Novel Algorithm for Mutual Alignment of Railway Track Geometry Measurements

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.

scholarly journals Identification of Temperature-Induced Deformation for HSR Slab Track Using Track Geometry Measurement Data

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5446 ◽  
Author(s):  
Zai-Wei Li ◽  
Xiao-Zhou Liu ◽  
Yue-Lei He
Keyword(s):  
High Speed ◽  
Detection Method ◽  
Measurement Data ◽  
Railway Track ◽  
Discrete Wavelet ◽  
High Speed Rail ◽  
Track Geometry ◽  
Slab Track ◽  
Geometry Measurement ◽  
Inspection Data

Slab track is widely used in many newly built high-speed rail (HSR) lines as it offers many advantages over ballasted tracks. However, in actual operation, slab tracks are subjected to operational and environmental factors, and structural damages are frequently reported. One of the most critical problems is temperature-induced slab-warping deformation (SWD) which can jeopardize the safety of train operation. This paper proposes an automatic slab deformation detection method in light of the track geometry measurement data, which are collected by high-speed track geometry car (HSTGC). The characteristic of track vertical irregularity is first analyzed in both time and frequency domain, and the feature of slab-warping phenomenon is observed. To quantify the severity of SWD, a slab-warping index (SWI) is established based on warping-sensitive feature extraction using discrete wavelet transform (DWT). The performance of the proposed algorithm is verified against visual inspection recorded on four sections of China HSR line, which are constructed with the China Railway Track System II (CRTSII) slab track. The results show that among the 24,806 slabs being assessed, over 94% of the slabs with warping deformation can be successfully identified by the proposed detection method. This study is expected to provide guidance for efficiently detecting and locating slab track defects, taking advantage of the massive track inspection data.

Railway track irregularity and curvature estimation using doppler LIDAR fiber optics

2016 ◽  
Vol 232 (1) ◽  
pp. 63-72 ◽  
Author(s):  
Masood Taheri Andani ◽  
Andrew Peterson ◽  
Josh Munoz ◽  
Mehdi Ahmadian
Keyword(s):  
Fiber Optics ◽  
Field Testing ◽  
Railway Track ◽  
Vehicle Speed ◽  
Doppler Lidar ◽  
Close Match ◽  
Track Geometry ◽  
Lidar Measurements ◽  
Curvature Estimation ◽  
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.

scholarly journals A Novel Short-Range Prediction Model for Railway Track Irregularity

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Peng Xu ◽  
Rengkui Liu ◽  
Quanxin Sun ◽  
Futian Wang
Keyword(s):  
Prediction Model ◽  
Short Range ◽  
Travel Speed ◽  
Railway Track ◽  
Just In Time ◽  
Railway Network ◽  
Track Geometry ◽  
Short Period ◽  
Track Irregularity ◽  
Transport Volume

In recent years, with axle loads, train loads, transport volume, and travel speed constantly increasing and railway network steadily lengthening, shortcomings of current maintenance strategies are getting to be noticed from an economical and safety perspective. To overcome the shortcomings, permanent-of-way departments throughout the world have given a considerable attention to an ideal maintenance strategy which is to carry out appropriate maintenances just in time on track locations really requiring maintenance. This strategy is simplified as the condition-based maintenance (CBM) which has attracted attentions of engineers of many industries in the recent 70 years. To implement CBM for track irregularity, there are many issues which need to be addressed. One of them focuses on predicting track irregularity of each day in a future short period. In this paper, based on track irregularity evolution characteristics, a Short-Range Prediction Model was developed to this aim and is abbreviated to TI-SRPM. Performance analysis results for TI-SRPM illustrate that track irregularity amplitude predictions on sampling points by TI-SRPM are very close to their measurements by Track Geometry Car.

scholarly journals Analyzing Major Track Quality Indices and Introducing a Universally Applicable TQI

2020 ◽  
Vol 10 (23) ◽  
pp. 8490
Author(s):  
Stefan Offenbacher ◽  
Johannes Neuhold ◽  
Peter Veit ◽  
Matthias Landgraf
Keyword(s):  
Measurement Data ◽  
Railway Track ◽  
Quality Indices ◽  
Combine Measurement ◽  
Track Geometry ◽  
University Of Technology ◽  
Track Condition ◽  
Railway Operation ◽  
Selection Of ◽  
Track Quality

Adequate railway track condition is a prerequisite for safe and reliable railway operation. Many track quality indices (TQIs) have been developed with the aim of assessing the track condition holistically. These indices combine measurement signals of some or all relevant geometry parameters with different mathematical models. In this paper, a selection of important TQIs is evaluated. Using measurement data of a five kilometer track section, the indices are calculated and their properties are discussed. This study reveals that all indices exhibit drawbacks to varying degrees. As a consequence, a new index has been developed—the track quality index of Graz University of Technology (TUG_TQI). Its favorable characteristics are presented by means of the above-mentioned test section. The TUG_TQI combines all relevant track geometry parameters, which are normalized beforehand to eliminate over or underrepresentation of different parameters. Thus, the index reliably describes the overall geometrical track quality.

scholarly journals Analysis of railway track geometry measurement methods usability

2018 ◽  
Vol 2018 (8) ◽  
pp. 40-50
Author(s):  
Waldemar Odziemczyk ◽  
Marek Woźniak
Keyword(s):  
Direct Measurement ◽  
Method Development ◽  
Measurement Methods ◽  
Railway Track ◽  
Data Types ◽  
Track Geometry ◽  
Geodetic Measurements ◽  
Accuracy Comparison ◽  
Geometrical Data ◽  
Geometry Measurement

Precise information of railway tracks geometry is necessary to design alignment project. Geodetic measurements are the most common method of determining this information and sags of arch direct measurement are the traditional and still popular measurement method. Development of geodetic measurements techniques made possible to use another methods such as tacheometry, GNSS, and new methods based on mobile measurement devices. Series of experiments were conducted to set the practical usability of selected modern measurement methods to design track alignment project. The experimental measurements were performed on the 3 km long two-track railway fragment. Following methods were used during the test measurements: sags of arch direct measurement, tacheometry with total station, GNSS, automated methods with the use of a trolley system. Above mentioned measurement methods were compared taking into account time and labour consumption, range of geometric data, measurement equipment cost, reliability and accuracy of surveying procedure. Because of different data types are delivered with various methods, sags of arch were used for comparison of accuracy. Comparison of geometrical data obtained with analysed methods allowed to formulate conclusions concerning practical usability those methods for track alignment project development.

scholarly journals Assessment of track and turnout condition based on geometry measurement and railhead condition data

2021 ◽  
Author(s):  
Janusz Madejski
Keyword(s):  
Measurement Data ◽  
Condition Assessment ◽  
Technical Condition ◽  
Track Geometry ◽  
Track Condition ◽  
Train Operation ◽  
Portable Instruments ◽  
Parameters Analysis ◽  
Geometry Measurement ◽  
Inspection Data

The paper presents the procedure of track and turnout geometry condition assessment, taking into account also the deterioration of the rail running surface. Track geometry measurements are made using manual tools, microprocessor-based portable instruments, and geometry cars. Methods of collecting track and turnout geometry data are discussed, and an exemplary equipment design features are presented. Maintaining and possible improvement of the technical condition of the permanent way call for regular inspections providing voluminous data requiring detailed analysis. The approach based on track line-speed dependent geometry parameters analysis is explained. Several synthetic track condition assessment coefficients are described, and analysis of the temporal trend of the track and turnout geometry change. Train operation safety is also affected by changes on the running surface of the rails. In addition to the track geometry, the significant reasons for train operation safety are the railhead wear being affected by the type of transport, traffic intensity and maximum allowable axle load. Determining the permanent way condition with the continuous design and maintenance characteristics is possible if measured on the minimum 200-300 m length with the measurement steps of ca 0.5 m. Comments on employing the Artificial Intelligence tools for track and turnout condition analysis are provided. Most of the inspection data collected using various equipment, like track and turnout geometry measurement data and video inspection information, can be analysed automatically by the dedicated software agents. Such an approach yields analysis results equivalent to the standard inspections, except that the trains and self-propelled trolleys can record data at higher speeds, railways staff could achieve.

Dynamic Measurement of Spatial Attitude at Bottom Rotating Drillstring: Simulation, Experimental, and Field Test

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Qilong Xue ◽  
Ruihe Wang ◽  
Baolin Liu ◽  
Leilei Huang
Keyword(s):  
Real Time ◽  
Measurement Errors ◽  
Time Window ◽  
Measurement Data ◽  
Movement Patterns ◽  
Dynamic Measurement ◽  
Drilling Process ◽  
Stick Slip ◽  
Actual Measurement ◽  
Gas Drilling

In the oil and gas drilling engineering, measurement-while-drilling (MWD) system is usually used to provide real-time monitoring of the position and orientation of the bottom hole. Particularly in the rotary steerable drilling technology and application, it is a challenge to measure the spatial attitude of the bottom drillstring accurately in real time while the drillstring is rotating. A set of “strap-down” measurement system was developed in this paper. The triaxial accelerometer and triaxial fluxgate were installed near the bit, and real-time inclination and azimuth can be measured while the drillstring is rotating. Furthermore, the mathematical model of the continuous measurement was established during drilling. The real-time signals of the accelerometer and the fluxgate sensors are processed and analyzed in a time window, and the movement patterns of the drilling bit will be observed, such as stationary, uniform rotation, and stick–slip. Different signal processing methods will be used for different movement patterns. Additionally, a scientific approach was put forward to improve the solver accuracy benefit from the use of stick–slip vibration phenomenon. We also developed the Kalman filter (KF) to improve the solver accuracy. The actual measurement data through drilling process verify that the algorithm proposed in this paper is reliable and effective and the dynamic measurement errors of inclination and azimuth are effectively reduced.

scholarly journals The Design and Implementation of an Inertial GNSS Odometer Integrated Navigation System Based on a Federated Kalman Filter for High-Speed Railway Track Inspection

2021 ◽  
Vol 11 (11) ◽  
pp. 5244
Author(s):  
Xinchun Zhang ◽  
Ximin Cui ◽  
Bo Huang
Keyword(s):  
Kalman Filter ◽  
Navigation System ◽  
High Speed ◽  
Measurement Accuracy ◽  
Railway Track ◽  
Filter Method ◽  
Integrated Navigation ◽  
High Speed Railway ◽  
Track Geometry ◽  
Integrated Navigation System

The detection of track geometry parameters is essential for the safety of high-speed railway operation. To improve the accuracy and efficiency of the state detector of track geometry parameters, in this study we propose an inertial GNSS odometer integrated navigation system based on the federated Kalman, and a corresponding inertial track measurement system was also developed. This paper systematically introduces the construction process for the Kalman filter and data smoothing algorithm based on forward filtering and reverse smoothing. The engineering results show that the measurement accuracy of the track geometry parameters was better than 0.2 mm, and the detection speed was about 3 km/h. Thus, compared with the traditional Kalman filter method, the proposed design improved the measurement accuracy and met the requirements for the detection of geometric parameters of high-speed railway tracks.

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

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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