Panama Canal Revolving Fund Act - Amends the Panama Canal Act of 1979 to establish in the Treasury a Panama Canal Revolving Fund (the Fund). Provides that the Fund shall consist of the balance of the Panama Canal Commission Fund, the balance of funds available to the Panama Canal Commission (the Commission), the balance of the Panama Canal Emergency Fund, and certain other Commission receipts. Authorizes the Commission to incur obligations to the extent of its assets and borrowing authority. Sets forth the borrowing authority of the Commission. Provides for the calculation and payment of interest to the Fund. Adds working capital requirements to the list of expenditures of the Commission. Provides insurance coverage for unpredictable events. Authorizes using tolls from the Panama Canal to pay for working capital requirements.