Interface - The Journal of Wheel/Rail Interaction

WRI '08 SEMINAR OVERVIEW

Wheel/Rail Interaction ’08: Data to Information - part 2 of 2 (continued)

Top-of-Rail Friction Control
Railroads have long used gauge-face lubrication as a means to extend rail life. More recently, they’ve introduced innovative TOR friction modifiers to supplement gauge-face lubrication and further reduce wear associated with lateral forces. But rail life extension is not the only benefit to be reaped through implementation of TOR friction control.

To better understand, and better quantify the benefits of TOR friction control, the Transportation Technology Center, Inc., (TTCI) conducted a two-year survey of TOR friction control application systems (both wayside-based and mobile systems) at a number of field sites. The survey confirmed the benefits of TOR friction control systems and reiterated some of the limitations, as well.

Curving forces and rail wear both showed significant reductions under TOR friction control. Energy consumption was also reduced. Results also indicate that TOR friction control has no negative impact on braking or wheel wear. The effectiveness of wayside and mobile application of TOR friction modifiers was reduced, however, under heavy braking, indicating that route characteristics must be carefully considered.

Understanding the benefits and limitations of TOR lubrication is an important step in the right direction, said Richard Reiff, TTCI Principal Investigator. The next step is further study of application strategies in order to fully exploit the benefits and minimize the limitations. There is potential to further optimize applicator output rates and spacing on wayside systems, and applicator deployment strategies on mobile-based systems.

Automated Track Inspection
The Federal Railroad Administration (FRA) Automated Track Inspection Program (ATIP) has been collecting track geometry, ride quality and other track data on the U.S. rail network since 1974. The ATIP program employs several geometry cars and the Track Data Management System (TDMS), which was designed to streamline track data manipulation, data viewing, record keeping and route scheduling.

In light of recent rail rollover derailments citing rail seat abrasion of concrete crossties as a contributing factor, these technologies have recently been brought to bear on rail cant problems related to concrete ties, said Arthur Clouse, Program Manager, Automated Track Inspection Program, in the FRA’s Office of Safety, Assurance, and Compliance. The FRA established a Rail Seat Deterioration Task Force to determine the derailment circumstances, develop a better understanding of rail seat deterioration and failure, and to provide recommendations to the Rail Safety Advisory Committee (RSAC).

In conjunction with FRA investigations, Volpe National Transportation System Center conducted numerical simulations and analytical studies to illuminate the role of track geometry, and resulting forces, in the development of rail seat abrasion. Analysis of the track geometry data from the derailment sites indicated that combinations of profile and alignment irregularities contributed to the derailments, and that these irregularities were within FRA Class 3 geometry limits. Based on simulations, the present irregularities produced powerful dynamic responses and increased crosstie loads beyond acceptable limits.

To better understand the factors associated with types of derailments, ATIP conducted geometry surveys with the FRA’s DOTX 216 geometry vehicle. Data from the surveys was used to develop techniques to identify problematic sites.

Surveys measuring rail cant on a foot-by-foot basis allowed ATIP to develop and test “alarm” and “alert” cant thresholds. Follow-up inspections on concrete crossties identified as problematic during surveys confirmed that rail cant measurements are effective in identifying locations of concern, Clouse said. The FRA is also working on methods to identify other indicators of failed concrete crosstie systems, such as base gauge, relative rail roll, and gauge widening.

The RSAC Concrete Crosstie Task Force continues to assess the issues and is expected to provide recommendations and measurement parameters that will help identify concrete crosstie deterioration.

Condition Monitoring
Frequent inspection and monitoring of infrastructure and rolling stock has become a vital part of day-to-day railway operations. As railroads and car owners have sought to expand their inspection regimes, technology has kept pace — and the number of inspection/monitoring tools and systems continues to grow.

The “you can't manage what you can't measure,” adage holds true, said Ryan McWilliams, Vice President of Technology and Business Development at Salient Systems Inc. But as the array of inspection tools grows, it's important for industry leaders to know the strengths and limits of the available options.

The essential purpose of Condition Monitoring is to monitor the health of rolling stock and rail. wayside and rail-mounted detectors present the most efficient and cost effective method of doing so, McWilliams said. To maximize the effectiveness of data collected through such means, systems must be in place to process the data in real time and generate clear information that railroads can act on. Since different tools measure different aspects of railroad operations, a combination of tools is often necessary to monitor the health of a railroad.

Truck Performance Detectors (TPDs) measure a critical aspect of vehicle dynamics by identifying skewed or hunting trucks. These detectors are able to associate measurements with individual wheels, axles and trucks and forward results — and alarms, where appropriate — to wheel data management systems.

TPDs measure interactions at the wheel/rail interface to evaluate vehicle performance and identify irregularities. These systems are able to associate symptoms with causes to ensure that the right kind of maintenance is performed. Gauge spreading, wheel unloading, truck warp flange climb, track panel shift and rail rollover, for example, are all typical of very different root problems, McWilliams said. TPD evaluations help eliminate the guesswork from correcting these issues.

“The right monitoring tools ensure that maintenance dollars are spent when and where they're needed most,” McWilliams said. “Decision-makers must be attuned to which technologies best fit their condition monitoring needs.”

Jeff Tuzik is Editorial Assistant, Interface Journal

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