A 3D printed caboose is needed to round out any train. That is exactly what we have for you this week. In the “real world” cabooses used to have a true function and were manned cars. But with the advent of technology, you are hard pressed to see one today on the rails. But there is something very nostalgic about a caboose, so we had to design one. We chose the “classic” Santa Fe style while developing our design, in the classic red and yellow color scheme! By this time, you have probably printed your tracks for your train, but if not, please check out our other article to start printing a layout, Adapted Designs: Let’s Make Tracks!
Let’s get started building your caboose.
Here is a list of things you will need to make your 3D printed Caboose:
- Our Caboose download. You can get it here.
- PLA filament of assorted colors. If you are going for the Santa Fe look like we did, this is what we used:
For the main body of the 3D printed Caboose, we used 3D Fila Red PLA.
For the yellow “strip” and Santa Fe logo, we used 3D Fila Yellow PLA.
For each truck, roof components, and chassis we used Jayo black PLA+
Solutech Silver Metal Filament for the wheels.
3. An assortment of M3 hardware which is used to secure the chassis together and secure each truck to the chassis. We used this assortment.
4. 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.
5. Some 3mm brass rods. We used these
6. Eight bearings 3x6x2.5mm, type MR63ZZ. We used these
7. M2 sized screws (2 screws, 8mm in length). We chose this one from Amazon because it gives us a good assortment
8. 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.
9. Glue for assembling some of the components as needed. We used this Acrylic Cement from Amazon, (SCIGRIP 16 10315 Acrylic Cement, Low-VOC, Medium bodied, 5 Ounce Tube, Clear).
Printing the Chassis Components
There are three components of the main caboose chassis to print:
- caboose_stairs_chassis (print (2) of this one)
You will need the files “caboose_center_chassis.stl” and “caboose_stairs_chassis.stl”. The central chassis will fit on a standard 220mm x 220mm FDM printer like this:
No supports are needed. We recommend printing this part at 100% infill, layer height .2mm.
Printing the chassis stairs is managed the same way. Print them at 100% infill, layer height .2mm.
If your printer handles bridging no supports should be required. Note: we have included two files to save you time. One contains both sets of stairs. Files (caboose_stairs_chassis_double.stl or caboose_stairs_chassis.stl) Once you print these three parts you can assemble the chassis.
Assembling the Chassis
The chassis is both glued and bolted into place for strength. You will need (4) M3 x 8mm screws and possibly (4) M3 nuts. During development and testing, we discovered that that the adhesive adds an added strength factor. Using the nuts to secure the self-threading screws will aid in clamping the parts together. First start by lining the chassis parts up this way:
Once you apply the adhesive, immediately secure the parts using (4) M3 x 8mm screws:
Also secure with the M3 nuts.
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)
You also want to cut the axles at this time from the brass rods. You will need four rods (two per truck). Each rod should be cut 44mm long.
To properly space the wheels, we also produced 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.
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:
- 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.
2. Slide a wheel spacer onto the axle.
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.
3. Place a bearing on each axle end.
4. Place this axle assembly over the truck so that each bearing lines up with the slot in the truck.
5. You should easily be able to push the axle down into the slot so each bearing fits in place in its respective slot.
6. Repeat the process for the other axle. You should now be ready to install the retaining clips.
Installing the Truck Retraining Clips
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:
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.
If your axle bearings are all the way in properly, the clip will then sit flush as shown.
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.
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. Please note that if you have printed our other cars the mounting block included with the caboose download is actually shorter than the other cars. If you use the other block from the other downloads the car will sit too tall. So be sure to use the included one in this download.
Installing the Magnetic Coupler
The magnetic coupler part you need is contained in our download. You want to print the file “Extended_magnetic coupler.stl”. This coupler is a bit longer than the other ones we have in used on the other cars.
The reason for this “extended” version is we found that the caboose without it would derail because it would hit the adjacent car.
Assembly first involves gluing in one of the magnets in the end of the coupler.
After the glue dries, you can install the M2 x 8mm screw into the 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 caboose.
Mounting the Finished Trucks to The Caboose Chassis
To mount the finished truck to your 3D printed caboose, you will need one M3x20mm button head screw for each truck (or similar)
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 caboose chassis.
You do not want to tighten the mounting screw tight so the truck cannot swivel. Keep this in mind. They do not need to be flush, just secure. You may also notice that the mounting blocks are shorter than our other cars (if you have built them). This is because the truck height needs to be shorter to minimize “wobble” of the caboose and to assist with its proper appearance.
Once you have the truck mounted check to make sure that it is in line with the chassis base and adjust it if needed. The mounting block will allow you to make minor corrections to the truck. In this way your 3D printed caboose chassis will sit flat on the track.
The chassis in now done. You can move on to printing the main body of your caboose.
Caboose Main Body Frame
The main body of the caboose is file “caboose_frame.stl”
Supports may be required at each window (depending on how your printer handles bridging). We recommend 60% infill at a layer height of .2mm We printed this component in 3D Fila Red PLA.
Assembling the Body Frame to the Chassis
The body frame attaches to the chassis with glue. You will be primarily gluing the ends, and if you wish, the inside lip of the frame to help hold it in place. But, before you do this, you first need to test fit the body frame, because there is a good chance one or more of the nuts you previously added will collide with the frame. So, start by testing the fit of the frame on the chassis:
It should “sit” on the stair plates. If it hits one or more nuts, try removing two from one side of the chassis. You do not need them now anyway as the glue should have set.
If the frame fits properly, glue it into place. You will want to allow the glue to dry. While it is drying you can print the next part.
Caboose Frame Top
The frame top is part “caboose_frame_top.stl”. You will want to print this part with supports:
We recommend printing it at 60% infill at a layer height of .2mm. Again, if you are going for a Sante Fe look we recommend using 3D Fila Red PLA for this part as well.
The part fits on top of the main chassis and needs to be glued. Test fit the part.
If the part fits correctly, you can glue it in place.
While this assembly is drying you can start printing the roof components.
Caboose Roof Components
The caboose roof consists of three parts:
The parts are glued in place in the positions shown above. Each of the parts are printed vertically like this using Jayo black PLA:
No support should be needed. Print them at 60% infill with .2mm layer height. They need to be printed vertically for proper printing to take place. If you look closely, you will see each of the roof parts has some sort of “lip” on them. These should be facing the build plate on the larger two parts when printing.
These lip’s function as guides when assembling them to the caboose. You should check the fit of each and glue them in place.
While this assembly is drying, you can print the final roof components which is the smokestack parts.
The smokestack consists for two pieces:
Each of these parts is printed at 60% infill, .2mm layer height, again using Jayo black PLA.
These parts are glued into the roof two part as shown:
Allow this assembly to dry before moving on to the ladder printing and assembly.
There are two ladder files included in the download:
Each of these ladders should be printed at 100% infill at .2mm layer height. You should print them this way:
Each of these ladders fits like this on the caboose and should be glued in place:
Each ladder has an offset notch which should line up with the roof line.
And the bottom of each ladder will rest on a notch at the end of each end of the car.
Only a small amount of glue is required. Allow the ladders to fully dry before moving on.
Santa Fe Logo Strip
The “traditional” Santa Fe Logo Strip is printed using Yellow PLA. You will need to print one of each of these files:
santa fe logo_side 1.stl
santa fe logo_side 2.stl
You can print both at the same time, using 100% infill at .2mm layer height.
Before you glue these on the side of the caboose, now would be a good time to print a Santa Fe decal. We have included a file for you to scale appropriately. For how to glue the decal on the PLA see our tanker article.
Once the decal adhesive is dry, glue the assemblies in place
That’s it! Your 3D printed caboose is complete!
We hope you have enjoyed the Lets Build a Train Series. If you have any other train cars or accessories you would like to see, we would love to hear from you!