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December 2011
by Walter Weart
When it comes to detecting rail flaws or identifying worn-out components, track inspection equipment and services are top of mind for railroad maintenance-of-way managers.
Railroads use hi-rail vehicles, electronic detection equipment, handheld devices and other means to inspect rail and tie conditions, identify rail defects or determine gauge strength. To ensure their offerings meet today's track inspection needs, equipment suppliers and service providers continue to develop ways to make detection methods faster and more accurate.
Railroads seek increased testing speeds, real-time data processing, rail profiling and imaging, and continuous testing capabilities, said Jill Shafer, sales and account manager for Nordco Rail Services & Inspection Technologies.
They also want more technological advances to better automate track inspection and better understand the condition of their assets, adds Bob Madderom, vice president and general manager of Holland L.P.'s railway measurement systems and services division.
"Whether it is crossties, rail [or] switch materials, accurate condition assessment can help with replacement planning, quality assurance and, potentially, improvement of overall safety and economic performance," he said.
Progressive Railroading conducted phone interviews and exchanged emails with eight track inspection equipment suppliers and service providers to determine how they're employing technology to address railroads' needs. Their responses follow.
Since 2009, ENSCO Inc. has focused on four primary technology advancements. The first: enhancing RailScan Lite, a hi-rail-based inspection platform initially released in fiscal-year 2008 that was updated in January to include cross-level, warp and twist measurements. The non-contact system provides measurements of the parameters and relays the data to an in-cab laptop up to a hi-rail vehicle's maximum speed, said ENSCO Director of Commercial Rail Operations Jeff Stevens in an email.
The second major focus concerns unmanned or autonomous measuring systems. ENSCO has deployed more than 250 autonomous Vehicle/Track Interaction (V/TI) Monitors, which are inspecting more than 40,000 miles of track per day, said Stevens. Installed on both locomotives and passenger cars rather than dedicated vehicles, the monitors are used by Class I, passenger and commuter railroads.
Over the past two years, ENSCO has added a new measurement parameter to the V/TI device to provide short chord track geometry surface measurements, as well as new data mining techniques to evaluate repeated, lower-level readings that can indicate high levels of track stress and risk, said Stevens.
ENSCO is working jointly with the Federal Railroad Administration's (FRA) Office of Research to develop the Autonomous Track Geometry Measurement System (ATGMS). Currently, one ATGMS system is operating in the United States under FRA evaluation.
"The major improvement is the ability to conduct geometry inspections in an autonomous environment," said Stevens.
Another focus is a next-generation Digital Track Notebook®, a mobile web- and field-based application that's designed to help track inspectors comply with the FRA's and Transport Canada's inspection standards. Introduced in January, the notebook can determine when track inspections are due based on regulatory requirements, collect maintenance or safety defect information and manage remedial actions. The notebook is offered as a subscription-based, paperless track inspection management service.
ENSCO also has extended its "machine vision" capabilities from inspection of rail joints for cracks to inspection of the track roadbed, with a focus on tie evaluation, said Stevens. High-resolution cameras capture images of the roadbed and a combination of automated algorithms and office data processing determine individual tie ratings. The company added that technology to a new Comprehensive Track Inspection Vehicle (CTIV), which will enter the testing phase by year's end, said Stevens. The CTIV also features track geometry, rail profile, third-rail measurements, joint bar inspection and a right-of-way video collection platform.
Georgetown Rail Equipment Co. (GREX) offers the Aurora™ Track Inspection System, which provides railroads state-of-the-art functionality in machine vision tie inspection for both wood and concrete ties, said GREX Director of Aurora Integration David Hunsucker in an email.
Data is collected using a hi-rail vehicle traveling at speeds up to 42 mph. The system determines indications of rail seat abrasion on concrete ties and provides four grades on wood ties based on customer thresholds, said Hunsucker, adding that Aurora can provide accurate GPS locations for switches, crossings and each inspected tie.
The system offers customized component inventory, rail base corrosion indications, and electronic reporting for customers to review and perform an in-depth analysis.
Since its inception in 2005, Aurora has been used to inspect more than 40 million crossties in North America, said Hunsucker, adding that the system continues to be enhanced to improve its capabilities. Last year, GREX boosted Aurora's data-collection speed and enhanced its collection system, among other upgrades.
"These improvements include enhanced algorithms to capture and measure 25 various tie assessment metrics," said Hunsucker.
This year, the company improved the near-real-time processing of data collected for indications of rail seat abrasion.
Currently, GREX continues to develop an Aurora solution to address the new FRA rule covering automated concrete-tie inspection. The solution combines Aurora's rail seat abrasion and pad-wear detection with a near-real-time, 24-hour turnaround, said Hunsucker.
The company is developing a method to identify missing or broken fasteners on concrete ties. The first phase of software development was implemented in July and a second phase is scheduled for completion by year's end. The method should be released for production in second-quarter 2012, said Hunsucker.
Over the past two years, Holland L.P. has added some machine vision systems to its TrackSTAR® track testing vehicles. The company aims to provide automated inspection and classification of wood and concrete ties, and align the classification with the performance-based measurement Gauge Widening Projection from TrackSTAR's load-axle Gauge Restraint Measurement Systems, said Bob Madderom, VP and GM of Holland's railway measurement systems and services division.
Many railroad and transit system customers have expressed interest in automating tie inspection, he said. TrackSTAR-equipped vehicles now are measuring rail cant over every foot of track captured within most optical rail profile measurement systems, said Madderom. Recently, rail cant has become a more important measurement from the perspective of rail seat deterioration on concrete ties, or where differential plate cutting is occurring on wood ties, he said.
Variation from design cant is measured and can be reported as exception-based on railroad thresholds to identify very short track segments that require maintenance. Cant exceptions now can be reported in real time along with normal geometry or track gauge strength exceptions from TrackSTAR, said Madderom.
Automated inspection systems also can be used to assess many other track conditions, such as rail surface condition, joint bar, fastener count and condition. The primary challenge for the systems: the size of the data files that are collected by the testing vehicles and the development of software that can deliver accurate condition assessment, said Madderom.
Loram Maintenance of Way Inc. offers customized track inspection services designed to address each railroad's unique circumstances.
"We work with our customers to create customized track inspection programs that address their own unique challenges in a cost-effective way," said Loram Vice President of Asset Management Darwin Isdahl in an email.
Loram uses a combination of different technologies to achieve the goal. The company's hi-rail Rail Inspection Vehicle (RIV) is used by Class Is and transit railroads in North America. The RIV is equipped with a two-camera optical transverse profile measurement system designed to measure the profile of both rails in real time, and collect data to support rail grinding quality control. The RIV also is equipped with a high-resolution image acquisition system used to collect and display blur-free images of the railhead. The system details pitting and surface cracking on the top-of-rail surface.
Loram's proprietary software displays data for analyzing and reporting. The collected data is used to develop a precise grind plan for a rail grinding program and create rail wear data reports, quality reports and several other reports that detail track parameters, such as track gauge and rail cant.
"With the number of RIVs we have out there now, we have the ability to learn a great deal about the cause and effect of different situations, and better understand how to apply the grinders in the most effective way possible," said Isdahl. "If we don't have a technology that we feel would be useful, we'll go get it or partner with someone who has it."
Loram's track inspection service is constantly evolving, company officials said.
"We have several technology partners we work with to ensure we are using the latest and greatest rail inspection technology out there," said Isdahl.
Depending on a railroad's needs, Loram uses several systems that address rail profile, crack detection and rail corrugation. The company also continues to add more RIVs to its fleet based on Class I and transit railroad demand. More Class Is are realizing the benefit of using full-time RIVs in conjunction with their rail grinding programs, Loram officials said.
The company also has introduced a proprietary grinding quality index/calculation that quantifies rail-head shape. Loram spent the past 10 years developing the index. The calculation is an indication of how closely a railhead profile matches the desired template. A number is assigned between 0 and 100, with 100 being completely within a railhead's specified tolerance band, to enable the grinding supervisor to make the proper decisions to achieve desired results, Loram officials said. The index can be stored, post-processed and analyzed to help customers make key planning decisions, they said.
MERMEC Inc. is working with Class Is to optimize its Unattended Geometry Measurement System (UGMS) for use on North American tracks. Currently used on passenger trains in the United Kingdom, UGMS will be deployed on freight cars to collect track geometry data during normal revenue service, according to MERMEC.
"We are also introducing products from our parent company's line into the U.S. and we are especially keen on vision system technology, which will allow users to visualize the defect area as well as supply inspection data," said MERMEC Engineering Manager Bruce Sopher during a phone interview.
One such offering: VCube, which combines video inspection with defect measurement, and is based on several systems that have been used in Europe the past few years. Introduced this year, VCube is designed to capture video images to enable users to view a complete measured track. The video image capture feature provides a photo of a complete measured track, while a rail flaw detection feature is driven by pattern recognition-based search of the video images, and defect measurement serves as a supporting function to the inspection system.
VCube can automatically detect rail, fastener and track bed defects using the pattern recognition-based video image search. In addition, the system can provide a precision defect measurement as a supporting function to an inspection system; while an inspection system estimates a defect, VCube can make more precise measurements, according to MERMEC.
"The user can check for 26 different types of defects on the rails, fasteners, ties and roadbed," said Sopher, adding that a video capture feature reduces the need for employees to walk along track.
VCube features can be separately deployed by adding processors and enabling more software detection.
Modern Track Machinery Inc. (MTM) offers a range of electronic recording systems designed to enable railroads to inspect track and locate all types of defects.
The company has developed a range of measuring instruments and offers geometry trolleys (the AMBER model), electronic rail profile, switch geometry inspection, digital track gauges, electronic straightness measurement instrument for welds, and a laser line and level tool. MTM plans to offer an entire line of handheld measuring instruments, just as the company has with small maintenance equipment, said MTM General Sales Manager Alan Reynolds in an email.
"We have added GPS to our AMBER portable track geometry recording unit to enable one operator to record cross level, travel distance and gauge," he said, adding that GPS capabilities now are available for the RECTIRAIL straightness measurement instrument.
MTM also has made its traditional RCAT track gauge device a digital product; the newest version is GARNET-DL, which enables a user to log data to a PDA for retention and analysis, said Reynolds.
Nordco Inc. has made several changes to its product line over the past two years, including one new track inspection vehicle, the NRS-195, and an enhanced one, the NRS-260.
Both utilize digital signal technology to collect test data at speeds up to 30 mph and feature an optional GPS, said Jill Shafer, sales and account manager for Nordco Rail Services & Inspection Technologies, during a phone interview.
"We have orders for both vehicles and are upgrading our service fleet, as well," she said.
Nordco also offers the XL9-11 wheel probe and tracer wheel, which was enhanced to better detect vertical railhead splits. The probe can complete work that's typically done by two probes, providing room to add another device in the future, said Shafer.
Earlier this year, Nordco introduced the Single Rail Tester, which is designed to inspect a single rail for internal defects.
"The Single Rail Tester will examine the rail with only one pass over the rail rather than two — a major time saver," said Shafer, adding that the previous version of the device required more than one pass to inspect rail.
Nordco also offers the One Pass, a type of single-rail tester that features a portable multi-channel digital ultrasonic flaw detector and the company's XL9-11 wheel probe. In addition, Nordco has developed "On Board Run on Run" technology, which is designed to enable an operator to compare current results against previous test data collected from the same track section.
An operator can view the results from the last test displayed side-by-side with current results to compare changes and conduct further evaluation, said Shafer.
Plasser American Corp. has been involved with track inspection systems for 40 years. EM-GRMS cars have been in use since the 1990s and currently are being employed by Amtrak, CSX Transportation, MTA Long Island Rail Road and the FRA.
Recently, Plasser American worked with Norfolk Southern Railway to supply and install equipment for two test vehicles built by the Class I. The two cars are built on the frames of retired locomotives.
"We supplied and installed the measuring frame, the complete inertial/navigational geometry measuring system, the rail profile measuring system, track component video monitoring system and a laser-based clearance measuring system," said Bernhard Metzger, Plasser American's track recording and research department manager, during a phone interview.
The company also supplied the complete display and analysis software. The laser clearance system can sweep 360 degrees and typically measures about 1,000 points per revolution. Plasser American offers a newer system that can scan up to 10,000 points per revolution.
For example, it's used to locate adjacent track centers and develop a complete ballast profile, said Metzger.
He believes there will be more video systems developed featuring playback synchronized with data.
"When an exception is noted, the matching video will be available, avoiding the time and expense of going back to manually inspect the track," said Metzger.
Track inspection technology developed by Vortok in Great Britain is now available in the United States through TUV - Rail Sciences Inc.
"Track engineers have known for some time that rail should be at the correct neutral or stress-free temperature to avoid track buckling or pulling apart as the surrounding ambient temperatures change seasonally," said TUV - Rail Sciences President Gary Wolf during a phone interview.
Typically, rail is laid in North America at a neutral temperature of 95 degrees F, but over time the temperature can change due to seasonal cycles and track maintenance practices, such as curve lining and tamping. In the past, the only method to test for change in neutral temperature was to cut the rail, measure the gap, manually calculate the neutral temperature change and re-weld the rail — a time-consuming process that introduces more joints in the rail, said Wolf.
For the past five years, TUV - Rail Sciences has offered the Vertical Rail Stiffness Equipment, or VERSE®, method, a non-destructive process that calls for first removing the fasteners from a section of rail about 100 feet in length with VERSE equipment positioned over the center of the rail section. The rail then is lifted to a prescribed distance. Using a transducer attached to the rail and a VERSE-supplied handheld computer, the neutral temperature is quickly determined, said Wolf.
"While the problem with neutral temperature is mainly a welded-rail concern, we have seen instances where the splice bars on jointed rails have become so ‘frozen' with rust that it acts like welded rail," he said, adding that VERSE currently is used by several Class Is and transit agencies.
TUV - Rail Sciences also offers MRail, a vertical track deflection method introduced in February that's based on eight years of research at the University of Nebraska-Lincoln. MRail can provide information on track stiffness and the "foundation" of the track that wasn't previously available, said Wolf. The data then can be used to correct sub-grade weaknesses or deficiencies.
MRail has undergone extensive testing over thousands of miles of track and has been found to be effective in locating areas of large vertical track deflection that are indicative of ballast fouled by mud or coal silt, broken ties and defective track, said Wolf.
"An advantage to the MRail system is that the equipment can be attached to a conventional rail car and used in a revenue service train to gather actual data from real train operations while not interfering with service," he said.
Walter Weart is a Denver-based free-lance writer.
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