Conn. Gen. Stat. § 14-249: Stopping at grade crossings.

(a) An operator of a motor vehicle shall bring his or her motor vehicle to a full stop at a railroad grade crossing when warned of an approaching locomotive or a train by a law enforcement officer or flashing lights erected at such grade crossing pursuant to an order of the Commissioner of Transportation and shall refrain from passing over such crossing until the approaching locomotive or train has passed such crossing.

(b) An operator of a commercial motor vehicle shall refrain from passing over such grade crossing, regardless of whether flashing lights are erected or are operable at such grade crossing, unless all tracks are clear.

(c) An operator of a commercial motor vehicle shall, upon approaching a railroad grade crossing, drive such motor vehicle at a rate of speed that will enable such motor vehicle to be stopped when required by the provisions of subsection (a) or (b) of this section or section 14-250.

(d) Violation of any provision of this section shall be an infraction.