For the purpose of meeting those expenses required to be assumed under subsections (a) and (b) of this section, the Secretary of Transportation shall issue to the Secretary of the Treasury such obligations in such forms and denominations, bearing such maturities and subject to such terms and conditions, as may be prescribed by the Secretary of Transportation with the approval of the Secretary of the Treasury. Such obligations shall be at a rate of interest as determined by the Secretary of the Treasury, taking into consideration the average market yield on outstanding marketable obligations of the United States with remaining periods of maturity comparable to the average maturities of such obligations during the month preceding the issuance of such obligations of the Secretary of Transportation. The Secretary of the Treasury shall purchase any obligations of the Secretary of Transportation issued under this subsection and, for the purpose of purchasing such obligations, the Secretary of the Treasury may use as a public debt transaction the proceeds from the sale of any securities issued under chapter
31 of title
31 after December 23, 1985, and the purposes for which securities may be issued under such chapter are extended to include any purchases of the obligations of the Secretary of Transportation under this subsection. All redemptions and purchases by the Secretary of the Treasury of the obligations of the Secretary of Transportation shall be treated as public-debt transactions of the United States.