Interface - The Journal of Wheel/Rail Interaction

WAYSIDE DETECTION SYSTEMS

Wayside Detection Systems Move to the Forefront of the Stress State Landscape
By Bob Tuzik

Wayside measuring systems increasingly are being used to monitor vehicle/track performance and to identify poorly performing vehicles or track components before they cause time and capital consuming problems. Wayside (and onboard) technology is being used as part of North American railways' mandate to reduce the stress state to plan maintenance based on performance characteristics, rather than on more traditional time- and mileage-based maintenance intervals.

"We are trying to move away from maintenance that’s preformed in a reactive manner when a component fails or breaks in service, or causes an operational disruption by forcing the train crew to stop and cut a car out of the train," Scott Cummings, senior engineer at the Transportation Technology Center, Inc., told delegates at Interface Journal and Advanced Rail Management’s 11th Annual Wheel/Rail Interaction Seminar.

While railroads and car owners agree that culling bad actor cars and high impact wheels from the fleet is a good thing, there is debate and disagreement over the 90-kip alarm levels (which were lowered to 80 kips in July) at which wheel impact load detectors (WILD) are set. There is also debate about the consistency of the readings, which can vary with speed, lading and detector location.

Detroit Edison, which owns a fleet of 6,000 aluminum coal cars, developed a proactive "50-Kip" maintenance strategy to monitor the performance and manage the maintenance of wheels on its high-mileage, heavy-haul fleet. Detroit Edison has found that wheels that read within the normal loaded range at one detector sometimes read at or beyond alarm levels at the next.

"There are such variations in the WILD readings of my wheels that I cannot always catch a wheel correctly," said Dennis Buda, Detroit Edison's supervisor of unit train operations. "I'm not an opponent of the WILD system," he said, "but WILD calibrations should be standardized to meet M1003 quality standards just like everything else in the railroad industry."

Another point of contention among private car owners is that flat or out-of-round wheels that generate high impact loads are often the result of operating practices—poor train handling or failure to release hand brakes.

While both railroads and private car owners, which represent more than 60% of the North American fleet, believe that preventive measures represent the most cost-effective approach to wheel maintenance, the issue of "Who benefits and who pays?" remains. Buda pointed out that wheel changeouts on Class 1 railroads cost Detroit Edison, alone, more than $2 million in 2004. The overall cost of removing cars from service to change out wheels was about $3.6 million over the past 12 months.

"Despite these increased costs, 97% of the economic benefit of removing high impact wheels goes to the Class 1 railroads; 3% goes to the private car owners. That's hardly balanced," Buda said.

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