Rolling Stock Protection Act This bill eliminates an exemption from the prohibition on using a type of federal financial aid to procure rail rolling stock for use in public transportation from certain manufacturers. Such prohibited manufacturers include ones that, among other things, are owned or controlled by a company based in a nonmarket economy country that is flagged for monitoring by the Office of the U.S. Trade Representative. Currently, this exemption applies to contracts made prior to the enactment of the prohibition.