The device is a body scanner much like the ones found in airports across the country. "Obviously, jails and prisons have a huge contraband problem," said Metro Corrections Director Mark Bolton.

Body scanners in L.A.'s transit stations? Metro and TSA are testing technology that could make it possible — without the need to erect an airport-style checkpoint.

Metro rolled out scanners at Union Station earlier this month as part of a pilot program aimed at getting weapons off the transit system, even though a similar effort in New York City faced scrutiny.