Iowa Code § 327G.69
Whenever such spur track is so connected with the main line, as provided in this chapter, at the expense of the owner of such proposed or existing mill, elevator, storehouse, dock, wharf, pier, manufacturing establishment, and any person, firm, corporation, or association shall desire a connection with such spur track, application therefor shall be made to the department, and such person, firm, corporation, or association shall be required to pay to the person, firm, corporation, or association that shall have paid or contributed to the primary cost and expense of acquiring the right-of-way for such original spur track, and of constructing the same, an equitable proportion thereof, to be determined by the department, upon such application and notice, to the persons, firms, corporations, or associations that have paid or contributed toward the original cost and expense of acquiring the right-of-way and constructing the same.
Iowa Code § 327G.69