Section 73. The amount of any expenditure under section eighty by a street railway company toward the cost of abolishing a grade crossing shall be deemed and taken in all proceedings thereafter as a part of the value of its property for street railway purposes; and such company may issue stocks or bonds to such amount as the department of telecommunications and energy shall, subject to the laws relating to the issue of stocks and bonds by street railway companies, approve as reasonably necessary to provide for the payment of such expenditure.