An ABC Braking controller for DCC Model Railways, relay switched and ready to be controlled by a layout control system.

Four switched sections per board.

Install in the right rail track feed for a section where you want your trains to optionally stop, e.g. approaching a signal.

Enable your DCC Decoders ABC braking feature.

When the relay is not powered, the train will stop.

When the relay is powered, the train will not stop.

Control is via a common 12V power source and four separate control pins, pulled active-low. This is suitable for connection to many layout control systems.

If you want your trains to pull up to the signal exactly, configure constant distance ABC braking, and switch the braking on when the train is a fixed distance from the signal.

The DCC asymmetric voltage drop is created with 1n540x diodes, which have a forward current of 3A, enough to handle a pair of even the most power hungry locomotives.

Two different relay footprints are supported. Build it with your favourite relays.

Two different control pin headers are supported. Wire it in your preferred way.

There are additional holes in the DCC feeds to allow the board to also be configured for power distribution -- add wires on the board to avoid having to build a power distribution 'spider' or run several parallel wires back to the main DCC bus.