Burlington Northern Trough Train

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



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.

 

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.

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.

 

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

 

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.

 

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.

 

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.

 

No worries, just had to ask!

 

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.

 

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.