On this page, we collect tips and tricks around building and modifying LEGO train tracks and compatible.

Note: the instructions on this page ,may be used on your own risk only.

Trixbrix R40 Curved Switches

The curved switches from Trixbrix are fantastic and allow to fork or switch tracks on limited space. However, there is a drawback that comes with those switches: locos and cars easily derail when pulling from the peak to the outer curve of those switches. The reason is that these switches do not come with guard rails (check rails) on the outer track to prevent the axles from being pulled to the inner side of the curve, thus derailing on the frog.

Former Mattzobricks Core Development Team member Hilbert has created a small 3d printed part, that can be mounted on the switch and acts as a railguard to prevent those derailings.

Guard rail for Trixbrix R40 Curved Switch
Guard rail for Trixbrix R40 Curved Switch

The part designed for left R40 curved switches. For right curved switches, just mirror the part in your 3d slicer program before you print it.

Download guard rail for Trixbrix R40 curved switches .stl file

Thank you, Hilbert.


If you want to convert a standard LEGO switches to meet the Trixbrix R40 geometry pattern, these instructions might help you.

This is what you need:

  • Standard LEGO switch
  • Standard corner (R72)
  • A stable pad
  • Some 2×4 plates
  • Sharp knife, e.g. a utility knife
  • Gloves (recommended)

Please be aware of your fingers and handle with care!

Thank you Max for this contribution.

The easier version is of course to just order some R40 switches at Trixbrix.eu.

Theorem of pythagoras, LEGO edition

A nice visualization of the three most important Pythagorean number triplets:

3^2 + 4^2 = 5^2
5^2 + 12^2 = 13^2
8^2 + 15^2 = 17^2

The numbers are useful to apply advanced LEGO building techniques.

Theorem of Pythagoras, LEGO edition
Theorem of Pythagoras, LEGO edition