Norfolk Southern’s safety plan seeks to refine wayside sensors
Norfolk Southern is working with Georgia Tech Research Institute to develop this inspection technology. It has previously identified 16 corridors where it will be deployed, including the tracks that run through East Palestine and Pittsburgh.
Norfolk Southern, the Atlanta-based railroad whose train derailed and caught on fire in East Palestine, Ohio, last month, released a plan Monday that it says will “immediately enhance the safety of its operations.”
The company has promised to deploy more detectors along its tracks, re-evaluate how they are used, and lean more into technological solutions for diagnosing the health of its trains.
Norfolk Southern said the steps are based on the findings outlined in the National Transportation Safety Board’s preliminary report on the derailment, which was released last month and which noted that a system of hot box detectors failed to prevent the derailment.
Federal investigators found that the eastbound train had passed three such detectors, which use infrared sensors to measure temperature and to screen for overheating in the wheel bearing, before the accident.
In the 10 miles between the first and the second detector, the sensors registered a 270% jump in temperature — but both readings were below the alarm threshold set by Norfolk Southern. The third detector, 20 miles down the track, triggered an alarm, but the warning came too late. The train derailed soon afterward.
In response, Norfolk Southern said Monday it would probably add about 200 more hot bearing detectors to its network — a 20% increase over its current installations. The estimate is based on filling in stretches of track where the distance between these detectors is more than 15 miles.
The railroad didn’t say it would immediately adjust its temperature thresholds for alarms, but instead said it would “work with the industry on a comprehensive review of standards and practices for the use of hot bearing detectors.” The review would include re-examining thresholds, analyzing patterns from the data collected from these detectors, and looking at how to respond to high temperature alarms.
Norfolk Southern also said it would pilot “multiscan” hot bearing detectors, which scan a larger portion of the wheel and bearing as a train passes, and it would add 13 new acoustic bearing detectors to the five already in the field.
Such devices monitor for vibrations coming from passing bearings and can provide a warning that a part is deteriorating long before it becomes hot enough to register with a hot box detector.
“Acoustic defect detectors, basically, are sets of microphones on the side (of the track),” said Constantine Tarawneh, director of the University Transportation Center for Railway Safety at the University of Texas Rio Grande Valley.
According to an analysis by the Federal Railroad Administration in 2019, there were 39 such detectors deployed in the U.S., mostly on the East Coast.
“They’re effective, but the chances of a bearing passing one of those are very slim,” Mr. Tarawneh said.
Mr. Tarawneh said the typical way bearings go bad starts with a spall — a thin, vertical depression in the steel.
“The steel gets fatigued. A piece of the metal chunks off. The others are grinding on it,” he said. “If you have a vibration detector, it will tell you” that something has changed.
“By the time you detect things with temperature, it’s way too late for you to react,” he said. “Now, with so much technology, so much AI, so much computing power, we should be able to do things (that are) more predictive, not reactive.”
Norfolk Southern has talked about acoustic detectors for years.
It had installed its first three such sensors by early 2014, according to a corporate sustainability report that year. In it, the railroad talked up the predictive attributes of this technology, contrasting it with hot box detectors, “which identify problem bearings only after they have started to fail.”
“In those cases, the company loses time and burns fuel unproductively in stopping trains en route to remove a railcar with a defective bearing,” the sustainability report said.
Norfolk Southern’s first three acoustic detectors were installed on main lines between West Virginia coal mines and Lamberts Point Coal Terminal in Norfolk, Va.; between Cincinnati, Ohio, and Chattanooga, Tenn.; and between Bellevue and Columbus, Ohio.
Moving inspections
The company’s newly announced safety plan also promises to accelerate its digital train inspection program, which Norfolk Southern began working on in 2020.
The concept featured prominently in Norfolk Southern’s digital strategy presentation at the company’s investor day in December, where one slide showed a rendering of a train passing under a canopy with cameras on all sides.
“Inspections are a cumbersome and time-consuming process, vulnerable to human limitations, heavy rain, fog, snow, low visibility — they all could impact it,” Mabby Amouie, assistant vice president of enterprise platforms and data, said during the presentation.
He talked about “machine vision technology,” which captures high-resolution images as a train passes through at full speed. Those images are then analyzed using artificial intelligence, to assess the health of the train.
Mr. Amouie said these digital inspections, along with other wayside technologies, benefit the company in two ways. “One, inspecting trains in motion keeps cars in motion, which our customers like. And two — and this is the revolutionary part — when a train is in motion under load … you will learn so much more about the health of a given component and see that it may be becoming stressed before it actually fails.”
The company is working with Georgia Tech Research Institute to develop this inspection technology. It has previously identified 16 corridors where it will be deployed, including the tracks that run through East Palestine and Pittsburgh.
Norfolk Southern also noted on Monday that last week it has agreed to join the Confidential Close Call Reporting System, administered by the Federal Railroad Administration. The program gives rail workers a way to report unsafe conditions and concerns.