Google: the WalMart of the internet. Why go to your local transit company's website when you can just google the same information?
Have you given that a serious try, lucy? I have, and it's a frustrating and dismal experience, at least in the US. Transit schedules are so badly maintained on most websites that it verges on criminal neglect.
Chances are, also, that this entire data subset integrates also with the Google Now [google.com...] real time infrastructure...
[Google Now] tells you today’s weather before you start your day, how much traffic to expect before you leave for work, when the next train will arrive as you’re standing on the platform, or your favorite team's score while they’re playing.
...and Google is not about to waste a bit of data.
Also, as the googleblog article reports it, the feature they describe is integrated into Google Maps for Android, which your local transit company's website isn't.