You're at the station, waiting for the afternoon express. The train should've been here ten minutes ago...when will it arrive? Thanks to Google Maps, you'll now be able to find out--well, in a few cities, at least.

The desktop and mobile versions of Google Maps now feature live train and bus departure times and service alerts for six U.S. and European cities, including Boston, Portland, Ore., San Diego, San Francisco, Madrid, and Turin. Google will add more cities in the near future.

The service alerts indicate if there's a detour, construction delay, or some other snafu that's causing your bus or train to run late.

Before leaving work, you can check Google Maps to see if your bus or train is on time. The live alerts appear when you click a transit icon or search for a station.

Mobile users can check live departures by tapping a Google Maps transit icon, and pulling up information for their station. The maps displays service alerts too.

The newest version of Google Maps for Mobile requires Android 1.6 or newer. No downloads or updates are necessary to access live transit updates.