33 CFR § 117.215 - Niantic River.
(a) The draw of the Amtrak Bridge, mile 0.0, at Niantic, shall open on signal at all times. When a train scheduled to cross the bridge without stopping has entered the drawbridge block, a delay in opening the draw may occur until the train has cleared the block. The delay should not exceed 10 minutes.
(b) The draw of the S156 Bridge, mile 0.1, at Niantic, shall open on signal; except that, from 7 a.m. to 8 a.m., and 4 p.m. to 5 p.m., Monday through Friday, except holidays, the draw shall open only for the passage of commercial vessels. From November 1 through April 30, from 8 p.m. to 4 a.m., the draw shall open on signal if at least six hours notice is given by calling the number posted at the bridge.