Section 117.484 - Pass ManchacThe draw of the Canadian National/Illinois Central Railroad automated bridge, mile 6.7, at Manchac, operates as follows:
(a) The draw is not constantly manned and the bridge will normally be maintained in the open position, providing 56 feet vertical clearance above mean high tide to the raised tip of the bascule span for one-half the channel, and unlimited vertical clearance for the other half.(b) Railroad track circuits will detect an approaching train and initiate bridge closing warning broadcasts over marine radio and over the Public Address (PA) system six (6) minutes in advance of the train's arrival. Navigation channel warning lights will be lit, and photoelectric (infrared) boat detectors will monitor the waterway beneath the bridge for the presence of vessels. The waterway approaches to the bridge will be monitored by closed circuit TV (CCTV) cameras.(c) Activation of the warning broadcasts also activates a marine radio monitor in the Mays Yard (New Orleans switch yard). The yardmaster will continuously monitor marine radio broadcasts on the normal and emergency marine radio channels throughout the warning period and at all times the bridge is closed. The yardmaster will communicate with waterway users via the marine radio, if necessary.(d) At the end of warning period, if no vessels have been detected by the boat detectors, and no interruptions have been performed by the yardmaster based on his monitoring of the marine radio and the CCTV, the bridge lowering sequence will automatically proceed.(e) Upon passage of the train, the bridge will automatically open. Railroad track circuits will initiate the automatic bridge opening and closing sequences. (Estimated duration that the bridge will remain closed for passage of rail traffic is 10 to 12 minutes.) The bridge will also be manually operable from two locked trackside control locations (key releases) on the approach spans, one on each side of the movable span.(f) The yardmaster will be provided with a remote EMERGENCY STOP button which, if pressed, will stop the bridge operation, interrupt the lowering sequence, and immediately return the bridge to the open position. The yardmaster will utilize this control feature in the event a vessel operator issues an urgent radio call to keep the waterway open for immediate passage of the vessel.CGD08-93-023, 59 FR 14755, Mar. 30, 1994; 59 FR 23158, May 5, 1994, as amended by USCG-2000-7223, 65 FR 40056 , June 29, 2000