In Boston it is also the T (properly stylized as T⃝ if you have a good Unicode renderer). It doesn't stand for anything (it's run by the MBTA, and it's not eve

In Boston it is also the T (properly stylized as T⃝ if you have a good Unicode renderer). It doesn't stand for anything (it's run by the MBTA, and it's not ever called anything but "the T"), though Wikipedia tells me the logo is modeled after that of Stockholm's.