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Friday, April 4, 2014

LEGO 4-Wide Power Functions RC train v2.1

In February when I was going crazy revamping & ultimately completely redesigning my elevated rail train, I seem to have missed an update for all of you!  It was shown in my last full city walk-through, but never by itself in close detail.  Consider that problem corrected!
This is now a fully 4-stud-wide, working Power Functions IR RC train with no modified parts, running on a combination of "Indiana Jones" turns sections and built-up 4-wide narrow gauge straight rail.  The cars are as follows:
  1. "Forward" cab has no electronics, seats a driver & 3 passengers.
  2. Next is the motive / engine section with a Power Functions S motor mounted vertically on a custom dual drive axle setup.  I did cheat here with the inclusion of a small piece of lead for extra ballast.
  3. The center car has the PF IR receiver & routes its cable through the roof.
  4. Next up is a rechargeable lithium PF battery box.
  5. The last car in line is identical to the first!


  1. Hey there - I know this is an older thread - I have been running into a lot of the same struggles (weight, balance, traction, etc.) that you have with my 4-wide layout. Do you have closer pictures of your vertically mounted motor setup that you would be willing to share?

  2. Hi JANGBricks!

    I came across your remarkable elevated narrow gauge build videos with Power Functions on YouTube. Whilst I've found many narrow gauge builds, yours is the only one I've seen that's powered and with any hint at the mechanism beneath.

    I am currently designing, entirely in Lego Digital Designer, a Lego orrery (mechanical solar system model) for a public stargazing charity I volunteer at. An EV3 brick powers an axle which drives a very complex gearbox, rotating the Sun every 33 days, an Earth on an arm around the Sun every 365 days (and on it's tilted axis every 24 hours) with a Moon orbiting every 28 days.

    I've hacked the EV3 brick to run Python code on Linux and have built a graphic interface (illustrating radial velocity motion, transiting light curves, moon phases, seasons and calendar).

    I'd love to add a second planet in orbit (Mars) but this would be unwieldy on an arm or using the current gearbox. A circle of black narrow gauge track however would be perfect! I'd plan to make two train carriages: one carrying a second EV3 brick on its side as a slave to the first over Bluetooth; with the second carriage having a mounted Mindstorms motor to drive the 'train' and also rotate an attached Mars every 25hrs. Do you think this would be possible? I note your curved tracks are softened with intermediary straight tracks, but this would have to be circular. Of course an old Monorail or 6-stud railway would be simpler but would make the model unwieldy for taking in to schools and storing at the observatory.

    Additionally, if you have a Lego Digital Designer .lxf file of the wheel mechanism I would be eternally grateful!


    Dr Luke Tyas, University of Durham