How to wire a model train layout for Digital Command Control (DCC) part III: Feeder wires and system testing By Jenny Freeland | November 20, 2009 | Last updated on November 7, 2022 Email Newsletter Get the newest photos, videos, stories, and more from Trains.com brands. Sign-up for email today! Get Updates Having trouble viewing this video? Please visit our Video FAQ page Model Railroader managing editor David Popp shows how to test circuits on a layout with a railroad amp meter and a quarter.