High Performance Railway Wheel Testing

MxV Rail has been conducting two long-term tests to evaluate high performance wheel steels. The first test began in 2007 to evaluate high performance wheel (HPW) steels before the AAR Class D specifications were defined. This test was designated HPW1 and is still ongoing. The second test, called HPW2, began in 2015 to evaluate a newer generation of HPWs and is also ongoing. Both tests have the same three phases: laboratory testing, on-track testing under controlled conditions, and revenue service testing. Laboratory testing consisted of mechanical testing such as tensile properties, hardness, fracture toughness. Metallurgical testing such as microcleanliness and microstructural evaluation was also conducted on each material. On-track testing under controlled conditions was also performed at MxV Rail's test loops. The final phase for both tests was revenue service testing on a US railroad. AAR Class C wheels were also monitored for comparison. The HPW1 revenue service wheels were installed under coal cars; because of the downturn in coal traffic, these wheels have gained little mileage recently, but have gained an average of nearly 350,000 miles. The three best performing HPW types have fewer combined failures than the AAR Class C wheels. HPW2 wheels, as well as 44 sets of AAR Class C wheels were installed under grain cars. These have travelled an average of more than 250,000 miles, but no failures have been reported.