; and port infrastructure investments (including inland port infrastructure and land ports of entry): Provided further , That of the amount made available under this heading, the Secretary may use an amount not to exceed $15,000,000 for the planning, preparation or design of projects eligible for funding under this heading: Provided further , That grants awarded under the previous proviso shall not be subject to a minimum grant size: Provided further , That the Secretary may use up to 20 percent of the funds made available under this heading for the purpose of paying the subsidy and administrative costs of projects eligible for Federal credit assistance under chapter 6 of title 23, United States Code, or sections 501 through 504 of the Railroad Revitalization and Regulatory Reform Act of 1976 ( Public Law 94–210 ), as amended, if the Secretary finds that such use of the funds would advance the purposes of this paragraph: Provided further , That in distributing funds provided under this heading, the Secretary shall take such measures so as to ensure an equitable geographic distribution of funds, an appropriate balance in addressing the needs of urban and rural areas, and the investment in a variety of transportation modes: Provided further , That a grant funded under this heading shall be not less than $5,000,000 and not greater than $25,000,000: Provided further , That not more than 10 percent of the funds made available under this heading may be awarded to projects in a single State: Provided further , That the Federal share of the costs for which an expenditure is made under this heading shall be, at the option of the recipient, up to 80 percent: Provided further , That the Secretary shall give priority to projects that require a contribution of Federal funds in order to complete an overall financing package: Provided further , That not less than 30 percent of the funds provided under this heading shall be for projects located in rural areas: Provided further , That for projects located in rural areas, the