Extreme Heat Prompts Safety Advisory on Track-Buckling
The new advisory cites "unusually high, and prolonged, record-breaking temperatures" and highlights a recent series of derailments thought to have been caused by buckling.
The Federal Railroad Administration has issued Safety Advisory 2012-03 to remind railroads to be particularly vigilant about potential buckling of continuous welded rail segments of their track. Published July 16 in the Federal Register, the advisory says "unusually high, and prolonged, record-breaking temperatures" have affected much of the United States recently, and these conditions can cause buckling.
Four derailments in June and July are thought to have been caused by buckling, it says, saying these are preliminary determinations, however. The four incidents listed are a June 23 derailment of 22 cars in a Union Pacific train at Bill, Wyo.; a July 2 derailment of 31 BNSF coal cars in Mesa, Wash.; and two July 4 derailments -- 31 coal cars in a Union Pacific train at Northbrook. Ill., and 43 BNSF coal cars in Pendleton, Texas.
Incidents where rail buckles because of extreme heat are called "sun kinks." A December 2010 Research Results report from FRA about them says a major problem with continuous welded rail is an almost complete lack of expansion joints in it to accommodate seasonal thermal changes. The report discussed research being done at that time to measure stress in CWR using ultrasonic waves.
Rail buckling caused 48 derailments and nearly $30 million in direct costs in 2006 alone, according to the report.