National Capital Transportation Amendments Act of 1990

National Capital Transportation Amendments Act of 1990 - Amends the National Capital Transportation Act of 1969 to authorize appropriations to the Secretary of Transportation for completion of the Adopted Regional System (Washington Metrorail System). Requires local participating governments to provide a matching share of 60 percent of the Federal share of completion costs.

Reaffirms the commitment of the Congress to the construction of the full 103-mile Adopted Regional Metrorail System in a continuing partnership of the Federal, State, and local governments in the metropolitan Washington region. States that it is the intent of the Congress to ensure continued Federal funding to complete the full Metrorail system.

Prohibits the appropriation of Highway Trust Fund moneys for the construction of the Washington Metrorail System.

Requires the Washington Metropolitan Area Transit Authority to report to the Congress on rail system contracts it enters into with foreign entities in FY 1991 and 1992 which are subject to Buy American provisions of specified Federal laws or which meet such provisions but are in violation of an international agreement to which the United States is a party. Requires the Secretary to bar individuals determined to have fraudulently used "Made in America" labels from receiving a Federal contract with the Transit Authority for its rail system for from three to five years.

Prohibits a foreign government from receiving a rail system contract from the Transit Authority if such government unfairly, significantly, and persistently discriminates in government procurement against U.S. products and services and such discrimination results in identifiable harm to U.S. businesses.