Section, acts Aug. 2, 1946, ch. 753, title V, § 506,
60 Stat. 848; May 25, 1948, ch. 336,
62 Stat. 267, related to adjusting rates of tolls charged on an interstate bridge constructed or taken over by State or political subdivision thereof to provide fund to pay reasonable costs of maintaining and operating such bridge and a sinking fund to amortize amount paid for such bridge, with such bridge to be operated and maintained free of tolls after a sinking fund sufficient for such amortization had been provided.