Google Maps has already been pretty good at providing public transit info.
The one problem is that it only went on typical schedules.
If there was a delay or a particular route was canceled, Maps wouldnt let you know.
Now, that changes with the addition of real-time transit info.
Google is rolling out real-time public transit schedules for certain areas.
Mind the (g)app for real-time transit information| Google Maps Blog viaAndroid Police