Staying on Track

PITTSBURGH (Feb. 7, 2020) — Temperature is an important factor when engineering for the outdoors because materials can change with the weather. Modern railways, the kinds used for high-speed trains, are made of continuous welded rails (CWRs) that are pre-expanded when set so they won’t buckle in the warm weather or crack in the cold. Ensuring the rails remain this way is vital for the safety of trains and longevity of the tracks, but the rails can change with wear, meaning the temperature at which the rail is neither contracting or expanding can fluctuate over time.

To help address this issue, researchers at the University of Pittsburgh’s Swanson School of Engineering have developed a nondestructive evaluation method to measure stress in rails, with the eventual aim of calculating when the ambient temperature will be problematic. 

“When the temperature outside is hotter or colder than usual, trains slow down as a precautionary measure to prevent excess strain on the rails,” explains Piervincenzo Rizzo, PhD, professor of civil and environmental engineering at Pitt and senior author on the paper. “Unnecessary slowdowns create train delays and interruptions in the supply chain, which is why real-time monitoring of the stress on the rails would be so beneficial to the industry.”

Rizzo and co-author Amir Nasrollahi, PhD, published their work in the American Society of Mechanical Engineers (ASME) Journal of Nondestructive Evaluation, Diagnostics and Prognostics of Engineering Systems. The ASME selected Rizzo’s paper as one of the top three papers in the 2019 Best Paper competition; it will be recognized at the 47^th Annual Review of Progress in Quantitative Nondestructive Evaluation, held in July 2020 in Minneapolis.

The paper, “Numerical Analysis and Experimental Validation of a Nondestructive Evaluation Method to Measure Stress in Rails,” (doi: 10.1115/1.4043949) was authored by Rizzo and Amir Nasrollahi, PhD, who previously was a PhD candidate and then post-doctoral researcher in Rizzo’s Laboratory for Nondestructive Evaluation and Structural Health Monitoring Studies at Pitt. Nasrollahi is currently a post-doctoral researcher at the Stanford University.

Author: Maggie Pavlick