Feed near Leithton monitors AAR 054 054, which is the end-to-end channel for the CN Waukesha, CN Leithton, and CN Waukegan Subs. From this position, most radio traffic between State Line and Deval on the Waukesha Subdivision is received, plus Leithton to Barrington on the Leithton Subdivision, as well as the Waukegan Sub.