Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 93, § 32

Sections twenty-nine to thirty-one, inclusive, and section thirty-three shall not apply to signs or other devices on or in the rolling stock of any common carrier, nor shall said sections apply to signs or other devices on or in stations, subways or structures of or used by any common carrier unless such signs or devices are displayed within view of a public way.