In the event any urban renewal authority or other public body shall determine that any public utility line or facility located upon, across or under any portion of a street, avenue, highway, road or other public place or way shall be temporarily or permanently readjusted, removed, relocated, changed in grade or otherwise altered (each and all hereinafter for convenience referred to as "relocation") in order to accommodate any urban redevelopment or slum clearance project undertaken pursuant to the provisions of this article, the cost of such relocation shall be borne by the urban renewal authority or other public body making the same necessary.

For purposes of this section, the term "cost of relocation" shall include the entire amount paid by such utility, exclusive of any right-of-way costs incurred by such utility, properly attributable to such relocation after deducting therefrom any increase in the value of the new line or facility and salvage derived from the old line or facility.

The cost of relocating utility lines or facilities, as defined herein, in connection with any federal-aid urban redevelopment or slum clearance project is hereby declared to be a cost of such project.

Under no circumstances whatever shall the foregoing provisions of this section be applicable to any conventional urban renewal project, urban redevelopment or slum clearance project or neighborhood development project for which an application for federal funding shall have been made prior to the effective date of this section.