Mass. Gen. Laws ch. 160 § 122
The master of a vessel applying to pass such draw shall give to the draw tender a true report of his vessel's draught, and of anything projecting below such vessel's draught, and shall be governed by him as to priority of right if two or more vessels apply at the same time to pass. In passing, he shall, unless otherwise directed by the draw tender, go to the right according to the tide, if practicable, and shall so place his warping-lines, anchors, cables and other rigging and equipment as neither to interfere with other vessels nor obstruct or injure the bridge; and he shall be allowed a reasonable time for his vessel to pass. A railroad train shall be allowed fifteen minutes to cross a draw before and after it is due by its time table, and any approaching train shall be allowed a further reasonable time to pass.
Mass. Gen. Laws ch. 160, § 122