Bolster Height of Micro-Trains Trucks?

Mr. Trainiac Nov 4, 2020

  1. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    I am an HO scaler, but I am making some N scale trains on Shapeways by request. I need to know the distance between the railhead and the top of the truck bolster so the car rides at the correct height. Do you guys recommend the pin-mount or screw mount trucks? What type of screws do N scale trucks use?
     
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  2. Inkaneer

    Inkaneer TrainBoard Member

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    Go to the MT website. They have that data there. I use screws to mount my trucks. Off hand, I don't recall what size.
     
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  3. Hardcoaler

    Hardcoaler TrainBoard Member

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    Just a note to say thank you for considering this element of product design.(y) Thinking of some past models by Bachmann and Life-Like that look like they're on stilts, it amazes me that some commercial manufacturers ignore this essential measurement.
     
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  4. Inkaneer

    Inkaneer TrainBoard Member

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    It's not that easy. You have to take into account the oversized wheel flanges to see if they will interfere with the car floor, coupler box or stirrup steps. And I am not just talking about the so called 'pizza cutters' either. Even the lowered .022" flange that is now standard is over 3 .5 times over scale. Some have gone to cutting holes in the floor of some cars to alleviate the ride height issue and allow free movement of the trucks/wheelsets. But lowering the ride height is only part of the situation. How about the coupler? If you body mount couplers then lowering the body also lowers the coupler. If you go with truck mounted couplers you have to deal with possible interference of the car floor with the coupler box/truck.
     
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  5. Hardcoaler

    Hardcoaler TrainBoard Member

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    It's a difficult balance to be sure. Some manufacturers like M-T usually get it right to my eyes.
     
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  6. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    The car I am designing is the Santa Fe 10-pack Fuel Foiler. It has open trucks that aren't obstructed by any car floor on top, so hopefully that mitigates the number of concessions I need to make. I hope that my model improves on the old Con-Cor one, because that thing rides way too high. What Micro-Trains page are you using? On the truck title image, it just shows this:
    Bolster height.JPG
    It shows the floor height is 7mm, but I need this:
    Bolster height_LI.jpg
    I need the height of the truck bolster, which is not on the picture. In a way, I need to know how far down the body bolster extends from that 7mm datum. I don't need coupler clearance since the cars are articulated: the intermediate trucks do not have couplers.
     
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  7. Inkaneer

    Inkaneer TrainBoard Member

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    Okay, I see. I don't think that measurement is available on their website. It may be that your best bet is to contact Micro Trains directly. Their phone number is 541 535 1755. Also there are upgraded trucks available from BLMA (now Atlas) which have a different height measurement. These trucks were designed to lower the car height without messing with the bolster. Unfortunately I don't have that measurement. I only point that out as a caution in case the owner wants to change trucks.
     
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  8. NtheBasement

    NtheBasement TrainBoard Member

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    Remembered your post when I saw the old gage block set my brother gave me last year. Hey, I actually have a way of measuring this! .205 on my Barber Roller Bearing short shank truck.
     
  9. PolishFinnish

    PolishFinnish TrainBoard Member

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    On my datasheet from N Scale Supply. I have the bolster height as

    Freight - 0.185" (4.7mm)
    Passenger - 0.240" (6.1mm)

    So far they appear accurate.

    [​IMG]
     
  10. tehachapifan

    tehachapifan TrainBoard Member

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    If memory serves, those fuel foiler cars (maybe it was just the impack cars) had bigger wheels at the ends than at the articulations. I want to say 33" and 28", but I don't have a solid reference to give. Don't take it as factual at my word, but it might be worth investigating.
     
  11. BigJake

    BigJake TrainBoard Member

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    Generally, the trucks at the articulations support halves of two adjacent units (one unit weight total) whereas the end trucks only support one half of one unit.

    So the wheels on the inner, articulation trucks would generally be larger diameter to support the additional weight, not smaller.

    I know this is the case on the Kato N scale Gunderson MAXI-IV 3 unit articulated double stack cars. End trucks have 33" wheels, inner trucks have 38" wheels.
     
  12. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    I have scans of the drawing that was published in Model Railroader a while back. (September 1982). Only one wheelset has a dimension (28" with 5' truck wheelbase) so I am assuming that goes for all the wheels. Generally that is drawing convention. I don't know how much ITEL changed the design from the original Fuel Foiler though. I think the Athearn model is mostly dimensionally accurate, but the detail is of course simplified.
     
  13. tehachapifan

    tehachapifan TrainBoard Member

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    But the impack and fuel foiler cars were originally designed to only carry a single 45' trailer per platform versus two 48-53' containers per platform as on an articulated well car. Not sure if the single 45' trailer per platform warrants a wheel larger than 28" or not.
     
  14. BigJake

    BigJake TrainBoard Member

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    Probably true, and for maintenance and other considerations, it may be preferable to have same size wheels on all trucks (end and interior).

    But it is unlikely that the end trucks, that carry less weight, would have larger wheels than the interior trucks, which carry more weight.
     
  15. tehachapifan

    tehachapifan TrainBoard Member

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    I'm just spit-balling, but perhaps with these cars it had more to do with ride height than weight (if they were indeed smaller intermediate wheels to begin with). Perhaps they wanted the lowest center of gravity possible and/or the lowest height possible for trailer loading/offloading. These were some of the first articulated spine cars, so they may have been somewhat concerned about how they would track, etc. (remember those early doublestack cars, with the bulky ends that reached the upper container?). The Impack end platform center sills have a sort of swayback shape to them, which kind of makes it seem like they wanted the trailer bogie platforms to be low. But, this is all a WAG and I don't know why I seem to recall something about this. Maybe the wheels were all the same size and all 33" or bigger.
     
    Last edited: Dec 24, 2020
  16. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    I think you are right on that. In addition to the small wheels, the wheel decks are about midway up the center spine. On newer cars, the wheel deck is level with the top of the spine. I'll have to look at my drawings and compare the ride height to one of my Athearn articulated spines, but the trailers probably sit about a good 8" lower than modern cars, if I were to estimate.

    Triple deck autoracks use 28" wheels, and they probably have about the same capacity as the double deck cars with 33" wheels.
     
  17. bill pearce

    bill pearce TrainBoard Member

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    Wow! I wrote an article for building this set, (For MR or maybe the AF society magazine). But as I'm in my 70's now I cant say anything factual but I can say that in any event, I modeled the car by eye so look up the article and see if there are different sized wheels for the ends.
    when I did any of the models I tried to duplicate the external appearance, not exact measurements.
     
  18. Thomas Davis

    Thomas Davis TrainBoard Member

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    I use either screws or pins as required by the model. If MTL trucks, then it is simpler to use their bolster pins.

    Edit: I missed the earlier post from the OP ID-ing the car being designed= so the questions originally in this space were already answered.
     
    Last edited: Dec 31, 2020

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