Hi Yardbirdinc,
The MTH ITADS do function, but they are not the best option. The most reliable system is to use an insulated section of outside rail. If it would be difficult to add an insulated section, IR detectors are a good option. However, the MTH IR detectors are very finicky. Most IR detectors, including the MTH ITADS's, come with a sensitivity adjustment. In the case of the MTH ITAD's, if you adjust them to work properly with the room lights on they will never trigger with the lights off. Conversely, if you tune them to work with the lights off, they will be constantly triggered with the lights on. This is especially problematic in train rooms with lots of windows. Z-stuff makes much better IR detectors, such as the DZ-1075 and DZ-1075m that are far less sensitive to changes in ambient light levels.