What is a Third Rail?
Many trains that are powered by electricity, such as subways and other rapid transit railway systems, are attached to a third rail that runs alonside the tracks. The third rail provides electricity, which powers the train.
This is a good thing for trains. But for a person, touching the third rail means instant electrocution, or death by electrical shock.
What are Third Rail Issues in U.S. Politics?
In politics, a “third rail” issue is one that is so politically charged and controversial that any politician who dares to touch it risks destroying his or her career.
Who decided to apply the railroad term "third rail" to Social Security? And why? See Why is Social Security Called the Third Rail of American Politics?
