I just got this notification on iOS 9.1 that transit directions are now available for Washington D.C. and Baltimore. Didn't know if anyone else has seen these notifications before for any other cities near where they live (I'm in the D.C. area).
"At launch, transit directions will be available in Baltimore, Berlin, Chicago, London, Mexico City, New York City, Philadelphia, San Francisco, Toronto, and Washington D.C. It will also be available in 30 cities in China, including Beijing, Shanghai, and Shenzhen."
Some strange omissions there, but I guess they had to start somewhere. Hopefully Apple will update it rapidly.