1958—Pub. L. 85–640 permitted issuance of an order of apportionment of cost for entire alteration based on the accepted bid for first part of alteration and an estimate of cost for remainder of work where bridge owner proceeds with alteration on a successive partial bid basis.

1952—Act July 16, 1952, made railroads share equally with proprietors of highways in bearing cost of alterations necessary to remove obstacles to navigation.