CHICAGO (CBS) — New security measures have been announced to improve safety on CTA trains, under a federal counter-terrorism initiative.

CBS 2’s Susanna Song reports, starting Nov. 3, if you ride the “L,” prepare to be asked to hand your bags, purses, or suitcases to a Chicago police officer to be screened for explosives at some stations.

Passengers will be selected at random before passing through turnstiles at CTA train stations.

Police officers with a mobile explosive screening team will swab bags and place the sample in a machine to check for explosive compounds. Bags will not be opened. The test takes only about 30 seconds.

“We know the fears and the possibilities. It’s going to take 20 to 30 seconds of someone’s time. While we know our commuters’ time is precious, we think their safety is probably priceless,” Chicago Police Public Transportation Cmdr. Nancy Lipman said.