can i use the boston T in my art work. is it trademarked. what about images of public school & government buildings

Maps are copyrightable, and the MBTA owns the copyrights to its maps of the T and restricts use by others.

Public buildings, including schools, are different. Images of them in photos or paintings aren't subject to copyright restrictions, so you can use them all you like.

Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.

Were you referring to the T train cars themselves? Those are most likely not protected art either.