on the prototypes, suggesting they were customized per customer (as was common). And the model maker likely chose the first or most popular prototype/road for their placement on a common mold to cut costs.

    I admire your skill and attention to detail!
     
  12. jwaldo

    jwaldo TrainBoard Member

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    The hood height seems right, SP's thick-frame H-12-44s just really did have their signal lights mounted that high up, with metal brackets going around the curved edge. I'm guessing Minitrix didn't want to attempt that complexity with 70s molding technology, so they moved everything down to an easier-to-tool location.
     
  13. tehachapifan

    tehachapifan TrainBoard Member

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    I started an SP H-12-44 a while back but haven't ever finished it. This thread has re-sparked some interest in working on it more! Before I stopped, I did do several mods to raise all the low appliances and such on the front, as can be seen below....

    [​IMG]
     
  14. BoxcabE50

    BoxcabE50 HOn30 & N Scales Staff Member TrainBoard Supporter

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    "...toaster shaped..."

    I love it! That fits, so perfectly! (y)(y)(y) :D
     
  15. alister

    alister TrainBoard Member

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    I have a Shapeways shell which I got after I started modifying the Minitrix shell. I don't want to take away from @iwaldo 's thread. Might post my Santa Fe roster in a separate thread. Russ, fancy doing that to a fine Santa Fe model!! :LOL:
     
  16. jwaldo

    jwaldo TrainBoard Member

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    That looks great! If you don't mind my asking, how did you do the pilot steps? Those metal parts look a lot sturdier than what I was planning.
     
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  17. Calzephyr

    Calzephyr TrainBoard Supporter

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    Is that a Bachmann NW2 chassis?
    I would just leave it as DCC only.
    That looks fantastic as is.
     
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  18. jwaldo

    jwaldo TrainBoard Member

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    Consensus seems to be that the Bachmann NW2 is the one that fits with little/no modification. I've never seen anyone do it with the BLI or Kato chassis.

    I got all of the parts for the sand hatches on the nose, now I just need to let the glue cure before I clean up any excess styrene. I also thought I'd make some coupler mounts for the pilots, but it seems the one tool that didn't make the move to SC with me is my 00-90 drill and tap set. Without that, I'm at an impasse. So instead I opened up the exhaust stack holes and made some new stacks out of brass tubing with the walls thinned down.

    [​IMG]
     
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  19. tehachapifan

    tehachapifan TrainBoard Member

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    Thanks! The pilot opening was filled with styrene sheet and the steps are made from styrene strips. Unfortunately, I can't recall what size I used now. I sanded a bevel/angle into top of the middle strip in the steps. For the metal L brackets, I cut some framing off of an etched metal detail part set and bent to shape. Nothing too fancy, but it works pretty well!
     
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  20. alister

    alister TrainBoard Member

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    Alternative way to do the pilots is to use 2 Atlas N Scale FM H16-44 walkways, cut the pilot and steps as one unit from the Atlas model (narrow end only) Cut off both front and rear pilots and steps as one unit each from the Minitrix shell. Glue (CA) the Atlas pilots / steps onto the Minitrix unit. I can provide a picture if you want. Unfortunately Atlas doesn't seem to have many parts in stock these days.
     

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