By Bob Tuzik • May 26, 2005
The Federal Railroad Administration’s Office of Research and Development is not the best known R&D organization in the industry, but it is one of the most important. It’s work figures prominently in rulemaking and the regulatory process for the industry. That role is significant in and of itself. But FRA’s Office of R&D also actively contributes to and, in a very real sense, drives the industry’s efforts to understand and improve vehicle/track interaction on U.S. railways.
Interface Journal Editor Bob Tuzik spoke with the Dr. Magdy El-Sibaie, Chief of FRA’s Track and Rail Infrastructure Research Division, about FRA initiatives in the area of wheel/rail interaction on rail freight, commuter and Amtrak’s high-speed passenger lines.
Interface Journal (IJ): FRA’s R&D group has shown strong interest in wheel/rail interaction initiatives. What’s the basis for it?
El-Sibaie: FRA’s mandate is to assure safety on freight and passenger railways. Beyond regulating the industry for safety, we also promote to the degree possible best practices and industry guidelines.
IJ: When you say promote, do you mean initiate?
El-Sibaie: Initiate if necessary, but mostly promote when we recognize an industry practice that can be improved or better utilized. We work in partnership with the technical side of the industry to determine when an improved practice is needed, and we provide analytical support to various rule making activities by which engineering consensus is sought.
IJ: For example.
El-Sibaie: Let’s look at wheel and rail profiles. Currently, FRA does not have safety standards that explicitly address wheel and rail profiles. The closest thing we have is in the high-speed rules in the area that addresses the risk of wheel climb. We know that flange angle is an important parameter in the wheel climb mechanism, but we haven’t set a minimum requirement for flange angle. That’s left up to the industry. But we take flange angle into account when analyzing the derailment quotient – the lateral to vertical load ratio – in the qualification of specific vehicles and equipment.
IJ: With that, are you moving toward establishing a minimum angle?
El-Sibaie: That is not for me to decide, but we are helping the industry from an R&D perspective better understand the role that flange angle plays in preventing or promoting wheel climb, and its role in the bigger picture of wheel/rail interaction. This includes the type and extent of contact between wheels and rails and the friction levels present in the contact interface. A wheelsets’ angle of attack can also affect the level of derailment quotient above which wheel climb may occur. FRA R&D is working with the freight and passenger sides of the industry through the AAR [Association of American Railroads], APTA [American Public Transit Association] and other organizations to improve our understanding of these parameters and improve performance and safety.
On the passenger side of the industry, the flange angle issue came out of ongoing discussions within RSAC (Railway Safety Advisory Committee), which FRA formed to revise and update our high-speed standards. In these early discussions, it was agreed that three issues, flange angle, wheel conicity and truck equalization, would be best if first addressed by the industry, rather than through FRA rules. So APTA was given the task of looking at these three issues. FRA will decide after APTA makes its report whether it’s appropriate to address these issues through a rule or a recommended practice.
Understand that I am only speaking for the R&D side of FRA, which supports and advises the Office of Safety on technical matters. We serve as internal advisors to the Office of Safety to determine the soundness of certain rule making proposals. We also look at applications from railroads to modify standards or to issue a waiver from a specific standard. We also work directly with the industry to advance the understanding of derailment mechanisms and the techniques that we can use to improve the safe operation of wheel and rail systems.
IJ: What’s the size of the FRA R&D Department?
El-Sibaie: The R&D group is divided into two sections. The infrastructure section that I am in charge of deals with track, vehicle/track interaction, signals and train control, and grade crossings. The other R&D section, headed by Ms. Claire Orth, deals with equipment, operating practices, hazardous materials, human factors, and occupant protection issues. The nine program managers under my direction in the infrastructure group tend to specialize in specific areas of research. We also work very closely with another 10 to 12 more technically focused experts at the Volpe Center, a sister agency of the Department of Transportation, which we count on to compliment our group.
We also do cooperative work with the AAR, through their TTCI [Transportation Technology Center Inc.] subsidiary, and directly with railroads when appropriate. We also work closely with independent consulting firms and private manufacturing companies. In fact, the bulk of the FRA’s $25-million R&D budget is allocated to programs and projects done by organizations outside of the federal government, under our direction.
IJ: Give an example of how R&D works directly with a freight railway.
El-Sibaie: We are working right now on a hi-rail based optical system that takes high-resolution images of joint bars. A laser sensor detects the presence of a joint bar then arms the camera to take high-resolution images of the field and gauge sides of the joint bars on both rails. We want to know if cracks are visible in the high-resolution image, and if the system can be used to automate and increase the speed of visual inspection. Union Pacific and CP Rail have already helped us during testing of a prototype, and a final system is now ready for full-blown field-testing planned first on Union Pacific tracks.
Another example is a project that we are currently funding through a grant to the University of Nebraska to develop a system that can measure variations in vertical stiffness of the track from a moving rail car on which the system is mounted. The prototype was promising and both UP and BNSF assisted in its testing.
IJ: In a case like this, you also need to get a supplier involved.
El-Sibaie: In the case of the University of Nebraska grant, the university decides which suppliers to work with. In other cases, we will select a supplier with the appropriate technical resources. We also retain consultants to assist us, depending on whether it’s the development of a product or the execution of a task. But aside from congressional earmarks, the bulk of our funding is appropriated through a government procurement process that ensures that awards are fair and competitive.
IJ: How do you, as the head of rail infrastructure R&D, determine what’s important today, and what the FRA and the industry should be looking at down stream?
El-Sibaie: We rely on a number of inputs to determine what is needed. One of the main sources is the industry safety record. There are regulatory requirements for the industry to report derailments and accidents to our Office of Safety. This data is analyzed on frequent basis to establish various statistics and safety trends. We look at the number of accidents in a given year and organize the data based on the various accident categories and causes. In order to better gauge the impact of each category, we also determine the harm associated with each accident cause. Harm is a measure of cost in terms of fatalities, injuries, evacuations, environmental and property, damage, as well as equipment and infrastructure damage. So we have a good sense of what the safety picture looks like. For example, we know that roughly one third of all accidents over the past several years are track related. Another third are due to human factors. We know that the leading cause of all derailments is wide gauge. We know that the second leading cause is a specific human error- improperly lined switches. The program managers in my group are intimately familiar with the safety record. We study it further to better understand the detailed causes and their associated costs. We use this information to guide our research. Knowing the size of the problem is key to prioritizing the various research tasks.
My staff and I are also very active in relevant industry committees. We participate on the AAR Engineering Research, Vehicle/Track Interaction, and Heavy Axle Load committees. We also sit on the appropriate Mechanical committees and participate in various APTA technical committees. We participate in industry meetings and maintain contact with individuals on various railroads.
The RSAC group also provides us with input and guidance. We also have a number of Office of Safety specialists in the eight FRA regions who are the eyes and ears of the agency in the field. They encounter all sorts of issues and they communicate to us what is needed. We also rely on the expertise, experience and judgement of our program managers.
IJ: There has been a lot of discussion about performance-based standards in recent years. Are performance-based standards likely to make their way into the rule-making process?
El-Sibaie: If by performance-based you mean engineering standards that are based on measurable parameters, such as the Gauge Restraint Measurement System [GRMS], which applies a non-destructive lateral load to detect weak spots in the track that visual inspection may not detect, the answer is yes.
A substantial part of the R&D effort is to guide standards and rules- not just FRA standards and rules, but the industry’s internal standards and rules, as well- so that they are more performance-driven. The GRMS work is that. The work we do with track geometry and track quality index is that. The work we do in the wheel/rail interface area is exactly that. Most if not all of what we do is really directed toward driving the standards toward performance-based measurements.
IJ: What’s been the FRA’s involvement in initiatives to improve high-speed performance on Amtrak’s Northeast Corridor?
El-Sibaie: From an R&D perspective, the work that has been done in support of high-speed operation has been quite remarkable.
Back in 1996, the Office of Safety initiated a collaborative process in order to establish comprehensive rules (CFR 213 subpart G) to support high-speed operation on the Northeast Corridor. Establishing the track rules required us to study vehicle/track interaction issues. Condensing the technical work into a rule that was meaningful and sensible without being cumbersome presented a few unique challenges. But we established limits for safe interaction between track and vehicles, and parameters by which equipment can be qualified for high-speed service. I’m very proud of the high-speed rule that we issued in 1998. It has ensured that high-speed service can be operated safely on the NEC, and helped us identify a number of issues that we had not previously considered.
IJ: Such as?
El-Sibaie: We have established a limitation, for example, on the amount of net lateral load that each axle on a train can impart into the track. This net axle load ratio controls track misalignment, which we’ve identified as a potential failure or derailment mechanism in high-speed operation. There is a limit to how much lateral load each axle can transmit into the track without generating misalignment. This phenomenon wasn’t as fully understood when we first began working on the high-speed regulations. We had to understand it, and then learn how to ensure that we didn’t exceed it when we ran high-speed trains. We translated the effect into a number, indicating that the net axle load ratio cannot exceed 0.5, which means that no more than 50% of the weight of the train can be imparted laterally into the track.
It was a fruitful and rewarding process for all involved, because we ended up providing a framework for the first set of comprehensive track and vehicle/track interaction standards to permit high-speed rail in the country.
We also looked at how track geometry is prescribed and determined for various classes of track. Limiting the mid-chord offset of a 62-foot chord is the typical control exercised on track geometry over conventional tracks. But when we got into high-speed tracks, we recognized that one chord is insufficient to cover the range of wavelength anomalies that can occur. While very long wavelengths don’t impact trains operating at speeds up to 80 miles per hour, they play a significant role at speeds greater than 120 miles per hour. Very short wave length anomalies are also important in high-speed operation because they affect the different forces between two axles within the same bogie. We realized that reliance on only a 62-foot mid-chord offset was insufficient for high-speed safety, and introduced 31- and 124-foot mid-chord offsets in addition to the 62-foot mid-chord offset. So Subpart G, the high-speed rule, indicates limits controlling the offsets in the middle of three different chords – 31, 62 and 124 feet.
Moving from the safety and regulatory side to the more R&D side, we started working with Amtrak beginning in 2002 to optimize wheel/rail conditions on the Northeast Corridor. We looked into three primary areas: Wheel profiles and wheel conditions; rail profiles and grinding practices; and lubrication and friction modification.
As a result of this collaborative effort, we developed slightly modified wheel and rail profiles that will provide more optimal performance. While many recommendations on the track side have been implemented, tests on wheel profile, unfortunately, have been temporarily suspended because of the issues that were discovered with the brake system on Acela, which Amtrak and FRA are jointly working to resolve. We also performed a detailed study of the lubrication practices and conditions on the NEC, and recommended changes to lubrication practices on selected portions of the corridor where we can improve conditions. Amtrak has been an active partner with us in this process all along the way. It has been an important process of demonstrating how R&D results can be put to good and immediate use.
IJ: What’s the next crucial aspect of wheel/rail interaction on the horizon?
El-Sibaie: While there are common issues between freight and passenger, some issues are unique. In passenger railroading, for example, wheel/rail optimization has not been effectively pursued. There is real potential for extending the life of wheels and rails, and improving performance and ride quality. Many commuter railroads through APTA have begun to undertake a technical investigation of the merits of optimized wheel profiles. Wheel profiles in use today are generally safe and technically sound, but may not be optimal. We applaud APTA’s efforts to look into these issues. It’s exactly what needs to be done at this point in time.
Lubrication/friction modification is evolving. There are exciting things happening in the area of top-of-rail friction control. Vehicle based systems are evolving and we are seeing very effective wayside top-of-rail applications. The future of this technology looks bright.
There are also opportunities relating to improvements in suspension and bogie design. Operating at higher cant deficiency can allow trains to negotiate curves at higher speeds. Active suspension systems, such as tilt designs, for passenger service also warrant further investigation.
Remote monitoring of vehicle/track performance that can be married to GPS data to provide cost-effective mapping of wheel/rail conditions and vehicle/track performance shows tremendous potential. This applies to both freight and passenger operations.
On the freight side, we’re looking at ways to reduce the state of stress. Equipment monitoring, detecting areas that produce high stresses, identifying trucks that produce high lateral and vertical forces through the use of way side detectors- these all hold a great deal of promise. Implementation has already begun, but I see wider, more robust, more seamless, and perhaps more intelligent implementation being the challenge for the future.