THE L: Short for “elevated,” as within the CTA’s elevated commuter rail system; additionally oddly refers to that system when it’s not elevated — at avenue degree or a subway. THE THIRD RAIL: 1. High-voltage electrified monitor that powers L trains. 2. A subject fraught with peril if mentioned in public, equivalent to race and faith. CTA BUS: Mass transit car that doesn't include a public toilet, although many riders appear to suppose it does.