Mont. Code Ann. § 7-12-2156

Whenever any portion of the surface of a street is kept or used by any person, firm, or corporation for railroad or for street railway purposes, the cost and expense of making such improvements between the rails and for 1 foot on each side thereof shall be paid by the person, firm, or corporation owning such railroad; and where double tracks of railroads are laid, such person, firm, or corporation shall pay the costs of making such improvement or improvements between such tracks and between all switches and spurs.