Rail Infrastructure Development and Expansion Act for the 21st Century - Amends federal transportation law to authorize the Secretary of Transportation to designate high-speed rail infrastructure bonds if: (1) the bonds are issued by a state, or one or more of the states that have entered into an interstate compact under the Amtrak Reform and Accountability Act of 1997, or by such compact; (2) they are for financing projects that make a substantial contribution to providing the infrastructure required to complete a railroad passenger transportation corridor for high-speed intercity rail passenger service, or for projects for the Alaska Railroad; (3) for a railroad passenger transportation corridor design that includes the use of freight railroad rights-of-way, a written agreement exists between the applicant and the freight railroad regarding such use and other conditions are met; (4) the corridor design eliminates all existing railroad grade crossings that would impede high-speed rail operations; (5) the applicant agrees to comply with certain labor standards with respect to such project; and (6) the applicant agrees not to pay the principal or interest on the bonds using funds derived directly or indirectly from the Highway Trust Fund, except as permitted by existing law. Excludes the interest on such bonds from an individual's gross income.
Requires any entity providing high-speed intercity passenger railroad transportation to negotiate over hiring and working conditions with the collective bargaining agent or agents of the employees of any existing rail passenger service it might be replacing.
Amends the Internal Revenue Code to allow certain tax credits to holders of qualified high-speed rail infrastructure bonds.