Big Bayou Canot train disaster

Infobox rail accident


title= PAGENAME
date= 02:53, September 22, 1993
location= Mobile, Alabama
coordinates= coord|30.8173|N|87.9932|W|
line = CSX Transportation
cause= barge collision with bridge
trains= "Sunset Limited"
pax= 220
deaths= 47
injuries= The Big Bayou Canot train disaster of September 22, 1993 is the worst train wreck in the history of the United States passenger railroad company Amtrak. In terms of fatalities and destruction, this wreck substantially exceeded the severity of the Chase, Maryland accident that occurred in 1987.

This wreck occurred after a CSX Transportation swing bridge over the Big Bayou Canot in southwestern Alabama (about 10 miles northeast of the city of Mobile) was struck at approximately 2:45 AM by a barge being pushed by the towboat "Mauvilla", whose pilot had become disoriented in heavy fog. The collision forced the bridge approximately three feet out of alignment and severely kinked the track.

At approximately 2:53 AM, Amtrak's "Sunset Limited" train, powered by three locomotives (one GE P40DC number 819 and two EMD F40PH, numbers 262 and 312) en route from Los Angeles, California to Miami, Florida with 220 passengers and crew aboard, crossed the bridge at high speed and derailed at the kink. The locomotives slammed into the bridge superstructure, causing its destruction. The lead locomotive embedded itself nose-first into the canal bank and the other locomotives, as well as the baggage car, dormitory car and two of the six passenger cars, plunged into the water. The locomotives' fuel tanks, each of which held several thousand gallons of diesel fuel, ruptured upon impact, resulting in a massive fuel spill and a fire began to engulf the train. Forty-seven people, of whom forty-two were passengers, were killed, many by drowning, others by fire/smoke inhalation.

Immediately prior to the accident, the "Mauvilla" had made a wrong turn and entered an un-navigable stretch of water. The towboat's pilot was not properly trained on how to read his radar and thus, owing to the very poor visibility in the fog, did not realize that he was off-course. Although he was aware that he had struck something when his tow collided with the bridge, his initial supposition was that one of the barges had merely run aground.

The bridge span had actually been designed to rotate so it could be converted to a swing bridge by adding suitable equipment. No such conversion had ever been performed, but the span had not been adequately secured against unintended movement. Despite the displacement of the bridge, the continuously welded rails did not break. The result was that the track circuit controlling the bridge approach block signals remained closed and the nearest signal continued to display a clear (green) aspect. Had one of the rails been severed by the bridge's displacement, the track circuit would have opened, causing the approach signal to display a stop (red) aspect and the preceding signal an amber approach indication. This might well have given the Amtrak engineer sufficient time to stop his train or at least reduce speed in an effort to minimize the severity of the accident.

Analysis

An episode of the National Geographic Channel documentary series "Seconds From Disaster" examined this accident in detail.

* Although there were signals on the line operated by track circuits, the long welded rails did not break and did not cause the bridge approach signal to change to red. Had jointed rails still been fitted, the signal may well have dropped to red, as such rails would more likely have broken at the joints.
* The span had actually been designed to rotate so that the bridge could be converted to a swing bridge by installing a motor and control equipment, if it were ever decided that barge traffic warranted this. No such conversion had ever been done and the span's lack of lateral rigidity was a contributing factor to the accident.
* One span of the bridge was pushed so far out of position that the kink in the line caused the derailment. The span was not fitted with "straps" to keep it in reasonable alignment with other spans of the bridge. Had such straps been fitted, the kink in the line might have been less severe and less dangerous.
* Had barge traffic posed a regular hazard, special barge collision detection circuits could have been fitted to shunt the signals to red in case of a collision. But the Big Bayou Canot is not navigable, so this seems nearly pointless.
* Perhaps the bridge could have been protected by sacrificial piers, although the existing piers did not move upon impact.
* It is likely that the size and number of barges pushed by one tug had increased over time in excess of what the bridge could handle in a collision.
* As a result of the accident, barge pilots are now required to be trained in the use of radar.
* In post accident analysis, the NTSB, again, called for Amtrak to implement an accurate, on board passenger enumeration ability. Amtrak now records passenger lists electronically

Similar accidents

There have been numerous incidents throughout the world involving bridge collisions, including the following.
* The 1953 Tangiwai Bridge disaster in New Zealand, in which 151 people died when a bridge over the Whangaehu River collapsed. Sensors now put the signals to red if the river level rises too high.
* The 1975 Tasman Bridge disaster in Hobart, the capital city of Australia's island state of Tasmania, when a bridge was hit by a 7,000 ton bulk carrier, causing a 400 foot section of roadway to fall 120 feet into the river below. Twelve deaths resulted.
* The 1977 Granville train disaster in Sydney, Australia, which involved the collapse of a bridge after its support pylons were struck by a train. This incident was caused in part by inadequately protected and strapped piers and spans. Programs to protect piers of some other bridges were instituted.
* The Eschede train disaster had flimsy piers like the Granville accident. Lessons from the Granville disaster were apparently not put in place.

External links

* [http://www.ntsb.gov/publictn/1994/RAR9401.htm NTSB summary of the accident]
* [http://www.trainweb.org/vangab/bigbayou.htm Trainweb page on the accident, including photos]