Update: 12/19/2024, New wheel and coupling rod design to prevent jamming! This design change only requires 4 new wheels and 2 new coupling rods to be printed; all other previous parts can be used. The design now utilizes screws to connect coupling rods and follower wheels. To get more consistent operation, I would also suggest using no more than 2 carts.
This fully functional train prints without any support on any of the parts! All parts are fully 3D printed except the motor, switch, 4 screws, and the battery holder. All other wheels, axles, tracks, etc., are snap-fit together. There is a common train cart base for the regular cart top and caboose. This creates an opportunity for anyone to design their own cart topper.
For Part name references, refer to the “Train KeyUPDATE” PDF below
(This one had a lot of extra parts, and these components are fairly standard, so feel free to source from other places.
I used the screws from the scraper kit included with my Bambu printer. These screws are also available at the Bambu store (Linked below).
Assembly Steps:
Fit the motor into the train housing by first sliding the back end of the motor towards the rear of the train. You will then twist the motor until one of the axle sides is poking out of the wheel hole. Push down the other side of the axle until it is locked in place.
Wire the switch, motor, and battery pack by sodering one of the wires straight to the motor and then adding the switch in between the second wire and the motor. MAKE SURE to test the spinning direction before soldering. (The switch will slot into the back of the train; you will want to route the wires through the channel before soldering in place.
Add the drive wheels by pushing them onto the motor drive shafts; make sure they are pushed as far onto the shaft as possible WITHOUT rubbing against the body.
Push the screws through the coupling rods before threading them into each wheel. Ensure the screw is perpendicular to the wheel when inserting. Thread the screw into the wheels as far as possible, then back them out until there is no friction.
Push the wheel pins through the follower wheels (ensure they spin freely.) Push pins/wheels into the four corner holes in the train
Snap the battery holder in place in front of the motor
The cover will slide into place and lock when pressed firmly into the recess
Finally, fit the smokestack into the top of the cover, ensure the curvature is aligned
Cart Assembly
Components
Cart Platform x1
Cart Wheels x4
Cart Pins x4
Cart top(Regular or Caboose) x1
Assembly Steps:
Place the wheels between the posts on the bottom half of the cart platform; ensure the ridge of the wheels is on the inside
Insert the cart pins into the platform wheel slot, through the wheel, and snap them in place into the platform
Make sure the wheels rotate freely; otherwise, pull the pin out and sand the pin slightly
You can now place the cart tops onto the base; this base will work with the caboose and regular carts
The caboose will have a separate middle “collar” piece that will snap into the caboose's body and then into the cart platform. This was done in order to print without any supports
Track Assembly
The track snaps together in a vertical fashion. Hold one piece over the other and align the circles, then push down. There are only two types of track pieces. The first is a standard straight piece, and the other is a 22.5-degree curved piece. You can snap these curved pieces together in either direction to get the train to turn at different degrees. I really like the improved solution the community came up with to better hold the tracks together. I would recommend printing those connectors as well.
Building your own cart top!
Dimensions of cart base:
62mmx100mm outer rim
The lip offset 4mm from the outer rim, and it is 2mm wide
This slot is 3mm deep
Build something cool; happy printing!
*NOTE: If you need more traction, add more weight to the train engine. (I added an extra 2 AA batteries)
Willmck
