Should there be a street, electric, interurban or steam railroad track or tracks on any street, alley, avenue, or highway improved under this chapter, the cost of such improvement between the rails and the spaces between such tracks and eighteen inches (18") beyond the outer rail, including switches and turnouts, shall be paid by the owners of such railroad, and shall be assessed and collected from such owner, and shall be a lien upon the railroad and the property used in connection with the railroad and the property; provided, that where any such railroad shall occupy any street, alley, or highway under ordinance or contract with the municipality, it shall pay or improve according to such ordinance or contract, as is provided in §7-32-113.