Implementing Wheel/Rail Measurement and Analysis Technology
By Bob Tuzik • July, 2008
Any examination of the systems in use to measure and monitor wheel/rail interaction requires a discussion of the challenges associated with implementing new and emerging technology. Several industry practitioners participated in such a discussion at Advanced Rail Management and Progressive Railroading magazine’s Wheel/Rail Interaction ’08, the 14th annual seminar devoted to examining research and development efforts on freight and passenger systems.
The emergence of heavy axle loads and higher overall freight volumes in North America have had profound effects on research into wheel/rail interaction and the overall stress state of infrastructure and rolling stock, said Mike Franke, Amtrak’s Assistant Vice President – State and Commuter Partnerships. “They have significantly changed the way we manage and organize track maintenance activities and they have leveraged technology as never before in day-to-day condition monitoring of equipment and track.”
There is a great deal of interest from around the world in what we’re doing in the way of wayside measurement and fault-detection, and how the information it generates can improve safety and the reliability of the rail network, he said.
Technology Drivers
The drivers for new technology include improvements in service, safety, productivity, fuel efficiency, asset utilization and revenue growth, said Robert Blank, Norfolk Southern’s Director of Research & Tests. The technology needed to help achieve these goals is identified by various means at NS. Service metrics identify why trains are delayed or what incidents took place; incident reports identify rail and wheel failures. “We also look at where we’re spending maintenance dollars, and how we’re meeting safety and service expectations,” Blank said.
NS is implementing ECP (electronically controlled pneumatic) braking technology on its coal car fleet, for example, to improve performance and reduce overall costs.
As part of its research effort, NS looks at work being done by other railroads. It also works with industry associations, such as the AAR and its TTCI and university affiliations, to identify technologies that can be applied to railroad-related issues. NS also works closely with suppliers. “They are where a lot of the new technology comes from,” Blank said.
The NS R&T Department also works with internal stake-holders of new technology to identify the appropriate sites, infrastructure requirements (power, communications, access, etc.) and the service lanes that may be affected. “If we’re going to be stopping trains for high-impact wheels, for example, we want to know what effect it’s going to have on overall operations and service commitments,” Blank said. NS also determines which departments’ budgets will be affected and which department will be responsible for maintenance. Costs and benefits must be identified in order to compete among hundreds of other projects for funding. Where tangible benefits cannot be identified but a compelling case can be made to introduce a new technology, the finance group will sometimes give the go-ahead for “research,” he said.
Once a project is approved, implementation typically requires extensive communication between R&T, Maintenance, Communications and Signals, Mechanical, Transportation and the IT Departments. “Our IT people want to ensure that the data and data transmission are secure.”
Post-deployment, NS maintains on-going effort to quantify the benefits of the technology and to address the root causes of the problems that it identifies. “The work that the Wheel Defect Prevention Research Consortium is doing to determine the root causes of high-impact wheels and what can be done to reduce them has come from this,” he said. Through the Advanced Technology Safety Initiative (ATSI), NS, along with BNSF and other Class I railways, is working to reconcile issues relating to cost/benefit issues between railroads and private car owners.
Finding the “Win-Win”
“We are trying to use technology — especially with ATSI — to find that ‘win-win’ between the railroads and the private car fleet,” said Lisa Stabler, BNSF’s Assistant Vice President for Quality and Reliability Engineering.
Railroads are focusing on situations in which they can provide information that car owners can use to perform maintenance that will enable the car to make it to its next maintenance cycle. Instead of dealing with the “lose-lose” of who is going to fix the WILD-identified wheel, railroads and car owners are looking for the “win-win” associated with identifying wheels that the WILD network has predicted will generate high-impact loadings in the near future, and replacing them while the car is in the shop for scheduled maintenance.
BNSF began implementing various wayside technologies in part to reduce the number of mechanical-caused derailments. One derailment that occurred in 2000 played a significant role in the development of BNSF’s widespread wayside detection systems. This low rail rollover derailment was important because it occurred 241 miles beyond an experimental truck-performance detector (TPD) that the train had recently passed. Data from the TPD showed higher L/V forces at the end of the train, where the derailment began. We asked ourselves, Stabler said, if we could have prevented this derailment if the TPD had been in a production rather than a research environment.
Along the way to answering that question, BNSF’s wayside detector network has grown from its initial network of six stand-alone detectors, using two different technologies, to 72 stand-alone detectors, using 12 different technologies. (BNSF also employs a network of 763 warm-bearing detectors.)
Still, competing for resources to establish and expand effective wayside measurement and monitoring programs is an ongoing challenge. Showing management some of the data or pictures identified by detector systems that otherwise would have caused a derailment or service interruption is a good way to get management’s support, Stabler said. One you obtain that support, she said, “you’d better be able to show results.”
That’s why BNSF and the Six Sigma group, which Stabler leads, focus on “validation and quantification” when selecting detector systems. The first thing we do after procuring a detector is determine that it can demonstrate an acceptable R&R (repeatable and reproducible) gauge, Stabler said. After we’ve demonstrated that it’s repeatable and reproducible, we make sure that that it actually does what it’s supposed to do. Before we call it “good,” the car inspector — the person who’s going to bad-order the car — has to agree that the detector works. “Field concurrence is critical,” she said.
Dataflow is another critical aspect of wayside detection technology in that railways have begun making decisions about whether a car that is flagged for maintenance must be set out immediately or if it can be bad-ordered and sent to the next mechanical repair facility. This, along with the associated repair work and billing, become part of the car-repair history system.
In the end, it all comes down to dollars. “While we never put a price on safety, we understand that there is a cost associated with derailments,” Stabler said. “We’re all about showing that the money spent on wayside detector technology is generating a return and that we’re spending BNSF’s money wisely.”
Clearing the Hurdles
Ryan McWilliams, Vice President – Technology & Business Development, at Salient Systems, Inc., looked at the hurdles to implementing wayside measurement and performance-monitoring technology from the suppliers’ perspective.
Wheel Impact Load Detector (WILD) technology, which was developed to identify high-impact wheel loads that were causing track damage, was the first wayside technology adopted as an industry standard, McWilliams said. The first commercial WILD systems were installed in 1985. Significant implementation began in 1993 with the widespread implementation of AEI tags, which are key to monitoring the performance of individual cars. By 1995, there was enough confidence in the systems for the AAR to implement an interchange rule allowing their use. Beginning in 2005, hand-gauge measurements were no longer required for verification.
Today, there are more than 200 WILD systems on six continents; more than 100 of them are in North America. Development, acceptance and implementation was a slow process, however, requiring 20 years for the industry to gain confidence in the system. While the end result is good, McWilliams said, 20-year product development cycles can be prohibitively expensive. Fortunately, he said, suppliers have found ways to develop partnerships with individual railroads and the industry, overall.
The next technological and implementation frontiers include longitudinal rail stress monitoring, which monitors the rail neutral temperature to warn of impeding buckling hazards and to alert railway maintenance departments when to apply a slow order. Suppliers have had to wait for enabling technologies, such as battery optimization, better communications links, and wireless transmission, in order to produce a system with costs that were low enough for railroads to actually implement and use. “We’re now able to produce a rail-mounted module that would have been technologically impossible 10 years ago,” McWilliams said.
Identification and measurement of difficult-to-detect subsurface cracks in wheels and axles and other components represents the next frontier. Salient Systems and other suppliers are investigating the use of X-ray, ultrasonic and other technologies to identify an efficient, cost-effective way to detect sub-surface cracks in critical components.
The session moderator, Amtrak’s Mike Franke, pointed out that despite the needs that have been identified and the benefits that have been shown, the railway industry’s expenditure for research on new technology continues to be among the lowest of any developed industry.
“We do have an industry research effort through the AAR and FRA that helps supplement what individual railroads contribute to research,” NS’s Bob Blank said. While it’s a struggle to increase research spending, due in part to the capital-intensive nature of the industry, research budgets have been increasing in recent years, he said.
While agreeing with Blank and the other panelists assessments, BNSF’s Lisa Stabler, a self-characterized “outsider” who came from the automotive industry, said that the railroad industry does itself a disservice by thinking that it doesn’t move quickly. “I have seen more change in this industry in the past eight years than I saw in 20 years in the automotive industry. It’s amazing how quickly this industry can move,” she said. “It’s an exciting time — a golden age for detector technology.”
