3D Printed Gondola

A 3D printed gondola is a nice addition to our railway. Gondolas are multi-function cars. They can haul cargo, scrap, you name it. We designed ours to be multi-function as well. Depending on how you configure it, you will be able to use it as a flat car, a car with stakes to hold for example “fake logs” or as a car with retaining walls. It is your choice. With all these options you better start thinking of a color scheme. If you have not already done so, please check out one of our other articles to get started with things like printing a track for your train. We recommend Adapted Designs: Let’s Make Tracks!

Let’s get started.

Here is a list of things you will need to make your 3D Printed Gondola:

  1. Our 3D Printed Gondola download. You can get it here.
  2. PLA filament for the gondola main body and border. We used 3D Fila Blue PLA for the main body.


3. PLA filament for each truck, border retainer option, stakes, and undercarriage. We used Jayo black PLA+

JAYO black

     4. Solutech Silver Metal Filament for the wheels.

     5. M3 button head screws (2 screws, 20mm long) for securing each truck to the tank body.

button heads

     6. M3 “socket head” screws (4 screws, 16mm long) for the trucks themselves. We liked the look of these instead of using the same hardware type throughout. Read below to see why.

socket heads

7. Some 3mm brass rods. We used these

8. Eight bearings 3x6x2.5mm, type MR63ZZ. We used these 

9. M2 sized screws (2 screws, 8mm in length). We chose this one from Amazon because it gives us a good assortment 

10.  Some 5mm diameter x 1mm tall magnets. We used these for our custom coupler. There are many vendors that come and go for this item, but we are sure you can find one that will work. We used these.

11. Adhesive to glue the parts of the gondola undercarriage together.

Printing the Undercarriage of The Gondola

For the undercarriage portion you will need to print the following part:


No support is required for this part, but there is a lot of fine detail. We recommend a layer height of .2mm at 100% infill as the details are so thin. For a standard 220mm x 220mm bed, we also recommend rotating the part about 45 degrees to fit it on your bed like this:


Printing the Gondola Base

The gondola base part (gondola_base.stl) should be printed with the bottom of the car facing up as shown below:

base gondola

Again, you will have to rotate the part about 45 degrees to get it to fit on a standard 220mm x 220mm FDM printer. The only supports that are required are at the very ends as shown here:


You could print the entire base at 20% infill, but to save filament, and have the car sides be stronger, we would recommend that you:

Print layers 1 thru 56 (11.38mm) at 5% infill, layer height of .2

Print layers 57 until the end at 100% infill, layer height of .2

We printed this in 3D Filla blue PLA.

Printing the Gondola Rails


Four Gondola rails are required for this build. So, you will need to print four of the part:


We recommend you print this part at 100% infill in the same color PLA as you printed the base.

We recommend gluing the rungs to the gondola base AFTER you assemble and connect the trucks. The rungs are very fragile. When you do go to connect the rungs, all that is needed is a small amount of glue placed in each hole of the base.

Configuration Options for the “top side” of your 3D Printed Gondola

We designed our gondola so that you can configure it several different ways. Depending on how you decide to build yours will determine the look. Here are all your options:

  1. As a simple “flat car”

gondola flat car config

A basic, simple flat car is the first configuration. The parts you have printed up to this point are enough to get you started. You can skip down to the Truck Printing and Assembly step.

  1. 3D Printed Gondola with Stakes:

The second configuration uses “retainer stakes.” The gondola can accommodate up to 12 stakes of this type. If you choose to use these, you will need to print out 12 of the “stake_configuration_2.stl” prints. We suggest 100% infill. Depending on how accurate your printer is, you may need to sand some of these components for proper fitment.

  1. 3D Printed Gondola with Border Retainer

gondola border config

Our favorite configuration is this one. The border adds a nice accent, and the clips do an excellent job of holding it. If you wish to build this configuration, you will need to print:

(4) of the border_retainer.stl part

border retainer

You want to print this at 100% infill. You will also need to add supports.

border supports

  1. Border retainer (gondola_border.stl)

To print the border retainer, you will need to angle the border at 45 degrees on the bed. We recommend 100% infill for this item also.

Truck Printing and Assembly

Our truck design allows for easy drop in bearing assembly. The bearings are retained instead by some clips that become part of the truck assembly instead of being forced in. Here is what you need to print for each truck assembly from our download:

Truck assembly.stl (This includes two clips, the truck, and the truck mount)

gondola-truck clips

You also want to cut the axles at this time from the brass rods. You will need 4 rods (two per truck). Each rod should be cut 44mm long.

gondola rods

To properly space the wheels, we also came up with some spacers. This takes the guess work out of how far apart the wheels need to be. You will want to print out (4) of the “Wheel Spacer.STL” file included in our download. We recommend printing them out one at a time at 100% infill.

rod spacers

One set of wheels are also necessary. We included them all in a file “wheels.stl”. We printed them using the solutech silver metal.

Here is how you assembly each truck:

  1. Install one of the wheels on the axle. If the fit is “tight”, check out our article on the GP38 truck assembly. It clearly shows a method to “press on” the wheels with ease.

wheel mount

  1. Slide a wheel spacer onto the axle.

wheel mount spacer

Then slide another wheel onto the axle butting it up against the spacer. You want to try and have equal distance on each end of the exposed axle ends.

bearing mounting

  1. Place a bearing on each axle end.

bearing mounting 2

  1. Place this axle assembly over the truck so that each bearing lines up with the slot in the truck.

truck mnt1

  1. You should easily be able to push the axle down into the slot so each bearing fits in place in its respective slot.

truck mnt 2

  1. Repeat the process for the other axle. You should now be ready to install the retaining clips.

truck done

Installing the Truck Retraining Clips

clip screws

Each of the clips require one M3 x 16mm socket head screw. First start by inserting the clip into the underside of the truck like this:

clip 1

The clip should be oriented in such a way as each of the tabs at the end of it “click” into place into the truck.

clip 2


If your axle bearings are all the way in properly, the clip will then sit flush as shown.

wheel 3

Repeat this for the other side of the truck with the other clip.

Once this is done, start threading in the M3 x 16mm socket head screws.

wheel 4

You can now see why we chose this type of screw. The socket heads fit into the recess of the truck. You do not want to thread the screw in all the way because the next step involves installing the truck mount.

Installing Truck Mount

The truck mount installs in the center of the truck between the screws you just started to thread in. It needs to be oriented so that the hole in the mount is at the bottom closest to the truck.


Here is what the proper orientation of the truck and truck mount. When you have the mount in its proper position, you will be able to thread the screws in the rest of the way.


If you cannot thread them, it is because the holes in the block are not lined up with the screw. An uncomplicated way to get them aligned (if you are having issues) is to back out the screw on one side completely and use a small jewelry screwdriver. Place the screwdriver inside the hole and into the block. This will line up the one side. Then, with the screwdriver still in the hole, thread the other bolt into the hole. Once this is done, you will be able to thread the other bolt in.


Once you are satisfied the truck mount is vertically straight, you will be ready to install the magnetic coupler.

Installing the Magnetic Coupler

The magnetic coupler part you need is contained in our download. You want to print the file “magnetic coupler.stl”. This will give you two couplers. Assembly first involves gluing in one of the magnets in the end of the coupler.


We would recommend that you build “sets” of magnetic couplers (two at a time), with two magnets “stuck together”. If you glue them each into the coupler at that time, it will ensure you have magnets that are not fighting each other.


After the glue dries, you can separate the couplers and install the M2 x 8mm screw into each coupler.


Thread the screw in until its flush with the other side.


Now install the coupler as shown above threading the M2 screw into the truck. You want to place the “Large End” facing “down as shown. You do not need to over tighten the screw. Remember, the coupler is going to swivel back and forth as your train maneuvers around curves. So, you want it to be able to do that. Your now ready to mount the truck to the gondola.

Mounting the Finished Truck to The 3D Printed Gondola

To mount the finished truck to your 3D printed gondola, first you want to glue, or just place, the under carriage in its proper spot.

You will need one M3x20mm button head screw for each truck.

g-trk mount

You will need to thread the screw in from under the truck until it is flush with the top of the truck mount as shown below.


Once this is done, you can screw it into the gondola under carriage and body.


The holes in the gondola base are shallow, so you do not need to “over do it” when installing them, or you may strip out the hole. The M3x20mm bolt heads will not be flush with the underside of the truck mount.

You do not want to tighten the mounting screw tight so the truck cannot swivel. Keep this in mind.

Once you have the truck mounted check to make sure that it is in line with the gondola and adjust it if needed. The mounting block will allow you to make minor corrections to the truck. In this way your gondola will sit flat on the track.


That’s it! Your gondola is now fully assembled.

We hope you have enjoyed our 3D printed gondola car build along. Be watching for more cars soon!


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