Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 161, § 92

If a street railway crosses at the same level a steam railroad  1 where locomotive engines are in daily use, every motorman of a car upon the street railway shall, when approaching the point of intersection, stop his car within one hundred feet of the crossing; but the department may, for such term and under such restrictions as it may from time to time prescribe, modify or suspend the requirements of this section with respect to any such crossing by a street railway of a railroad built for private use under section two hundred and forty-five of chapter one hundred and sixty, or of a branch, spur or siding of a railroad built or used only for the transportation of freight to the premises of manufacturing or other industrial plants. For each violation of this section, the motorman shall forfeit ten dollars, and the company employing him shall forfeit twenty dollars.