Section 76.46 - Powers of investigation(1) The department may, whenever in its opinion such action is necessary, examine or cause to be examined the books and records of any railroad company or car line company in order to verify the accuracy of the reports submitted to the department.(2) If any railroad company defined in s. 76.02, or any car line company defined in s. 76.39, refuses or neglects to make any reports required under subch. I, or refuses or neglects to permit an examination of its books and records, accounts and papers, when requested so to do by the department, or refuses or neglects to appear before the department in obedience to its summons, it shall be estopped to question or impeach the action or determination of the department, or validity of any assessment made by the department.(3) No such company shall be allowed in any action or proceeding to question the assessment and taxation of its property as determined by the department, unless it has made and filed with such department a full and complete report of the facts and information prescribed by law and called for by the department.