Conn. Gen. Stat. § 16-217: Securing of bonds by mortgage.

Any railroad company may secure its lawfully issued bonds by a mortgage of its property, or any part thereof, by deed executed by its president, under the corporate seal, to the Treasurer of the state and his successors in office, or other trustee, in trust for the holders of such bonds. Such mortgage shall be recorded in the office of the Secretary of the State and need not be recorded in the records of towns within which the property so mortgaged is situated.