Google Maps features over 1 million public transit stops in over 500 cities

"Since 2005, we’ve collaborated with hundreds of transit authorities around the world to make a comprehensive resource for millions of riders to find out which bus, train, subway or tram can take them to their next destination. Today, Google Maps has public transportation schedules for more than one million transit stops worldwide, in nearly 500 cities including New York, London, Tokyo and Sydney.
Public transportation information is especially useful when it’s in the palm of your hand. Today we’re releasing an update to the Google Maps for Android app (version 6.10) which makes this transit information even more useful. We’ve made some changes to the Transit Lines layer, so that you can select a specific mode of public transportation (train, bus, tram or subway) to display on the mobile map, hiding the other modes. This is helpful in areas where there is a tight concentration of several types of public transit."

Source:  Google blog, 15th August 2012