Los Alamos Engineers Workin' On The Railroad

The research is tied to the largest Department of Energy railroad project ever conducted. DOE's Fernald Environmental Management Project in Ohio is scheduled to ship hundreds of tons of treated waste by rail to a disposal site in Utah.

The AAR awarded Los Alamos $150,000 to begin the research. DOE Fernald matched the research grant.

"If new alloys we help develop are accepted by the industry, it will affect rail wheels worldwide," said Dan Thoma, leader of the Laboratory's alloy development program. "Even a modest change in the life of the product can mean a savings of millions of dollars."

"Los Alamos' unique equipment and metallurgical staff were the basis of the formation of this partnership," said Dan Stone of the AAR Transportation Technology Center. "And the Laboratory's relative proximity to the TTC's Pueblo, Colo., location helps ease problems with research planning, coordination and execution."

When train wheels skid during braking, the tread of the wheels can reach temperatures over 1,600 degrees Fahrenheit. As soon as the train stops, the wheels cool quickly, causing a thin layer of steel to transform into a brittle, untempered form called martensite. The martensite causes shallow, widening cracks on the wheels, or spalling. Eventually, the wheel goes out of round and wrecks the surface of the tracks. The damage may lead to derailments.

Because of spalling, the railroad industry must replace 75,000 wheels each year, at an annual cost of $70 million. These wheel defects also increase rolling resistance which increases locomotive fuel consumption. The industry estimates fuel costs rise about $50 per defective wheel, which means millions spent in total per year on extra fuel.

Los Alamos will investigate alternative alloys that limit the formation of martensite or cause the steel to return to its crack-resistant form during rapid cooling. Researchers will investigate combinations of alloying materials, including chromium, silicon and cobalt.

Although the railroad industry conducts large-scale research, Los Alamos' technical capabilities in metallurgy will allow rapid analysis and development of candidate alloys.

"We have a complementary set of tools to do this research," said Thoma. One such tool is a device that can simulate the temperature changes and pressures that railroad steel goes through during braking. A "quench deformation dilatometer" can cool a sample 1,800 degrees per second and apply simulated loads, allowing Thoma to evaluate the thermal history of steel samples.

"Even though it's been studied for years, steel is still an interesting material for research," said Thoma. "And alloy development is tied to the Laboratory's core mission, supporting maintenance and stewardship of the nation's nuclear weapons stockpile."

Fernald contributed to support the research as an investment toward its massive environmental cleanup effort. For decades, Fernald refined raw uranium into metal used in production reactors at other Department of Energy sites to make plutonium and tritium for nuclear weapons. Now 473,000 cubic yards of waste pit materials and surrounding soils will be treated by a thermal-drying process. Then the treated waste will be loaded onto gondola rail cars for disposal at a licensed site in Utah. The cleanup will require shipping about 100 ore cars loaded with contaminated soil every 11 days for seven years.

Los Alamos National Laboratory is operated by the University of California for the U.S. Department of Energy.

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