AirWire is a popular wireless control system for large scale model railroad locomotives and accessories. A handheld transmitter is used to control train speed, lights, sound, and trackside accessories. Analysis of this system revealed that the protocol is based on the DCC (Digital Command Control) standard used for powering and controlling trains through conductive track, but instead transmitted over 900-MHz ISM band channels as a continuous FSK stream. Transmitters and receivers both use the popular CC1101, but in asynchronous mode - bypassing its packetization functions. This presentation will detail the reverse engineering process and show how to the presenter built his own custom hardware to interact with this system.