To connect the head shunt to the three sidings two turnouts, RR switches, are needed. Micro Engineering turnouts, controlled by Circuitron, Inc. Tortoise slow motors and Wabbit DCC decoders worked well together in my other project.
Each turnout is mechanically moved from 'clear' to 'thrown' by a Tortoise slow motor. A Wabbit DCC decoder is a stationary decoder that can control two Tortoises. The wiring connecting these components borrows heavily from the Train Thing project and documented here.
The DCC addresses and Smart Routs uses are documented in a separate section.