The bottom timbers of all bridges constructed over any railroad track shall be not less than eighteen feet above the rails, unless the Commissioner of Transportation requires a lesser height and prescribes the same in writing.
Conn. Gen. Stat. § 13a-130
(1949 Rev., S. 2124; 1958 Rev., S. 13-8; 1963, P.A. 226, S. 130; P.A. 75-486, S. 33, 69; P.A. 77-614, S. 571, 587, 610; P.A. 78-303, S. 85, 136.)