Experimental and Numerical Investigations of Asymmetric Chord-reference System Regarding Track Geometry Measurement

The application of Doppler-based LIght Detection and Ranging (LIDAR) technology for determining track curvature and lateral irregularities, including alignment and gage variation, are investigated. The proposed method uses track measurements by two low-elevation, slightly tilted LIDAR sensors nominally pointed at the rail gage face on each track. The Doppler LIDAR lenses are installed with a slight forward angle to measure track speed in both longitudinal and lateral directions. The lateral speed measurements are processed for assessing the track gage and alignment variations, using a method that is based on the frequency bandwidth dissimilarities between the vehicle speed and track geometry irregularity. Using the results from an extensive series of tests with a body-mounted Doppler LIDAR system on-board a track geometry measurement railcar, the study indicates a close match between the LIDAR measurements and those made with existing sensors on-board the railcar. The field testing conducted during this study indicates that LIDAR sensors could provide a reliable, non-contact track monitoring instrument for field use in various weather and track conditions, potentially in a semi-autonomous or autonomous manner.

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Optimizing Tamper Efficiency Through the Integration of Inertial Based Track Geometry Measurement

2017 Joint Rail Conference ◽

10.1115/jrc2017-2255 ◽

2017 ◽

Author(s):

Joseph W. Palese ◽

Sergio DiVentura ◽

Ken Hill ◽

Peter Maurice

Keyword(s):

Time Perspective ◽

Cloud Service ◽

New Method ◽

Maximum Efficiency ◽

Track Geometry ◽

Track Maintenance ◽

Measurement Systems ◽

Recorded Data ◽

Available Technology ◽

Geometry Measurement

Maintaining track geometry is key to the safe and efficient operations of a railroad. Failure to properly maintain geometry can lead to costly track structure failures or even more costly derailments. Currently, there exists a number of different methods for measuring track geometry and then if required, maintaining the track to return track geometry to specified levels of acceptance. Because of this need to have proper track geometry, tampers are one of the most common pieces of maintenance equipment in a railroad operation’s fleet. It is therefore paramount from both a cost and track time perspective to gain maximum efficiency from any one particular tamper. Track geometry is typically measured through a variety of contact and non-contact measurement systems which can mount on a variety of different platforms. With respect to a tamper, a push buggy projector system is typically used to measure track geometry, utilizing the tamper body as the basis for the reference system, Track geometry can be measured utilizing this technology during a prerecording run. Then, the software onboard the tamper analyzes the recorded data to determine the best fit and calculate throws that achieve a better track alignment, particularly in curves. During the tamping operation, the tamper buggy system and frame adjust the track. Due to its design, track geometry measurements can only be made at low speed (roughly 4mph) which can severely affect the efficiency of the tamper. To help decrease pre maintenance inspection times, an inertial based track geometry measurement system has been developed and integrated into the tamper’s operating software. This system can mount directly to the frame of a tamper and operate at hy-rail to very low speeds. Measurements made can be fed directly into the tamper control system to guide where and how track geometry adjustments need to be made. In addition, the capability to collect data during travel mode without the buggies extended allows for the collection of data at any time. Thus, data can be recorded when traveling back and forth to a stabling location, before and/or after grinding. This allows for synchronization of data at a later time to utilize for adjusting the track. Also, data can be collected post-work to allow for the comparison of pre and post geometry to allow for the determination of the effectiveness of a given tamping operation. Tampers equipped with this track geometry system facilitate the foundation for an enterprise solution. Data that is measured and collected can be sent to a cloud service, in real time that will provide exception reports, health status, and rail health trend analyses. Utilizing the available technology further optimizes response time in track maintenance. This paper will introduce this new method of mounting and completely integrating an inertial based track geometry system onto a tamper. In addition, studies will be presented which confirm the ability of this system to replicate the tamper’s projection based track geometry system. Finally, a comprehensive study on efficiency gains will be presented directly comparing a standard method of maintaining a segment via a tamper to this new method of using onboard inertial track geometry measurement.

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FRA Autonomous Track Geometry Measurement System Technology Development: Past, Present, and Future

2014 Joint Rail Conference ◽

10.1115/jrc2014-3860 ◽

2014 ◽

Cited By ~ 2

Author(s):

Soheil Saadat ◽

Cameron Stuart ◽

Gary Carr ◽

James Payne

Keyword(s):

Research And Development ◽

Measurement System ◽

Research Program ◽

Life Cycle Cost ◽

Technology Development ◽

Web Based ◽

Track Geometry ◽

Measurement Systems ◽

Geometry Measurement ◽

Multi Phase

The Federal Railroad Administration’s (FRA’s) Office of Research and Development has undertaken a multi-phase research program focused on the development and advancement of Autonomous Track Geometry Measurement Systems (ATGMS) and related technologies to improve rail safety by increasing the availability of track geometry data for safety and maintenance planning purposes. Benefits of widespread use of ATGMS technology include reduced life-cycle cost of inspection operations, minimized interference with revenue operations, and increased inspection frequencies. FRA’s Office of Research and Development ATGMS research program results have demonstrated that the paradigm of track inspection and maintenance practices, information management and, eventually, government regulations will change as a result of widespread use of ATGMS technology by the industry. A natural consequence of increased inspection frequencies associated with ATGMS is the large amount of actionable information produced. Therefore, changing existing maintenance practices to address a larger number of identified track issues across large geographic areas will be a challenge for the industry. In addition, managing ATGMS data and assessing the quality of this information in a timely manner will be challenging. This paper presents an overview of the FRA’s ATGMS research program with emphasis on its evolution from a proof-of-concept prototype to a fully operational measurement system. It presents the evolution of ATGMS technology over time including the development of a web-based application for data editing, management and quality assurance. Finally, it presents FRA’s vision for the future of the ATGMS technology.

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Developments and applications in the Amtrak track geometry measurement car

10.1117/12.212678 ◽

1995 ◽

Author(s):

Michael Trosino ◽

Ta-Lun Yang ◽

Richard Kelshaw

Keyword(s):

Track Geometry ◽

Geometry Measurement

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Development of an Unattended Track Geometry Measurement System

2010 Joint Rail Conference, Volume 1 ◽

10.1115/jrc2010-36282 ◽

2010 ◽

Author(s):

Graham Scott ◽

Ema Chillingworth ◽

Matthew Dick

Keyword(s):

Measurement System ◽

Cost Effective ◽

Modular System ◽

Integrated Analysis ◽

Management Options ◽

Operational Conditions ◽

Track Geometry ◽

Track Maintenance ◽

Geometry Measurement ◽

And Control

Compliance with track standards and control of maintenance costs are critical aspects of the management of railroads. To facilitate this, track geometry measurement systems have evolved to allow monitoring of key track geometry parameters from moving trains. This paper describes how DeltaRail’s Trackline Two™ track geometry measurement system has been developed to overcome key technical shortcomings in existing systems. The resulting step change provides a cost-effective, robust, compact measurement system suitable for use on the broadest possible range of rail vehicles and networks, from a tram to a TGV. Extensive testing has demonstrated full compliance with appropriate standards. Significant improvements in reliability and repeatability of data have enabled DeltaRail to produce a modular system capable of sending data direct to value-adding analysis tools such as TrackMaster™ and VAMPIRE® so that track maintenance management can be optimized around train fleet and operational conditions. The system is easily operated in unattended mode allowing collection of track geometry data from in-service trains, increased frequency of data collection, and pointing the way for the track maintainers to realize significant value from integrated analysis and management options.

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Track – Bridge Interaction on High Speed Railways – the ONCF Experience

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.d8702.118419 ◽

2019 ◽

Vol 8 (4) ◽

pp. 4607-4612

Keyword(s):

High Speed ◽

Study Phase ◽

Limit Values ◽

Temperature Variations ◽

Track Geometry ◽

Geometry Measurement ◽

Track Bridge ◽

Continuously Welded Rail ◽

To Receive ◽

Current Standards

This paper aims to describe the Moroccan experience on Track – Bridge interaction in railway domain. In fact, that phenomenon may induce a general track instability compromising train security if it’s not taken into account in the study phase. To that end, a numerical method, used to compute the additional longitudinal stresses on a continuously welded rail (CWR) mainly associated to relative displacements between track and deck on account of temperature variations, is presented. Therefore, the conditions of laying an expansion device will be concluded, particularly when the additional rail stresses exceed the maximum limit values defined on the current standards. An application of that method will be performed on MHARHAR viaduct where a non-compliance of track dilatation device laying was noticed. This study will emphasize the beginning of a track grid general instability due to ballast layer deconsolidation, the all based on a track geometry measurement. This study may be widely used in order to conceive properly a bridge supposed to receive a CWR track.

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Multifunction LIDAR Sensors for Non-Contact Speed Measurement in Rail Vehicles: Part 2 — Data Collection and Analysis

2013 Joint Rail Conference ◽

10.1115/jrc2013-2500 ◽

2013 ◽

Author(s):

Shannon Wrobel ◽

Mehdi Ahmadian ◽

Michael Craft ◽

Josh Munoz

Keyword(s):

Ground Truth ◽

Wheel Slip ◽

Ground Speed ◽

Track Geometry ◽

Railroad Industry ◽

Measurement Systems ◽

Rail Vehicles ◽

Data Collection And Analysis ◽

Curvature Measurements ◽

Geometry Measurement

The application of Doppler based, LIght Detection And Ranging (LIDAR or lidar) technology for measuring true ground speed in a non-contacting manner is investigated, as a replacement to wheel tachometers that are commonly used for such measurements. Measuring track speed and distance traveled is an essential part of rail geometry measurement systems. Wheel tachometer measurement accuracy can often be adversely affected by wheel vibrations, change in wheel diameter, and wheel slip in high traction conditions. LIDAR is a non-contact measurement device that uses the Doppler technology to accurately determine speed. Two LIDAR sensors are attached to the underside of a track geometry car with the sensors’ Class I laser beams facing the gauge corner of each rail. The LIDAR sensors measure the absolute ground speed for each rail, allowing for the determination of forward speed and track curvature. The results of the tests show high accuracy in LIDAR speed, distance, and track curvature measurements when compared with other conventional means that are used in the railroad industry and ground truth measurements. With further development, LIDAR sensors can replace wheel tachometers that are commonly used for speed and distance measurement, therefore eliminating the problems with mechanical reliability and the need for periodic calibration of wheel tachometers.

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Novel Algorithm for Mutual Alignment of Railway Track Geometry Measurements

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/03611981211031906 ◽

2021 ◽

pp. 036119812110319

Author(s):

Kristin Eklöf ◽

Andrew Nwichi-Holdsworth ◽

Johan Eklöf

Keyword(s):

Measurement Errors ◽

Measurement Data ◽

Weighted Average ◽

Railway Track ◽

Railway Network ◽

Track Geometry ◽

Spatially Correlated ◽

Geometry Measurement ◽

Variable Sample Rate ◽

Novel Algorithm

Track geometry measurements are regularly collected to monitor the condition of a railway network. To detect deterioration patterns and enable predictive maintenance, sequential measurement runs must be mutually aligned which has been proven a serious challenge. This paper presents a novel algorithm for mutual alignment of track geometry signal data. It resolves several previously intractable alignment problems: highly segmented data with variable sample rate, spatially correlated and uncorrelated measurement errors, convergence to true locations, and consistency over time. The algorithm adjusts spatial measurement errors by splitting signals in continuous segments. Re-sampled, error-corrected signals are mutually aligned using cross correlation, and this process is repeated until the mutual alignment meets a pre-defined precision threshold. Missing measurement values are handled by imputing an interpolated offset from nearby segments, ensuring that the signals remain continuous. By using weighted average offsets over all aligned signals, the law of large numbers guarantees convergence and consistency. The practical feasibility of the algorithm is demonstrated on empirical track geometry measurement data from the British railway network, owned and operated by Network Rail.

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