Any manufacturer or remanufacturer obtaining certification under this part shall supply to the Administrator, upon his/her request, a reasonable number of production locomotives or locomotive engines, as specified by the Administrator. The maximum number of locomotives or locomotive engines that may be supplied to the Administrator is five per model year. The locomotives or locomotive engines shall be representative of the engines, emission control systems, and fuel systems offered and typical of production locomotives or engines available for sale, or use by railroads, under the certificate. These locomotives or engines shall be supplied for testing at such time and place and for such reasonable periods as the Administrator may require.