RFID-based model railroad lighting system

I have yet to find a satisfactory grade crossing for model railroads - they are sometimes done by a physical trigger system on the rails, and occasionally done with optical systems (see link).

By the same token, it's difficult to find a system that can be built into a large-scale model railroad that changes the overhead lights as a train passes under them to add a semblance of realism (real railroad geeks would notice that a light signal on a real railroad changes from green over red to red over red when a train passes below it).

The advent of RFID tags provides a way to solve both problems.

The user places a unique RFID identifier on each car, or simply on the trailing and leading cars (not on the engine, because of the electromagnetic motors that drive the engines). An RFID scanner is placed between the rails at wayside signals and ahead of grade crossings. As the lead car passes over the scanner, the scanner and an associated program tell the lighting systems what to do. The leading car turns on grade crossing lights and bars, or causes the wayside signals to change.

The trailing car turns off the grade crossings, or farther down the track passes a scanner that tells the program, and vicariously the wayside lights, to return to a particular pattern.

Those with the wherewithal to do so could use unique identifier tags for each car, to track their locations.

RFID tags would be applied to the bottoms of cars, probably using some sort of re-usable glue, or could be placed inside the car body (most model railroad cars can be separated into body and base).