My son loves his Lego Duplo Intelli train, unfortunately Lego discontinued it. We have a locomotive from Lego Duplo 2933 but the cabin is missing, I wish to make a replacement part to fix it. He also wants to have a locomotive that has light, and runs on challenging layouts. No problem, dad has a 3D printer and computer that can make new one for you.
Step 1: Design
The locomotive is modelled after the diesel locomotive in LEGO® Duplo Deluxe Train Set with Motor 2933 (1995 - 2004). This particular model also has plenty of space for batteries and other electronics that is ideal for future modification. I plan to make a updated version that can be remotely controlled using Arduino.
Step 2: Gether the Parts
- TT electric motor with gear box 1
- 3xAA battery holder x 1
- 8x8x13mm 6 Pin DPDT Mini Push Button Self-locking Switch x 1
- M3x30mm screw x 2
- 5mm LED (with 500 ohm resistor) x 1
- M2x10mm self-tapping screw x 10
- M3x46mm steel rod x 1
- 30x2 mm rubber O-ring x 2
All the electric parts are available online. The rubber O-rings are fitted on the drive wheel to increase traction. I bought the rubber O-ring at the local hardware store at plumbing section. The front axle (3mm smooth rod) was salvaged from computer CD-ROM and cut to size. LED head light is optional, drill a 5mm hole at the headlight position for the LED.
Step 3: 3D Printed Parts
All the STL parts are attached, they are also available on Thingiverse, just download the files and print. I printed with PLA, use support for cabin and middle section.
Step 4: Assembly
- Put the rubber o-ring on the drive wheel
- Mount the drive wheels on the TT motor gearbox axle
- Mount the TT motor with drive wheels to the lower chassis use 2 M3x30 screws
- Mount the front wheel assembly and secure it to the lower chassis with the lower axle cover use 2 M2x10 self-tapping screws
- Wire the switch, battery box and the motor, add LED headlight
- Install the power switch with cap to the middle section body, use the power switch base and 2 M2x10 self-tapping screws
- Assemble the middle section to the lower chassis with 6 M2x10 self-tapping screws, fix the cabin to the middle section at hinge.