Resin Printing Burlington Northern Trough Train

Mr. Trainiac Aug 3, 2020

  1. 7dmack

    7dmack TrainBoard Member

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    I recently saw a video on YouTube from May last year at the Oklahoma Mode Railroad Museum of 3 Trough Train cars on a HO layout. All but the last few sections of the last car were painted and decalled.

    This is a project I've always thought would be neat to see realized. I have made some drawings and drew an end and middle unit in 3D. I'd printed a couple parts and built a mockup of a center unit, then the disease happened. Since then, my 3D drafting skills have improved and if I were to continue, I think I would start over. Operating doors is a must for me since I use live loads. It won't work in the rotary dumper though. I've tried to think of a way to use the hot shoes to open and close the doors on the model but haven't come up with anything yet.
     
  2. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    That video on Youtube is my Trough Train printed from Shapeways. What he did was buy one of each type of unit, and then cast the remaining intermediate units in resin. I thought that was a smart idea to save money. As long as you're not reselling them, it's not copyright infringement. The decals that person used are available from Circus City Decals. Someone I worked with on Shapeways to develop the Trough Train provided Circus City with enough photos to create the decal sheet. I'll use it if I get this model done.

    Do you have any good photos of the car? What resources were you using to design your model? I was just looking at the door release shoes today, but I realized that I don't know what the internals of that mechanism look like. All I can see is outer surface of the shoe. On the original model, I basically just slapped it on the side sill, but there's nothing behind it. On the new one, it would be cool to at least represent the mechanism with some basic shapes. Are they mechanically interlocked with the doors, or is it simply a button for a pneumatic system?
     
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  3. 7dmack

    7dmack TrainBoard Member

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    There was a series of photos of the infamous accident that ended the Trough Train service in March 2002. It had several photos of the separated car and joint that failed. I think it was on a DRGW site, maybe Nathan ???, posted photos of the cars post wreck and there was one shot that showed the shoe is basically a switch. It is a plate on a hinge with a small air line behind it. This is the only photo of the wreck I can find now and it is not that helpful: https://archives.dcl.org/digital/collection/photos/id/302/

    I also have some photos that will hopefully someday be in a book about the BN that the author shared with me but are basically just side views of individual units. As far as figuring dimensions, I started with part of an arrangement drawing I found online and then made a spread sheet and put in numbers until they added up to the 275' 8.75" (over strikers) but were reasonable, ie not random fractions of feet. IIRC, the end units were 20' 2". Other dimensions and rivet spacing were scaled off of photos. It has been awhile since I worked on the project and most of the info is on another computer.
     
  4. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    I think your description of the hot shoe is correct. I found a few patent descriptions of how it works, and other Johnstown cars like the Autoflood use them too. The Rapido and Exactrail models represent the shoe, but I wasn't sure how accurate they were, especially in terms of mechanism behind the side sill.

    I had also seen some of the wreck photos, there were a few posts on an O scale forum that had some good detail photos. Those were especially helpful in figuring out what the ends of the intermediate units look like.

    The biggest piece of guesswork on the model has been the outlet doors. They always seem to be in poor lighting, and them being painted black doesn't help either. I'm confident that they are more accurate than the first version, but there are still probably inaccuracies in my design.

    My mechanism for opening the doors consists of clips on the ends of the doors to hold them shut. I'm thinking about using some kind of ramp-like system on the tracks to close the doors one they are open, similar to those car re-railer tools. As the train rolls though the unloader, the ramp system pushes the doors back up until they clip shut. Opening the doors could be a similar system, where they hit something in the gauge that opens them; maybe I'll experiment with some kind of tab or wedge on the bottom edge of the door.
     
  5. 7dmack

    7dmack TrainBoard Member

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    That door latch system is more practical than what I was thinking. I was wondering if electricity applied to the hot shoes could bend Nitinol wire latches and allow the doors to open. I use dyed walnut shells for coal. It works well in the loadout and dumper but sometimes static electricity makes it do strange things. Another issue I found, is the black dye makes some of them stick to magnets. I found that out when I magnetized the doors on my mockup.

    In one of the wreck photos, there is a cable attached to the door. I can't tell if it is a limiting strap or used to pull the doors closed. I remember a post on Trainorders talking about needing to check all the doors when the train arrived for loading. The poster said they used a bottle jack to close them if open.

    Thanks for the link to the Circus City decals.
     
  6. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    The Trough Train project is back in action.

    Another modeler was able to share with me some of his photos of the car, which are a big help for stuff that was previously unknown to me or simply guessed at.

    Here is a look at the newest version of the car. You can see outlet gates that are finally accurate, and newly added jacking pads, which are those flat plates on the corners. They are a bit difficult to see, but I noticed them in a few photos I found online, so I added them in. The door release shoe is new as well. I found the patent online, which had some good diagrams on how it works. It's not exactly the same model as the one used on the Trough Train, so I changed it a little to match my photographs.
    Corner Underside Detail.JPG

    I also changed some rivets into bolts. You can see them on the ends of the cars, and I also added bolt heads in a few other places as well. They look pretty nice on the CAD model, let's just hope they print.

    Next up will be the brake equipment. This will be pretty difficult, as not much is visible. I can see the brake wheels and retainer valves, but the resevoir and triple value are hidden. I suspect they are mounted to the center sill between the outlet chutes, or they are up underneath the slope sheets. There is a lot of space up in there, it's basically a void above the trucks, you can see it a bit in the photo below.

    The below photo is not up to date, I accidentally deleted the rivets along the center panel joint, so I had to go add those back in, but it's a good overall view.
    intermediate unit new gates.JPG
     
  7. SLSF Freak

    SLSF Freak Staff Member TrainBoard Supporter

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    Holy cow, nice! I'd love to see this printed on a resin printer and primered up to show off those details. (y)

    Mike
     
  8. HemiAdda2d

    HemiAdda2d Staff Member TrainBoard Supporter

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    Very promising! I had long wanted one of these, but since changing modeling focus, a mere interest rather than a must-have... I doubt the prototype would agree with the 16° curves in Byers Canyon, and thus restricted from the Moffat...
     
  9. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    My drawings say a minimum radius while loaded of 31.4 degrees, which isn't half bad. I have read that the original specification was for a 20 degree curve.

    How well the train navigates those curves is debatable. The car was known for having issues at the articulation joint, and having coal get stuck in the sliding plates. I doubt that force is enough to derail the car, but all that coal having to get compressed and shifted on the inside of a curve probably wasn't too nice on the track. I can imagine having a lot of lateral loading on the wheelsets.
     
  10. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    Here is another progress update:

    The end unit is coming along nicely. I thought I should work on those, now that the intermediate units are at a state of near-completion. It will be nice to see a full train, and then I can go back and fix any mistakes or add small details I forgot. The intermediate units have pretty much all their major work done; if I worked on those any longer, it would basically be nitpicking and adding extraneous stuff that probably won't matter or even show up in the print. Speaking of printing, I haven't even printed any prototypes yet. I expect to make more changes to improve the printing, so I can't make too many more model changes that I'll have to undo anyways.
    Tough Train End Unit.JPG

    A lot of the major dimensions are the same as the intermediate units, so the end came together quickly. I was basically just duplicating rivet spacing and panel dimensions; most of the heavy lifting and guesswork was finished on the intermediate unit. The end sill is slowly coming together; that's really what separates this unit from the others. The image lacks a coupler box, that's what I have been working on today.

    I am also rethinking the outlet gate mechanism. Now that I have the hot shoe figured out, I was considering making a functional system using it. Like the real one, it would contact a wayside detector. I was thinking about using a thin metal foil on the outside, which would allow me to solder a wire to the backside. When it contacts the detector, it completes a circuit to power a servo that rotates the latches to open the gate. It sounds very complicated, so I may have to make some prototypes and experiment. I have room to hide a servo under the slope sheets or between the outlet gates.

    A magnet-based system is another alternative, and may be more practical. Like the clip system I described in an earlier post, the gates could be opened by contact from a device in the gauge. I would just need magnets strong enough to hold back the coal load, while still able to be pulled apart by relatively light contact forces.
     
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  11. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    A monumental occasion: the first experimental print is finished.

    It turned out better than I had hoped. It took about 6 hours, so I ran it while I was at work. I expected to come home to a failed blob, but it actually looks really nice. The quality and consistency of the Photon printer always surprises me.[​IMG]

    I’ll try to take some better photos after it cures under UV light and after I remove the supports. The articulation joint and door hinges came out well, those were the tricky geometries, as well as the wall thickness of the side sheets. I will have to see how flexible they are after removing the supports behind them, but they don’t feel too bad right now. I expected the side panels to be thin and flimsy, but they don’t yield very much to my fingers when I pick it up.

    Next up will be another test car with some changes made to the details and support structure. I might try to crank out a quick print of the smaller detail parts too.
     
  12. SLSF Freak

    SLSF Freak Staff Member TrainBoard Supporter

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    Nice!!! On print times, one thing I do for my drafts is I use a .075 layer height. Once you get the exposure time dialed in (it shouldn't be much more than .050 layer height) then your draft print times will come down. I've even found that .075 isn't even half bad, resolution wise. (y)

    Mike
     
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  13. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    It's been a while since I updated, I've been doing some printing and created a few more prototype intermediate units while I was working on the end units. I also picked up the Anycubic Wash and Cure 2.0 machine, and the most recent test print cleaned up pretty well in the machine. If I am to be printing at least 13 units for a full train car, I figured the washing machine would be a lot better than washing parts manually and putting them in a homemade UV light enclosure.

    I've been working on smaller aspects of the model now, getting more into fixing printing issues, so there isn't much to show in terms of new CAD on the car itself.

    I have been working on trucks though. I cranked these out last night using drawings and prototype photos for the bolster and spring package detail.
    ASF Truck model.JPG

    These will utilize Tangent axles with spinning bearings like the Buckeye trucks did. There are still a few more things I need to add, such as casting and foundry marks, as well as the side bearings on top of the bolster. Since this is an articulated truck, it needs two sets.

    Initially, I was considering buying Tangent trucks entirely, but outfitting an entire Trough Train car with them gets expensive quick. Technically the Trough Train uses ASF Ride Control trucks, but the Tangent Barber trucks look very similar. Adding the correct side bearing arrangement is a good justification to avoid Tangent sideframes.

    Next up will be the National Unitruck III. I want to use Tangent roller bearing wheelsets on it too, I might have to get creative on the mounting and assembly of that truck.
     
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  14. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    More trucks: ASF Truck model.JPG

    Compare this with the photo in the previous post to see the differences. I added the casting marks and serial number to the sideframes, as well as the lightening holes along the top. There are also a few details added around the lower spring platform.

    I only have one close-up shot of the trucks to make out the serial number, that is the long string on the right side of the truck. It would be cool to make unique serial numbers for each truck, but I can't make them out in other photos, and that may be going a bit overboard.

    Another addition were the side bearings on the bolster. Spine cars use the same roller system, although most well cars have a different design that uses a platform with the bearings cantilevered off either side of the bolster.

    An interesting note is the truck casting date of 9/1994 (on the left side). I know I'm supposed to be our resident Trough Train expert, but I don't remember if the build date was 94 or 95. The number between ASF and 9 94 is probably a heat code for the batch that it was poured from in the foundry. The octagon with an A inside of it is most likely a designator for the foundry itself, in this case most likely the Alliance, Ohio facility.
     
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  15. Ike the BN Freak

    Ike the BN Freak TrainBoard Member

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    Is the truck different than what is commercially available, or just while 3Ding, just adding to it?
     
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  16. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    The Trough Train rides on ASF Super Service Ride Control trucks. I want to use the spinning bearing cap feature that has appeared on some newer models in the last few years, and it actually makes printing and designing the trucks easier, since I no longer need to assemble the trucks around the wheelsets. Unlike styrene, you will most likely break the 3D resin when trying to insert the wheelsets into the trucks. The spinning bearing is a snap-in design, so there is no bending to fit a needlepoint bearing into a cup.

    The closest commercial model is the Scaletrains ASF truck, but this has been unavailable for a while now. I remember seeing them in hobby shops a year or two ago, but apparently they haven't been rerun as separate parts lately.

    The Tangent trucks that use the spinning roller bearing cap are a Barber S-2 design, but cast by ASF. There are some differences around the journal, and the ribs that support the spring platform are different as well. I could use these trucks as a reasonable stand-in, but it would be more expensive than just buying Tangent wheelsets and printing my own sideframes.

    Athearn Genesis has a roller bearing truck too, but they use plastic axles, and overall the truck isn't as high quality as the others.

    The Trough Train truck also has two sets of side bearings since it is used on an articulated car. Using a normal off-the-shelf truck wouldn't get me that feature. Granted, you don't really see the bearings when the car is in operation, but I think I should include this detail if I know it is there.
     
  17. Ike the BN Freak

    Ike the BN Freak TrainBoard Member

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    Maybe someday this will get scaled down to N, not that I need another project. But not sure if any truck exist in the N world that would work. Were these 100T or 125T trucks at the articulated joints?
     
  18. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    These were 100 ton trucks with 36" wheels. In N scale, you probably can't tell the difference between an ASF or Barber truck, so any 'modern' truck would probably work.
     
  19. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    I got my shipment of parts from Tangent the other day, so I have been prototyping the ASF trucks. This is probably the third version I have printed. I keep going back and changing one or two things until they look and operate perfectly.

    The biggest functional change was a redesign of the Tangent axle carrier. The first version of the truck carried the design over directly from the Buckeye truck I made before, but in the process of assembling and working on the truck, I realized how fragile it was. Removing and reassembling the axle had a tendency to snap the 'C' shaped clip open, so the wheelset would simply fall out. I don't expect to disassemble the trucks many times, but for testing and painting, it needs to survive at least a few wheelset removals.

    Here are some close-up photos of the truck assembled, but without cleanup. I removed the supports, but you can see some surfaces along the top that still need to be sanded. I also added brake beams. These are printed in two halves for ease of support removal. You can see the seam under the bolster where the two halves meet.

    I shot these on my iPhone, which doesn't have optical zoom, but I think you get the idea.
    [​IMG]
    [​IMG]
     
  20. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    Now that the intermediate trucks are printing, I figured I would work on the end trucks. It's hard to say what the strangest feature of this car is, but the National Unitrucks are arguably the most unexpected. Pedestal trucks belong under a Bobber caboose, but there have been a few attempts to bring them into the modern era, the Front Runner being the most well-known. The Trough Train used Unitruck III, which is basically a 36" version of the 28" Unitruck II under the Front Runner.

    This version of the Unitruck is better by a mile compared to my first version. Go back to the first page of this thread if you want to see renders of that model. I made this into a multi-piece assembly in order to get the Tangent axle into the truck. The bottom section and the springs fit into the top section, that way I can add the Tangent axle and then drop the assembly into the upper section which is secured to the car body. There will be multiple trials of this model; I still need to figure out how to best assemble and align all the parts of this truck so it works properly.
    Unitruck.JPG
     
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