Whenever heretofore a contractor, in connection with any public work or improvement, and his, their, or its surety, has assumed in a bond given to the Commonwealth of Pennsylvania the obligation to pay all lawful claims of sub-contractors, material-men, and laborers for labor performed and materials furnished in connection with such public work or improvement, then, in such event, the remedies as provided by section one of this act shall extend to every such subcontractor, material-men, and laborer.
8 P.S. § 147