On this page, you find information about:
- how to build a German H/V light main signal with LEGO bricks,
- equipping the it with lights,
- automating the signal with a MattzoLayoutController.
Media
I have created a video about light main signals:
Deutsche Version:
About the signal
The signal was originally designed by Matthias Runte of MattzoBricks in 2021 and refined in 2022, 2023 and 2024. Julius Brönner contributed some valueable ideas and details in 2023.
Shape and functionality is based on the German H/V light main signal (Lichthauptsignal im H/V-System) that was common on German railroads since about mid of the 20th century.
Even though this type of light signal is being replaced by combination light signals that integrate distant signals into the main signal, the signal is still used on many railway tracks throughout Germany.
Options
The signal can be equipped with various options.
Basic function
The signal always has a green and two red lights.
Third aspect
The signal can be equipped with a third (yellow) aspect. This indicates that the train may pass with “slow speed” (40 km/h, if not otherwise commanded).
Shunting clearance
Two white digital lights indicate the “shunting clearance”. This means that the train main enter the shunting area, but has no clearance to operate on the following main track.
Signal out of order
The signal does not operate normally. Nevertheless, the train may pass a red signal under certain circumstances at a slow speed without written command.
Speed indicators
Speed indicators can be used to indicate the maximum speed from the signal on (white), or indicate that a speed limitation is ahead (yellow).
Distant signal
At the position of the main signal, a distant signal for the next main signal can be colocated.
See light distant signal for more details.
How to build the signal
(this section will be added shortly)
Required Parts
The signal can be built with standard LEGO parts and some extra parts as described below. No printed parts are required for this signal. It is required to drill holes into some of the LEGO parts. If you have a problem with this, use 3rd party parts from China instead.
Additional parts are:
- LEDs (3mm) in different colours. Quantity and type depend on the options of the signal that you like to add to your signal.
- Thin copper wire with black lace to power up the LEDs (diameter 0,15 mm).
- Basic stuff like a wire board, cables, plugs and connectors.
Lights
To equip the signal with lights, I have used 3mm LEDs in different colours. The wires are very thin, black copper wires used for model scale train layouts. The wires are led from the top of the signal through a pipe on the backside of the signal post. To prevent the LEDs from burning off and to save electrical power, you can add some resistors to limit the current through the LED. At a voltage of 3,3V, 120 Ohm should usually be a good value. Red LEDs usually require larger resistors than others. In question read the data sheet of your LEDs.
Automation
The signal is automated with a MattzoLayoutController (MLC). The MLC receives commands from Rocrail and lights up the correct LEDs for the current signal aspect.
Find more details about the MLC here.
To use the MLC with signals is described here.
In the firmware, there is an example configuration file called “MLC_conf_Complex_Light_Signals.h”. This is a configuration files designed for the MLC mega. This is a good starting point for you. Modify the file depending on the features that the variant of your signal has, and the aspects that it should be able to show.
Enjoy!
Credits
Julius Brönner contributed some details to the design of the signal.
Thank you for your contribution, Julius.