Somewhat related here, QSI used to offer something called a Power Guard. It was a box with some TVS diodes and some LEDs that flashed when it sensed a spike. We used them on the clubs modular layout. If you have any doubts that TVS diodes are worth the trouble, think again. The LEDS would be flashing almost continually. The most common reason is dirty track coupled with worn pickup rollers bouncing up and down on the rails. They show up on the auction sites occasionally though really not more effective than a TVS diode, they could be a good tool for keeping track of the condition of your motive power and rails.
Pete
