Abstract: A method and a gage for testing uncoupling tools to ensure proper operation prior to use. The uncoupling tool gage simulates the actual conditions under which the uncoupling tool is expected to perform. The gage has a cylindrical guide for slidably receiving a magnet housing. The guide is supported such that it is concentric with respect to the probe of an uncoupling tool to be checked. The magnet housing is placed inside the cylindrical guide and then moved toward the bottom thereof. When the magnet moves into proximity with a switch in the uncoupling tool probe, an indicator lamp in the uncoupling tool illuminates. If the face of the magnet housing is within a range band on the outside of the guide when the indicator is illuminated, then the uncoupling tool is operating properly.