SECTION 1.  Notwithstanding the provisions of any general or special law to the contrary, the Massachusetts Bay Transportation Authority may enter into an agreement with the New Hampshire Department of Transportation to extend or expand commuter rail service on the New Hampshire main line, so called, in which said department agrees to provide all capital and operating costs for said service.  Said agreement may provide for the rehabilitation of the rail line north of the city of Lowell, the provision of a layover facility in the city of Nashua, New Hampshire, and the provision of operating rights over those portions of the right of way not currently owned by the authority.  The commonwealth and the authority shall not incur any costs associated with any provisions enabling extension or expansion of commuter rail service on said line pursuant to said agreement.  Within 60 days of the execution of the agreement, the authority and the department shall submit a written copy to the joint committee on transportation for its review.