HIGHLIGHTS FROM THE JANUARY 2009 ISSUE
Breaking News
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Commentary
Proactive and predictive
Pinpointing problems well before a failure occurs
North American railroads and car owners are using a new process of condition-based freight car maintenance strategies designed to ensure that adverse vehicle conditions are identified and rectified.
This effort was developed under the leadership of the AAR and its member roads and its subsidiaries, TTCI, and Railinc Corp. The effort is led by the Advanced Technology Safety Initiative (ATSI) Task Force appointed by the AAR’s Safety and Operations Committee. TTCI is responsible for executing the industry’s collective research program, commonly referred to as the Strategic Research Initiatives. Over the past two decades, TTCI has led research to develop, test, evaluate, and implement wayside detector systems.
The vehicle health monitoring initiative builds on the industry’s implementation of wayside detectors to improve the safety and reliability by developing advanced technology systems to enhance train inspection. The present focus is on combinations of automated equipment to achieve a full complement of pre-departure train inspection requirements, including use of machine vision technologies.
ATSI is an effort to make the freight interchange system safer and more efficient by taking advantage of new technologies that offer sophisticated assessment of the equipment condition. This approach can enhance equipment performance and prolong infrastructure life. Railroads and other car owners are encouraged to manage their freight car fleets efficiently by performing proactive, predictive maintenance within a finite “window of opportunity” based upon sound scientific and engineering assessments. The desired outcome is enhanced performance and network safety with a net reduction in costs.
Current wayside detector systems implemented by North American railroads include wheel impact load detectors (WILD), hunting detectors, truck performance detectors (TPD), hot and cold wheel detectors, acoustic bearing detector systems (ABD), wheel profile measurement systems, brake condition monitoring systems, and cracked wheel detection systems. Currently, the number and types of detectors implemented in North America with Internet data access capability are 121 WILDs, 22 TPDs, 10 ABDs, at least two wheel profile monitoring systems, and one cracked wheel detector system. Machine vision technologies for automated car safety appliance inspection are currently being developed and are expected to be online within the next few years. TTCI’s acoustic bearing detector system (TADS®) capacity in North America has expanded to include a family of roller bearing defects called “growlers,” which are at a much higher risk of service failure.
The industry’s existing array of WILD provides the opportunity for rapid implementation of new rules for identification and removal of high impact wheels. The number of high impact wheels (generating impacts greater than 140,000 pounds) have been reduced by approximately 90%.
Estimated ATSI safety benefits
AAR and TTCI have estimated the effect of ATSI on broken wheel, broken rail, bearing-related, and truck-hunting-related accidents for Class I’s on main line track. The FRA’s safety database was analyzed for these cause codes both before and after implementation of ATSI in October 2004:
• Broken rail and broken wheel train accident rates: After 43 months, the post-ATSI accident rate was lower than the pre-ATSI rate by a statistically significant and increasing difference. The combined accident rate for the 43-month period post-ATSI implementation was 9.9% lower than the accident rate for the 43-month pre-ATSI period. The post-ATSI broken rail accident rate was 7.6% lower; the post-ATSI broken wheel rate was 17.2% lower. AAR ran a linear regression on this highly seasonal accident count for the full 11-year period of January 1997-April 2008, as a function of season (month), train-miles, and presence or absence of ATSI. The ATSI variable reduces the broken wheel and broken rail accident count by an average of about three per month on all U.S. railroads. Accident costs avoided, just for damage to track and equipment, are about $1 million per month. Regression results for the Class I’s are similar, with a reduction in main line accident count using ATSI of about two per month.
• Roller bearing failure-caused train accidents: On Jan. 1, 2007, ATSI launched an effort to identify and repair cars with defective journal bearings using information from TADS®. AAR compared derailments caused by burned-off journals from July 2005 to December 2006 and January 2007 to June 2008. The analysis included FRA cause codes E53C (journal bearing, roller bearing, overheating failure), E55C (journal fracture, cold break, previously overheated), and six accidents included in E59C (other axle and journal bearing defects) whose narratives indicated they were caused by burned-off journals. The analysis shows that accident rates for burned-off journals declined by 25-30% between the pre-ATSI period and post-ATSI period. Accident rates for burned-off journals declined by 10-20% between the pre-2007 period and the more recent period (18 months after Jan. 1, 2007, when the AAR Acoustic Bearing Detector rule went into effect). Accident rates for burned-off journals declined by 25-30% between 1990 and 1998 and 1999 and 2007 (nine years before and after January 1, 1999). The AAR rule for wheel removal due to high impact loads went into effect in 1993.
• Truck hunting train accidents: In July 2006, ATSI launched an effort to identify and fix freight cars prone to truck hunting. From 1997 to 2006, there were 72 accidents attributed to truck hunting, 66 of which occurred on main line track. Since September 2006 (through June 2008, the latest date for which there is data), there have been no such accidents on a main line, and only one, at 4 mph, in a rail yard. It may be too soon to draw conclusions, but it certainly appears as though the truck hunting initiative has had a beneficial effect.
There are several different benefits associated with wayside detector implementation, with the primary benefit being improved safety. Since the beginning of the ATSI program in 2004, the industry has realized many safety benefits.
Accidents caused by broken wheels and broken rails have been reduced by approximately 10%. The number of high impact wheels have been reduced by approximately 90%. Accidents caused by roller bearing-related problems have been reduced by approximately 25%. Accidents attributed to truck hunting have declined by almost 100%. Approximately 1,800 railcars exhibiting lateral instability at higher operating speeds have been identified for repair.
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