N.H. Rev. Stat. Ann. § 228:61

The commissioner is authorized to cooperate with other states in connection with the purchase of any rail properties within the state of New Hampshire. The commissioner is also authorized to acquire trackage rights in other states and rail properties lying in other states in order to carry out the intention and purposes of this subdivision. In carrying out the authority conferred by this section, the commissioner shall have the right to enter general contractual arrangements for such purposes, including joint purchase of rail properties with other states and entering into leases jointly with other states affected thereby.