Working model railway level crossings

Another long term desire has been to make working scale level crossing lights. Not just have them look pretty, but make them work as per the prototype. That is, be activated by an approaching train and switch off after the last vehicle passes the road crossing. It is just not that simple though. The train needs to be detected, operate the lights accordingly and be ready for the next train - from either direction on a single line, or work on a multiple track scenario.

On a single line track, trains can approach from either direction. That makes a complicated process for a circuit to decide when to activate and deactivate the lights. I did spend hours working out a circuit using relays, but while it worked, is clumsy in this digital age. Over the last few months, with short periods of brainwaves and head-scratching, I finally cracked it! A lot of time has been spent to date - working out the programme, design a circuit board, buy the parts, make a prototype and fine-tune that. The end result is basically here!

There will be 1 single module that can be configured in a number of different ways:
* For any number of multiple tracks where the train runs in a single direction
* For single lines, bi-directional train running.

This module does not detect the train, that is a separate function. The crossing module has 3 inputs for the "up train" approach (or "down train" departure), the actual road crossing itself, and the "up train" departure (or "down train" approach). For example, as an UP TRAIN approaches, the lights activate, and stay activated until the last vehicle clears the road. Once it clears the departure side, the circuit is ready for the next train from either direction.

Features:
*9V to 12V AC or DC power supply input
*power indicator
*on-board flashing LEDs to indicate circuit is functioning
*2 sets of outputs for LEDs on the layout.

The other concurrent project is train detectors - I am experimenting with a device that is about 3mm wide x 7mm long that will be positioned as a sleeper and detect trains optically, in all light conditions. It is not too far down the track... Current detectors will also be on the drawing board - I have already experimented with these but yet to test on a DCC layout. I don't expect any problems there though, but still need to try it out.

At the end of the day, there will be: Detectors - optical - current detections Signals - working automatically based on track occupancy Level crossings - single or multiple track modules.

***** PDF versions of block diagrams here:

Multiple track module block diagram (3MB)

Single line module block diagram (3MB)

Prototype module:

Prototype level crossing module

Prototype level crossing module

Incomplete HO scale brass level crossing signal - etched lamp backboards

Incomplete HO scale brass level crossing signal

As things progress, I will update this page.

Below, the complete 3 aspect signal module. It has inputs from track blocks and the circuitry determines the appropriate indications. Please contact me for further information or to purchase.

Check out my photo page of railway/railroad level crossings around Australia.

© Robert Parnell