Wis. Stat. § 86.11
Whenever any highway crosses a railroad at grade and the town, village or county board or the city council or city commissioners other than in a city of the first class, as the case may be, shall deem it for the best interest of the public that said highway and railroad shall cross at separate grades, and when an agreement can be made between such board and the railroad company as to the manner of constructing of such separated grade crossing and doing the necessary work they may contract therefor; and such board shall after entering into such contract levy a tax sufficient to raise the money required to carry out such contract on its part, which tax shall be collected at the time and in the manner as other taxes are, and when collected shall be set aside as a special fund and used for said purpose. The plans for such grade separation shall have the approval of the department before the contract shall be binding or the change shall be made.
Wis. Stat. § 86.11