Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 160, § 135

If two railroads cross each other at the same level, the engineer of every freight train and, if both railroads are used for passenger traffic, of every passenger train, upon approaching such crossing, shall stop his engine within five hundred feet therefrom, and shall not resume his course until signalled so to do, when he shall pass slowly over the crossing; but one stop shall be sufficient for all such crossings within six hundred feet of each other upon the same railroad. Every engineer who fails so to stop his engine shall forfeit one hundred dollars; and the corporation on whose railroad the offence is committed shall forfeit the further amount of three hundred dollars.