(Article appeared on the Progressive Railroading.com web page on September 2)
Norfolk Southern Railway has petitioned the National Transportation Safety Board (NTSB) to re-examine and amend its conclusion regarding the cause of an October 2006 derailment in New Brighton, Pa.
The NTSB determined the accident — which involved the derailment of 23 ethanol-carrying cars, but resulted in no injuries — was caused by a broken rail. In its July 2008 accident report, the board said the rail fractured because of an “inadequate rail inspection and maintenance program.”
However, that conclusion is contrary to both new and previously available evidence provided to the NTSB during its original investigation, NS officials said in a prepared statement. The main focus of the investigation was an August 2006 ultrasonic rail inspection during which one of 24 ultrasonic signals was interrupted. The NTSB concluded the interruption resulted in an undetected rail defect.
A rail inspection contractor recently verified that the operator of the inspection vehicle, having observed a possible defect on an adjacent rail, immediately conducted a second ultrasonic test, NS said. The second test ensured that all 24 ultrasonic signals were being continuously sent.
The defect that ultimately led to the derailment was not detected by the ultrasonic test conducted nine weeks earlier because the defect either did not exist or was too small to be detected, NS said.
“Based on the uncontroverted, scientifically proven evidence Norfolk Southern has furnished, the NTSB lacks a factual basis to determine that our track and maintenance program is inadequate, and we urge the board to correct its erroneous conclusions,” said NS Vice President of Engineering Tim Drake.