Resin Printing Burlington Northern Trough Train

Mr. Trainiac Aug 3, 2020

  1. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    After a long development stage, the first production Trough Train bodyshell rolls off the line on July 20, 2022

    [​IMG]

    I had major problems developing the articulation joint and door locking system. I printed 8 or 9 prototype cars, each with slightly different changes, testing door clearances, truck screw hole sizes, articulation and other aspects of the car. For the doors, I settled on magnets. This was a major aspect of my preproduction printing. I needed to test different arrangements and angles for the magnets, and printing new car bodies was the easiest way to do it. I wanted them to be strong enough to support a coal load, while still being easy enough to open for unloading. It was the least mechanically-intensive design and seemed the most practical. There is a magnet on the bottom corners of the doors, and magnets embedded in the body of the car. They attract each other to snap shut. I plan on having wayside magnets at the unloading site which pull the doors open as the train rolls past.

    The articulation joint reverts back to a similar design theory used on the Trough Train 1.0. Initially, I had an elaborate floating baffle system with springs that worked similar to Talgo or Turbotrain monoaxle trucks. It was too much of a hassle to assemble the car, so the final design is greatly simplified. It will improve reliability and make storage and disassembly of the train practical. I pack up my trains often, so I needed an easy way to take the cars apart to put in a box.

    The model shown above has the supports sanded down, but there are some other details I still need to add, like internal bracing and jacking pads. The doors will be installed after painting, which I am doubtful I will finish by the end of the summer.
     
    Last edited: Jul 21, 2022
  2. gjslsffan

    gjslsffan Staff Member

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    Man that thing is so stinking cool! Those trucks sure look good too. It will sure be something when you get it all done.
     
  3. HemiAdda2d

    HemiAdda2d Staff Member TrainBoard Supporter

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    Impressive! Operating doors? Wow, that's a whole degree of difficulty above crazy! Kudos!
     
  4. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    Quick update

    Here's a photo of the A-unit. The lighting's not the best; I get better photos when the sun is out. It's a little washed out and hard to see the details. The end of the car is pretty cool with all the rivets and grab iron bolts. The Unitruck has a Hyatt bearing on the unit I'm modeling, while the standard trucks are using Tangent Brenco bearings. I'm not sure if all units had Hyatts on the Unitrucks, but I thought that was a cool detail that adds a bit of unique flair to the end of the car. I have chosen to model BN 552006, the unit involved in the wreck that brought about the withdrawal of the cars from service. I have some good close-up photos of that car. If I make a second one, I will model the class leader 552000, which has the logos for different companies involved on the side.[​IMG]

    I need to make a few changes to the coupler box, but this is what the car will look like. I assembled the Unitrucks and temporarily set some doors on the outlet gates for the photo. With the A-end, I have the last articulated truck, meaning I can roll the model around without leaving one end unsupported. I still need to print the B-unit, but seeing the car snake through curves is really mesmerizing. It looks almost fluid with the short units, especially on wider radius curves.
     
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  5. alister

    alister TrainBoard Member

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    Some how I missed this! Any chance you might scale this down to N Scale?
     
  6. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    I'm reluctant to. There are a number of changes that would need to be made. The truck mounting would be different, which means the articulation joint needs to be redesigned too. The coupler box would have to change, and the design of the Unitruck would have to change in order to accept an N scale axle. There is a lot of testing involved to make sure everything assembles and operates properly, and I don't really want to stock up on N scale trucks and couplers that I'll never use.

    The wall thicknesses would probably be too thin in N scale, so I can't just scale down the existing HO model. I would have to redesign the entire model and update a lot of dimensions to make sure the model prints and operates successfully. I've done that once or twice for my Shapeways store, where the N and HO versions are completely separate models, and it's a lot of work for a model that would only generate one or two sales.

    I've had people ask me to design an N scale model from the beginning, and those usually work out, but modifying a design intended for a different scale ends up becoming its own project.
     
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  7. Ike the BN Freak

    Ike the BN Freak TrainBoard Member

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    Hypothetically, what all trucks/couplers etc would you need? I keep watching this and think if I were to do it, I'd want 5-6 cars.
     
  8. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    I'm not sure about couplers; I have a general idea on how the Micro Trains couplers work, but I have never looked at them up close. If I were to do an N scale trough train, I don't know if I would print the coupler box as part of the model, or if I would simply attach a box. There isn't a lot of room to thread a screw hole, and the box definitely has to be body-mounted, so maybe I would print one.

    What's a popular aftermarket truck in N scale? In HO, most people going for high-end builds are using Tangent; are most people using Micro-Trains in N? They seem to be the most readily-available at hobby shops. I doubt you could tell the difference between a Barber or ASF truck in N, so their regular 100 ton roller bearing truck would probably work.
     
    Last edited: Dec 14, 2022
  9. alister

    alister TrainBoard Member

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    No worries, just had to ask! :)
     
  10. Ike the BN Freak

    Ike the BN Freak TrainBoard Member

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    I'd agree with the printing the box, just for the extra "strength." As for the style, the 1015 is the most common/popular, as it is also the same basic specs as the accumate or mchenry, and a few others now.

    As for the truck, the issue with many of the Micro-Trains trucks is they have an offset bolster. The 100T one does not. Depending how the car body height, the BLMA/Atlas truck will allow it to sit a bit lower than the MTL one, and both of those trucks use .540" axles, which seems most common for N.
     
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  11. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    Here's a few more progress photos. I have all the bodyshells printed, so I'm moving on to some more details. Today I was working on the internal braces that go between the side panels. This is a difficult part to print, so I decided to mix styrene and printed parts. I printed some corner gussets, but built the rest from styrene strip. Two round rods form the main spacers, and strips fit into slots on the gussets to form the x-brace in the middle.

    I have six done tonight, I need to print the second batch of gussets to finish the rest. After that will be the jacking pads. Those are basically just flat plates on the bottom corner of each unit. I left them off the body print since they would be difficult to support, and the sanding and cleanup would basically ruin them. I thought a styrene part would look a bit crisper over a half-sanded blob.
    [​IMG]
    [​IMG]
     
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  12. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    Like Thanos, the Trough Train is inevitable.

    I'm hitting the painting stage right now, at least for the bodyshells. The model is getting Alclad metalizer paint. I started with Tamiya Grey primer in the spray can, then put Alclad Black Gloss over it. I realized the Alclad makes the Tamiya paint soften, so primer is mostly useless. Alclad Black directly on the 3D printed resin works fine.

    I put a layer of black down, sanded it with some foam sanding pads to flatten some printing lines, and put another coat on. This photo is from the first coat going on. It's not much of an art piece, but it shows there's still progress on this project.

    I am re-printing all the trucks, and already made a 2.0 version of the outlet gate doors. There was a print-orientation issue with the doors that caused the corners to warp when the build plate lifts in the printer, so I changed the support angle to fix it. The trucks have a design flaw to fix: the journal for the Tangent rotating bearing cap axles cracks when you take the wheelsets out for painting.

    The plan is to test one truck of the new version. If the wheelset assembles, paint the rest before putting wheelsets in, pray it works, and never disassemble them again.
    [​IMG]
     
  13. HemiAdda2d

    HemiAdda2d Staff Member TrainBoard Supporter

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    Incredible work!
     
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  14. Kurt Moose

    Kurt Moose TrainBoard Member

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    Starting to take shape, keep us updated!(y)
     
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  15. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    Parts are starting to come back from the paint shop. The outlet gates are finished. The exterior is flat black, while the interior is Alclad aluminum. I wasn't really sure where the delineation between exterior and interior paint started on the prototype, so I masked the door so the black wrapped slightly into the inside. I didn't want any aluminum showing on the outside of the car, and when the door overlaps with the chute walls, you can't see the black lip on the inside anyways.
    [​IMG]

    Here's one of the intermediate units in Alclad aluminum as well. I have been painting all of them aluminum, and then the next step is to paint the underside and ends flat black to match the doors. I might start on that tomorrow night. You can also see the brake equipment underneath the car. With a 13 unit car, there are 12 articulated trucks. Each unit brakes the two adjacent trucks, so every other intermediate unit has a brake piston. The reservoir and control valve populate the remaining units that lack the piston and lever components. As far as I can tell, the Unitrucks on the end are unbraked. Aclad is difficult to photograph. In this picture, it looks like regular aluminum paint like you could spray with acrylic, but in other angles, it reflects light like real metal. Looking at a blinding white rectangle isn't a good photo, so this angle is better to show off the details. Some cars look nicer than others; this is one of the better ones. The difficulty with Alclad is that it really highlights any printing and painting defects. Some cars have layer line errors or dead pixels in the printer that give a vertical or horizontal streak down the side. It's not too bad with acrylic paint, but thin reflective lacquer shows it off well.
    [​IMG]

    Just for fun, here's another look at the Unitruck. The two end units are still unfinished, I've just been building the intermediate units for now. I need to reprint them to fix some errors and add some additional details that I forgot about. This one got as far as the Alclad base coat before I noticed. There are some dimensional errors in the articulation joint that affect coupling, and I need to add some more details on the end to support the ladders and crossover platform. Now it will become a testbed for truck and coupler box improvements.

    The inner support beam and Unitruck casting itself get installed after Alclad to make masking and painting easier, which is why they are raw 3D resin and the rest of the car is black (which is starting to wear off by handling it too much).

    [​IMG]
     
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  16. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    Got the green panels painted on a few of the sections. The three leftmost units on each car are painted green for the Trough Train logo. The end units are printing now, but I thought I'd get a head start on painting these ones so I could start sealing in the decals with clear coat. I'm excited for these four because I get to use the cool decals rather than boring warning labels like the middle units have.[​IMG]
     
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  17. Kurt Moose

    Kurt Moose TrainBoard Member

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    And here comes the Cascade Green!:D
     
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  18. HemiAdda2d

    HemiAdda2d Staff Member TrainBoard Supporter

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    Exciting updates! Thanks for keeping us drooling!
     
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  19. Mr. Trainiac

    Mr. Trainiac TrainBoard Member

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    I haven't updated this one in a few weeks, but the Trough Train is now complete. I got it finished the last week of July, so I've had time to run it in. I like most of the model; there are a few things I still need to fix though. It's mostly minor stuff like how the brake details are attached, and I need to add another layer of clear coat. The aluminum Alclad is still pretty fragile.

    I also need to design a proper storage box with foam. Bubble wrap will not cut it in the long term, especially with the brake details and other smaller parts on the underside of the car. I am planning on building a second Trough Train next summer, so this first model will get paint touchups and reworks when the second one comes to the same point.

    Here's the completed model on the club Free-Mo modules outdoors. The Alclad looks good in the sun, but the BN Cascade Green is way too dark. I will probably repaint the end units along with the other changes.
    [​IMG]
    [​IMG]

    Overall., I am pretty happy with the results. This was a monumental project, and there's a sense of relief now that it's finished. A full train of these would look awesome, and now that the bugs have been worked out and the 3D models have been designed, making a car takes only 2 or three weeks if I really try.

    It has been a great experience, and really shown me the limitations and potentials of 3D printing. I'm not sure how to end this thread, but I feel a bit empty as well as proud. This model has been my charge for two years, and with it being finished, it feels strange not having any other tasks in my mind related to this project. It rose from the resin vat like Venus from the seafoam, and changed my modeling trajectory like Einstein changed physics. In short, the Trough Train is the greatest model I have ever built.
     
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  20. gjslsffan

    gjslsffan Staff Member

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    Well, I gotta say this is one of the coolest model RR designs I have ever seen. It is just incredible to have seen you start the project, work your way thru it, and come I guess as close to finish as you want it to be. I think the green is a bit dark too. I dont think anyone has ever made a better BN green than Scalecoat did. But the real ones got a little dark over their service lives as well.
    I have seen the real ones in Alliance NE, and I just stood there kind of mesmerized that it would actually work at all.
    And now to see it in represented by your design efforts in HO, and have it actually work, is awe inspiring compounded.
    Most impressive efforts in modeling.
     
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