N.H. Rev. Stat. Ann. § 82:26

Any corporation owning or operating a street railway property within this state, which is incapable under proper management of earning sufficient money to pay its operating expenses and fixed charges, including taxes and excluding interest on its indebtedness, and to provide for the necessary repairs and maintenance of its properties and adequate reserves for depreciation thereof, may be exempted from the payment of taxes to the extent and subject to the limitations of the following sections.