Journal articles: 'Irregularity on the railroad track'

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Li, Jun Li. "An Inspection System and Measurement Algorithm of Geometry Status of Railroad Tracks." Applied Mechanics and Materials 241-244 (December 2012): 50–55. http://dx.doi.org/10.4028/www.scientific.net/amm.241-244.50.

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A tracks status inspection system based on coordinate transformation matrix algorithm was introduced. The structure, composition, measurement principles, design and test of the inspection system were elaborated. It was composed of two handy carts. Variation of tracks status could be denoted by three relative turning angles under the two coordinate systems of the two carts by means of coordinate transformation matrix, and tracks geometry parameters could be obtained using the matrix recursion algorithm. The instrumentation can carry out inspections such as track height, height irregularity, level irregularity, track gauge, track alignment and triple pit and so on.

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Vitalii, Kovalchuk, Kovalchuk Yuri, Sysyn Mykola, Stankevych Volodymyr, and Petrenko Oleksiy. "ESTIMATION OF CARRYING CAPACITY OF METALLIC CORRUGATED STRUCTURES OF THE TYPE MULTIPLATE MP 150 DURING INTERACTION WITH BACKFILL SOIL." Eastern-European Journal of Enterprise Technologies 1, no. 1 (91) (2018): 18–26. https://doi.org/10.15587/1729-4061.2018.123002.

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We estimated the stressed state of a railroad structure with a large cross section spanning more than 6 m, which is made from metallic corrugated sheets of the type Multiplate MP 150. The stressed-strained state of the corrugated structure was estimated depending on the residual deformation of vertical diameter of the pipe, the modulus of elasticity of backfill soil, and the degree of compaction. The study conducted has demonstrated that maximum stresses occur on the horizontal sides of a metallic pipe, and maximum deformations – in the pipe vault. It was established that an increase in the degree of compaction of backfill soil leads to a decrease in the stresses in a metallic pipe by almost half. The stresses grow much faster with an increase in irregularity on the railroad track. Numerical calculations have shown that the equivalent stresses exceed the permissible magnitude of 235 MPa when the degree of compaction of backfill soil is below 90 % and an operational irregularity on the track develops beyond the permissible magnitude. Operational observations have shown that the pipe is most vulnerable, in terms of resistance against the formation of a plastic hinge, in the initial period of operation when the backfill soil has not yet reached the standard compaction. At the initial stage of operation of a metallic corrugated pipe it is necessary to improve the level of technological control in order to timely detect railroad track’s irregularities that exceed the standards, and to eliminate them. Under normal operational conditions, a metallic corrugated structure has a rather large reserve of carrying capacity, which amounts to 80 %. However, these structures, despite their high initial strength margin, are very sensitive to an increase in external dynamic loads due to the occurrence of irregularity on the railroad track

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D., M. Kurhan. "MODELING OF DEVELOPMENT VERTICAL DEFORMATION OF RAILWAY TRACK." Science and Transport Progress. Bulletin of Dnipropetrovsk National University of Railway Transport, no. 1(61) (February 25, 2016): 100–108. https://doi.org/10.15802/stp2016/61003.

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Purpose. State of railway track must meet the conditions of safety, comfort and smooth ride. The presence of irregularities deteriorates the dynamics of interaction of track and rolling stock, causes speed limiting, creates the possibility of movement safety violation. This brings up the question concerning the study of the factors leading to the possibility of track irregularities and the process of their development. The purpose of this paper is to analyse the processes of emergence and development of irregularities in the area of unequal vertical elasticity of railway track using mathematical modelling. Methodology. Railroad under the trains works as the system of elastic bodies, so the emergence and development of irregularities can be represented as the transition from elastic to permanent strain. Irregularity development will affect the dynamics of interaction between track and rolling stock not only at the wheel location directly in the area of irregularity, but also at a certain distance beyond. Therefore, to study the development of irregularities, including those along the track, it is necessary to model the process of wheel load movement along the area. The adopted model consists of a wheel set moving on  inertia-free beam and resting on individual supports. It is described by Lagrange differential equations. The work introduced the hypothesis that the level of permanent strain is distributed in proportion to the dynamic deflection derivative. Findings. Location of vertical longwise irregularity does not necessarily reproduce the location of the problem area. While in operation the vertical irregularity extends not only in depth but also along the track, herewith the increase in length is accompanied by the displacement of local maxima and the emergence of new ones. This leads to the development of so-called «pits» when approaching unequal-elastic areas. Originality. The work provides further development of tasks for track and rolling stock interaction modelling, in particular aimed to take into account the unequal elasticity areas and their influence on the formation of the track irregularities. The paper proposes new approaches to modelling the transition from elastic to permanent strain that allows predicting the development of track irregularity sizes depending on the area characteristics. Practical value. The results obtained by the author can be used to determine the schedule for track equal elasticity renovation works, as well as to analyse the measures aimed at the prevention of irregularities in areas with variable elasticity of railway track.

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Loic Chango, Ishola Valere, Goubi Cyriaque Assogba, Muhan Yan, Ling Xianzhang, and Josue Girece Mitobaba. "Impact Assessment of Asphalt Concrete in Geogrid-Reinforced-Pile-Supported Embankment During High-Speed Train Traffic." Baltic Journal of Road and Bridge Engineering 17, no. 2 (2022): 135–63. http://dx.doi.org/10.7250/bjrbe.2022-17.563.

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Railroad structural behaviour is a significant factor for safety and comfort during high-speed train operation. Intending to improve railway performance, increase its bearing capacity, and reduce vibrations induced by train passage, asphalt concrete has become a material to be integrated into railway construction. Despite several studies evaluating asphalt concrete effect on the railway mechanical behaviour, its impact assessment remains poorly understood. This study investigates the impact of asphalt concrete material in the geogrid-reinforced-pile-supported embankment structure subjected to high-speed train moving. A 3D nonlinear finite element model was developed to simulate Harbin (Dalian (China) instrumented railroad test section accurately. The high-speed train moving load was modelled as a transitory dynamic load via a user-defined subroutine 3D load in which the track irregularity is incorporated. The established model was effectively validated by the vibration acceleration and stress measured in the field test section. The asphalt concrete viscoelasticity behaviour was incorporated into the 3D geogrid-reinforced-pile-supported embankment finite element model through the Prony series to characterise its mechanical response better. The impact of asphalt concrete material in maintaining a low and constant structural vibration, regardless of train weight level, moving speed variations, and weather conditions were investigated, analysed and discussed.

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Gonçalves, Vítor, Araliya Mosleh, Cecília Vale, and Pedro Aires Montenegro. "Wheel Out-of-Roundness Detection Using an Envelope Spectrum Analysis." Sensors 23, no. 4 (2023): 2138. http://dx.doi.org/10.3390/s23042138.

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This paper aims to detect railway vehicle wheel flats and polygonized wheels using an envelope spectrum analysis. First, a brief explanation of railway vehicle wheel problems is presented, focusing particularly on wheel flats and polygonal wheels. Then, three types of wheel flat profiles and three periodic out-of-roundness (OOR) harmonic order ranges for the polygonal wheels are evaluated in the simulations, along with analyses implemented using only healthy wheels for comparison. Moreover, the simulation implements track irregularity profiles modelled based on the US Federal Railroad Administration (FRA). From the numerical calculations, the dynamic responses of several strain gauges (SGs) and accelerometer sensors located on the rail between sleepers are evaluated. Regarding defective wheels, only the right wheel of the first wheelset is considered as a defective wheel, but the detection methodology works for various damaged wheels located in any position. The results from the application of the methodology show that the envelope spectrum analysis successfully distinguishes a healthy wheel from a defective one.

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Luo, Hao, Chuyi Xu, Xianbei Gan, Mougang Liu, Xiangrong Guo, and Hui Guo. "The Train-Bridge Coupled Vibration Analysis of a Long-Span Prestressed Concrete Continuous Beam Bridge under Creep Deformation Effect." Applied Sciences 12, no. 22 (2022): 11838. http://dx.doi.org/10.3390/app122211838.

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The track smoothness of high-speed railroads is severely limited to ensure train performance. The concrete continuous girder bridge is deformed to influence the smoothness of the bridge decks and track caused by creep bulge. There is a need to research the impact of beam creep on the dynamical response of bridge and train operation safety. This paper used Midas software to calculate the long-term deformation of large-span prestressed concrete continuous beam bridges under concrete creep and shrinkage. The train-bridge coupled system was established by adopting self-programming software. Thereafter, the large-term deformation results of the main girder are considered as track irregularity input into the vibration equation of the train-bridge system. The safety of the train operation was evaluated by calculating the dynamic response of the bridge and analyzing the criteria of train running safety. It was shown that the indicators of the large-span bridge are within the allowable code values under all working conditions. The bridge deformation under creep has an impact on the displacement and acceleration response of the bridge when a high-speed train passes through. There is no noticeable impact of creep deformation on the operational performance of trains. Nevertheless, the criteria for assessing the safety of trains’ operation, such as derailment factor, wheel load differences, lateral wheel forces, and vehicle acceleration, have been increased.

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Zhong, Chun Yan, and Yu De Xu. "Forecast Method Study on Track Longitudinal Level Irregularity Based on Most Possible Similarity Model." Advanced Materials Research 779-780 (September 2013): 1705–10. http://dx.doi.org/10.4028/www.scientific.net/amr.779-780.1705.

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Track irregularity is objective existence, it cant be eliminated. But, we can formulate reasonable repair and maintenance plans to increase the efficiency of track maintenance and ensure safety, if the prediction of track irregularity is effective. In this paper, on the basis of analyzing on the irregularity forecast method and the "memory" of ballast track, a method based on most possible similarity model is introduced. This method is going to find irregularity in history most close to the current, and use its development to predict the current development. The longitudinal level irregularity of Hefei-Wuhan line was predicted, and results indicate that prediction graphics were consistent with the actual graphics in trend. So, using this model to predict development trend of track longitudinal irregularity is feasible.

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Zhai, Hong Bing, and Chao Long Jia. "Analysis of Incidence of Rail Failure and Track Composite Irregularity State Forecast." Applied Mechanics and Materials 300-301 (February 2013): 802–5. http://dx.doi.org/10.4028/www.scientific.net/amm.300-301.802.

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Rail failure and track composite irregularity is the source of violent harassment of the wheel-rail system. Track irregularity has significant impact on the driving security and stability of the train. At present, the focus of the Chinese railway development is high speed, heavy haul and shortcut transportation, thus the influences of rail failure and track composite irregularity will be more remarkable, which has become a primary factor that limits the running speed. This paper analyzes the characters of rail failure and formation mechanism of the track irregularity, forecasts the trend of track irregularity development and explores the hidden risks that might occur and influence the safety of railway traffic.

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Jia, Chaolong, Lili Wei, Hanning Wang, and Jiulin Yang. "Study of Track Irregularity Time Series Calibration and Variation Pattern at Unit Section." Computational Intelligence and Neuroscience 2014 (2014): 1–14. http://dx.doi.org/10.1155/2014/727948.

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Focusing on problems existing in track irregularity time series data quality, this paper first presents abnormal data identification, data offset correction algorithm, local outlier data identification, and noise cancellation algorithms. And then proposes track irregularity time series decomposition and reconstruction through the wavelet decomposition and reconstruction approach. Finally, the patterns and features of track irregularity standard deviation data sequence in unit sections are studied, and the changing trend of track irregularity time series is discovered and described.

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Bednarek, Włodzimierz Andrzej. "The problems of arising vertical irregularities in operating railway track." Transportation Overview - Przeglad Komunikacyjny 2016, no. 2 (2016): 9–22. http://dx.doi.org/10.35117/a_eng_16_02_02.

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Arising during railway track structure operating the geometrical irregularities of track in vertical plane are the additional sources of interaction between the trains and track. These irregularities have got an unintentional character (arising in random way during track operating, e.g. irregularities in track, change of track geometrical parameters or inhomogeneity of track support) and intentional character (arising e.g. during railway track lifting by VSS plate). The unintentional irregularity causes among other things an additional increase of deflections and stresses in track structure elements, which lead to failures and wear of track elements. Such arising the longitudinal irregularity in track is the reason for various forms of contact between sleeper and ballast. Track stiffness in unloaded state (without forces from trains) causes that the sleepers in various ways rest on the ballast. The analysis of load transfer from wheel by rail to the railway sleeper allows for visualizing the effects of such irregularity for railway track. Furthermore a shape of arising irregularity causes the decrease of train wheel traction efficiency understanding as the degree of its tractive adhesion utilization resulting from static loads. In paper an experimental analysis of arising irregularity in CWR track during its operating is enclosed.

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Niu, Liubin, Jinzhao Liu, and Yunlai Zhou. "Track Irregularity Assessment in High-Speed Rail by Incorporating Carriage-Body Acceleration with Transfer Function." Mathematical Problems in Engineering 2020 (June 27, 2020): 1–16. http://dx.doi.org/10.1155/2020/8414531.

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The determination of the precise track irregularity with unfavorable wavelength, which shall induce vehicle’s violent vibration in terms of the vehicle’s speeds, still challenges the researchers. This study proposes a feasible study of assessing the track irregularity by using the transfer function and the measured carriage-body acceleration by combining the ARX model with state space model. The ARX model and state space model are constructed using system identification to obtain the transfer relation between the track irregularity and the carriage-body acceleration, respectively. The model’s parameters are estimated by the measured data from the high-speed China Railway Comprehensive Inspection Train (CRCIT). The correlation value between the predicted and measured carriage-body acceleration shows that both models can effectively represent the transfer characteristics between the track irregularity and the carriage-body acceleration. Furthermore, the models can help assess the proportion of the vibration caused by track irregularity with the specific wavelengths and determine the track irregularity with unfavorable wavelength.

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TSAI, HSIN CHU, CHUNG YUE WANG, and NORDEN E. HUANG. "FAST INSPECTION AND IDENTIFICATION TECHNIQUES FOR TRACK IRREGULARITIES BASED ON HHT ANALYSIS." Advances in Adaptive Data Analysis 04, no. 01n02 (2012): 1250016. http://dx.doi.org/10.1142/s1793536912500161.

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The requirements for inspection and management of track irregularity have to be more rigorous due to safety and serviceability concerns as the increment of the train speed of high-speed train. The wavelength of track irregularity significantly affects running safety and riding comfort. To improve inspection, operation, efficiency, and address, the inability of the mid-chord offset method currently used on track inspection cars to identify some irregularity wavelengths, a measurement and assessment method is presented in this paper. Nonstationary and nonlinear vehicle dynamic response data caused by irregularities were measured by accelerometers mounted on the axle-box of a vehicle. The Hilbert–Huang transform (HHT) technique was applied to analyze the data. Components of specific irregularity wavelength could be effectively identified and accurately matched to the data measured by the track inspection car. Additionally, to obtain the complete waveform of the track irregularity, we propose a restoration method of track irregularity that combines the characteristics of the measurement magnification in the chord-based measuring system and the HHT signal-processing techniques.

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Podwórna, M. "Modelling Of Random Vertical Irregularities Of Railway Tracks." International Journal of Applied Mechanics and Engineering 20, no. 3 (2015): 647–55. http://dx.doi.org/10.1515/ijame-2015-0043.

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Abstract The study presents state-of-the-art in analytical and numerical modelling of random vertical irregularities of continuously welded ballasted railway tracks. The common model of railway track irregularity vertical profiles is applied, in the form of a stationary and ergodic Gaussian process in space. Random samples of track irregularity vertical profiles are generated with the Monte-Carlo method. Based on the numerical method developed in the study, the minimum and recommended sampling number required in the random analysis of railway bridges and number of frequency increments (harmonic components) in track irregularity vertical profiles simulation are determined. The lower and upper limits of wavelengths are determined based on the literature studies. The approach yields track irregularity random samples close to reality. The track irregularity model developed in the study can be used in the dynamic analysis of railway bridge / track structure / highspeed train systems.

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Hwang, Sung Ho, Sungil Kim, Kyoung-Chan Lee, and Seung Yup Jang. "Effects of Long-Wavelength Track Irregularities Due to Thermal Deformations of Railway Bridge on Dynamic Response of Running Train." Applied Sciences 8, no. 12 (2018): 2549. http://dx.doi.org/10.3390/app8122549.

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In a fixed-end arch railway bridge restraining the displacement and rotation at the support to constrain the longitudinal deformation of the superstructure, vertical deformation occurs according to temperature change. Due to such deformation, periodic change in long-wavelength track irregularity occurs, which, by increasing the vertical train body acceleration, degrades ride comfort. In the present study, the vertical deformation of a fixed-end arch railway bridge and the accompanying track irregularity changes were measured during the summer and winter, respectively. Based on the measured data, the relationships among the ambient temperature, the temperature of the bridge members, the deformation of the bridge, and the track irregularity were investigated. Additionally, the correlation between the train body acceleration and the long-wavelength track irregularity was examined, and a method of controlling long-wavelength track irregularity considering seasonal temperature change was discussed.

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Kota, P. N., Aditya Pal, and Amit Vitekar. "Railroad Track Maintenance Device." International Journal on Communications Antenna and Propagation (IRECAP) 7, no. 6 (2017): 476. http://dx.doi.org/10.15866/irecap.v7i6.13605.

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Bridger, Maxine. "The Railroad-Track Problem." Mathematics Teacher 85, no. 6 (1992): 439–41. http://dx.doi.org/10.5951/mt.85.6.0439.

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Mukherjee, Kanchan Kuntala, Paramita Banerjee, and Arlene Zide. "Along the Railroad Track." Chicago Review 38, no. 1/2 (1992): 122. http://dx.doi.org/10.2307/25305574.

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Shi, Hong Mei, and Jia Liang Zhou. "Vibration Analysis of High-Speed Vehicles under the Condition of Track Random Irregularity." Advanced Materials Research 211-212 (February 2011): 525–29. http://dx.doi.org/10.4028/www.scientific.net/amr.211-212.525.

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Track irregularity is the most important excitation source of wheel-rail system. The vibration characteristics of vehicle components and track components are analyzed in this paper under the condition of track irregularity by establishing the vehicle - track vertical coupling model. And the establishment of vibration differential equation and numerical simulation method for solving vibration response are described in detail. Finally, the results are given by MATLAB. The method is of great significance for evaluating the dynamic track irregularity and vehicle’s vibration at different running speeds.

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Tsunashima, Hitoshi, and Nozomu Yagura. "Railway Track Irregularity Estimation Using Car Body Vibration: A Data-Driven Approach for Regional Railway." Vibration 7, no. 4 (2024): 928–48. http://dx.doi.org/10.3390/vibration7040049.

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Track and preventive maintenance are necessary for the safe and comfortable operation of railways. Track displacement measured by track inspection vehicles or trolleys has been primarily used for track management. Thus, vibration data measured in in-service vehicles have not been extensively used for track management. In this study, we propose a new technique for estimating track irregularities from measured car body vibration for track management. The correlation between track irregularity and car body vibration was analysed using a multibody dynamics simulation of travelling rail vehicles. Gaussian process regression (GPR) was applied to the track irregularity and car body vibration data obtained from the simulation, and a method was proposed to estimate the track irregularities from the constructed regression model. The longitudinal-level, alignment, and cross-level irregularities were estimated from the measured car body vibrations and travelling speeds on a regional railway, and the results were compared with the actual track irregularity data. The results showed that the proposed method is applicable for track irregularity management in regional railways.

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Zhang, Yuan. "Spatial Coupling Vibration of Vehicle-Track-Bridge System due to Different Track Irregularities." Advanced Materials Research 255-260 (May 2011): 1735–39. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.1735.

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Track irregularity is one of the most important factors that induce vehicle-track-bridge coupling vibration. In this paper, spatial model of vehicle- track-bridge system is established. The track irregularity sample in time domain are established by power spectrum density and taken as the exciting source to analyze the spatial coupling vibration of vehicle-track-bridge system. By comparing the vibration responses of the model excited by vertical profile irregularity and the model excited by four different irregularities, the change of track irregularities have mostly influence on the vibration of the parts above the rail and nearly no influence on the parts under the rail and bridge.

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Xu, Peng, Chuanjun Jia, Ye Li, Quanxin Sun, and Rengkui Liu. "Developing an Enhanced Short-Range Railroad Track Condition Prediction Model for Optimal Maintenance Scheduling." Mathematical Problems in Engineering 2015 (2015): 1–12. http://dx.doi.org/10.1155/2015/796171.

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As railroad infrastructure becomes older and older and rail transportation is developing towards higher speed and heavier axle, the risk to safe rail transport and the expenses for railroad maintenance are increasing. The railroad infrastructure deterioration (prediction) model is vital to reducing the risk and the expenses. A short-range track condition prediction method was developed in our previous research on railroad track deterioration analysis. It is intended to provide track maintenance managers with two or three months of track condition in advance to schedule track maintenance activities more smartly. Recent comparison analyses on track geometrical exceptions calculated from track condition measured with track geometry cars and those predicted by the method showed that the method fails to provide reliable condition for some analysis sections. This paper presented the enhancement to the method. One year of track geometry data for the Jiulong-Beijing railroad from track geometry cars was used to conduct error analyses and comparison analyses. Analysis results imply that the enhanced model is robust to make reliable predictions. Our in-process work on applying those predicted conditions for optimal track maintenance scheduling is discussed in brief as well.

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Dai, Guang Yu, Jun Zhang, Kun Lin Lü, et al. "Online Real-Time Detection Method for Defects of Railroad Track Surface." Applied Mechanics and Materials 321-324 (June 2013): 1017–20. http://dx.doi.org/10.4028/www.scientific.net/amm.321-324.1017.

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In the field of detecting for defects of railroad track surface, computer vision method for detection has been widely used. An online real-time image processing system for defects of railroad track surface is introduced in the paper. Results show that: if the number of pixels in each railroad track surface image is 512×240, the train speed can be 50 Km/h while the image processing system can real-time detect the railway track surface defects, the number of pixels in in each railroad track surface image is 320×250, the train speed can be 100 Km/h while the image processing system can real-time detect the railway track surface defects.

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Köllő, Szabolcs Attila, Attila Puskás, and Gavril Köllő. "Ballasted Track versus Ballastless Track." Key Engineering Materials 660 (August 2015): 219–24. http://dx.doi.org/10.4028/www.scientific.net/kem.660.219.

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First concrete sleepers were made of normal reinforced concrete and used during the 1930s and 1940s. Concrete railroad ties became popular in Europe after World War II because of the advances in design, material quality and production of pre-stressed concrete. Now as before, concrete sleepers on ballast represent the primary basis of track construction, around the world, but the twin block concrete sleepers are also popular and widely used. The continuously increasing operational loads and speeds forced the railway companies to update their technical and economic system to keep their vital role in transporting passengers and merchandise. In this development a very important role played the superstructure of the railroad system, and this modernization process led to appearing of the ballastless track system approximately 60 years ago. The article presents a comparison of two main types of track systems, including technical and economic aspects.

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M B, Dr Suresh. "Accident Avoidance using Railway Track Detection System using IoT." INTERANTIONAL JOURNAL OF SCIENTIFIC RESEARCH IN ENGINEERING AND MANAGEMENT 08, no. 04 (2024): 1–5. http://dx.doi.org/10.55041/ijsrem29770.

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An IoT-based railway track crack and object discovery framework is an innovative arrangement for guaranteeing the security of railroad frameworks. The framework employs a combination of sensors and cameras that are introduced along the railroad track to screen it for any signs of harm or hindrances. The sensors can identify vibrations and changes within the track, which can show the nearness of a break or other sort of harm. The cameras can capture pictures and video of the track, such as fallen branches, flotsam, and jetsam, or indeed individuals or creatures. Once the framework recognizes an issue, it can send an alarm to the railroad administrators or upkeep workforce, permitting them to rapidly address the issue sometime soon if it causes any mischances or delays. An IOT-based railroad track break and protest location framework can incredibly move forward the security and proficiency of railroad operations. Key Words: Embedded system, Internet of things, ultrasonic sensor, IR detector, Arduino Uno, GPS

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Xu, Peng, Rengkui Liu, Quanxin Sun, and Futian Wang. "A Novel Short-Range Prediction Model for Railway Track Irregularity." Discrete Dynamics in Nature and Society 2012 (2012): 1–12. http://dx.doi.org/10.1155/2012/591490.

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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.

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Mo, Ye, Yi Zhuo, and Shunlong Li. "Local Track Irregularity Identification Based on Multi-Sensor Time–Frequency Features of High-Speed Railway Bridge Accelerations." Sustainability 15, no. 10 (2023): 8237. http://dx.doi.org/10.3390/su15108237.

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Shortwave track diseases are generally reflected in the form of local track irregularity. Such diseases will greatly impact the train–track–bridge interaction (TTBI) dynamic system, seriously affecting train safety. Therefore, a method is proposed to detect and localize local track irregularities based on the multi-sensor time–frequency features of high-speed railway bridge accelerations. Continuous wavelet transform (CWT) was used to analyze the multi-sensor accelerations of railway bridges. Moreover, time–frequency features based on the sum of wavelet coefficients were proposed, considering the influence of the distance from the measurement points to the local irregularity on the recognition accuracy. Then, the multi-domain features were utilized to recognize deteriorated railway locations. A simply-supported high-speed railway bridge traversed by a railway train was adopted as a numerical simulation. Comparative studies were conducted to investigate the influence of vehicle speeds and the location of local track irregularity on the algorithm. Numerical simulation results show that the proposed algorithm can detect and locate local track irregularity accurately and is robust to vehicle speeds.

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Gao, Liang, Wenqiang Zhao, Bowen Hou, and Yanglong Zhong. "Analysis of Influencing Mechanism of Subgrade Frost Heave on Vehicle-Track Dynamic System." Applied Sciences 10, no. 22 (2020): 8097. http://dx.doi.org/10.3390/app10228097.

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Uneven subgrade frost heave has been a severe problem for the operation of high-speed railways in cold regions. In order to reveal the influencing mechanism of frost heave on the vehicle-track system, a novel FEM (finite element method) model based on an explicit algorithm was proposed. In the novel model, the existence of the leverage effect in slab track, which was caused by frost heave, was realistically reproduced at first, and then the vehicle model started running for evaluating the influence of the frost heave on the whole dynamic system. Results show that the leverage effect plays a key role in analyzing the influence of frost heave on the vehicle-track system, besides for track irregularity and contact loss. Specifically, the leverage effect decreases the stability of the slab track and causes an increase in dynamic irregularity. The roles of the track irregularity and the contact loss in the influencing mechanism were also revealed. With the ratio of wavelength to amplitude increasing, the track irregularity is gradually dominant in the influence mechanism of frost heave on the vehicle-track system. The research could provide a reference for the management and maintenance of the slab track in cold regions.

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Liu, Xiao-Zhou, Zai-Wei Li, Jun Wu, Cheng-Jie Song, and Jun-Hua Xiao. "Correlation Analysis between Rail Track Geometry and Car-Body Vibration Based on Fractal Theory." Fractal and Fractional 6, no. 12 (2022): 727. http://dx.doi.org/10.3390/fractalfract6120727.

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The effect of track geometry on vehicle vibration is a major concern in high-speed rail (HSR) operation from the perspectives of ride comfort and safety. However, how to quantitatively characterize the relation between them remains a problem to be solved in track quality assessment. By using fractal analysis, this paper studies the detailed correlation between track surface and alignment irregularities and car body vertical and lateral acceleration in various wavelength ranges. The time-frequency features of the track irregularity and car-body acceleration are first analyzed based on empirical mode decomposition (EMD). Then, the fractal features of the inspection data are determined by calculating the Hurst exponent of their intrinsic mode functions (IMFs). Finally, the fractal dimensions of the track irregularity and car-body acceleration are obtained, and the correlation between their fractal dimensions with respect to different IMFs is revealed using regression analysis. The results show that the fractal dimension is only related to the roughness of the IMF waveforms of the track irregularity and car-body vibration and is irrelevant to the amplitude of the time series of the data; the correlation coefficient of the fractal dimension of the track irregularity and car-body acceleration is greater than 0.7 for wavelengths greater than 30 m, indicating that the relationship between track irregularity and car-body vibration acceleration is more obvious for long wavelengths. The findings of this research could be used for optimizing HSR track maintenance work from the viewpoint of the ride quality of high-speed trains.

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Zhou, Ge. "Railway Track Irregularity Data Mining and Time Series Trend Forecasting Research." Applied Mechanics and Materials 666 (October 2014): 272–75. http://dx.doi.org/10.4028/www.scientific.net/amm.666.272.

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Railway track ride is one of the important indicators of the state of the tracks,This article making railway track irregularity data mining,The paper railway track irregularity data mining,data analysis implied regularity and A mathematical model to predict the time-series trends in research,Analysis of the data implied regularity and Build mathematical model getting on time series trend forecasting research.

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30

Song, Rong Rong, Wei Hua Ma, and Zi Li Chen. "Study on Improved Fuzzy Immune PID Controller for Maglev Transportation System with Track Irregularity." Applied Mechanics and Materials 423-426 (September 2013): 2825–31. http://dx.doi.org/10.4028/www.scientific.net/amm.423-426.2825.

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Track irregularity is one of the most important aspects of the suspension control performance impact in maglev transportation system (MTS). Due to the track irregularity phenomenon of suspension system, the Fuzzy PID(F-PID) control is unable to accurately track irregularity of track changes. Based on the qualitative analysis to MTS, through modifying conventional F-PID controller, the article establishes Fuzzy Immune PID(FI-PID) Controller based on the biological immune system theory. The control strategy designed nonlinear P controller, using the immune algorithm of on-line adjustment of P and the fuzzy control approximating the nonlinear function of the immune P control parameters and the fuzzy control designed the ID controller for adjusting the parameters of I and D for enhancing the robust performance of the suspension system and adapting to the change of track irregularity. Simulation results show that the FI-PID control is confirmed more effectively to realize tracking compared with F-PID, faster response speed, more simple structure, easier operation for the track interference and load disturbance of the suspension system. This provides a very good way to solve the interference problem of orbit of the maglev transportation system.

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31

Song, Rong Rong, and Zi Li Chen. "Research on the Delay Suspension System Based on Different Learning Rules." Applied Mechanics and Materials 380-384 (August 2013): 676–80. http://dx.doi.org/10.4028/www.scientific.net/amm.380-384.676.

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Track irregularity is one of the most important aspects of the suspension control performance impact. Due to the delay phenomenon of suspension system, the traditional PID control is unable to accurately track irregularity of track changes. Based on the qualitative analysis to delay suspension system, through modifying conventional PID controller, the article establishes four kinds of Neural Network adaptive PID Controllers based on different learning rules. The control strategy combines by the simple structure of the PID Control, the self-organizing ability of the Neural Network Control and the self-learning ability of the learning rules, adjusts PID parameters on-line, adapts to the change of track irregularity, and has strong robustness. However, the different learning rules have different learning ability of the interferences of track irregularity for the delay phenomenon of the suspension system. Simulation result shows that the supervised Delta learning rules is confirmed more effectively to realize tracking compared with other learning rules, faster response speed, more simple structure, easier operation for the track interference and load disturbance of the delay suspension system. This provides a very good way to solve the interference problem of orbit of the delay suspension system.

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32

Lestari, Sachiko Mawaddah, and Muhammad Fauzan. "Analysis of the Implementation of the South Sumatra Transit Light Rail Slab Track." Jurnal Perkeretaapian Indonesia 1, no. 2 (2017): 151–58. http://dx.doi.org/10.37367/jpi.v1i2.42.

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Transportation has an important role in supporting economic growth, development and unifying the territory of the Unitary Republic of Indonesia, in order to improve transportation services in supporting development in South Sumatra Province, and supporting the implementation of the 2018 Asian Games, it is necessary to accelerate the implementation of Light Rail Transit in the province of South Sumatra. This is related to the Republic of Indonesia's Presidential Regulation Number 116 of 2015 concerning the Acceleration of the Operation of Light Rail Transit in South Sumatra Province. At the railroad track in Indonesia there is currently no railroad that has operated using the slab track construction but at this time the Government of Indonesia is conducting railroad construction in Indonesia on a national scale. In the construction of the South Sumatra LRT (Light Rail Transit) is a power railroad construction electricity that is in the process of development that will use modern railroad construction that is using slab track construction. In this very happy opportunity the writer got the opportunity to do research at the South Sumatra LRT Work Unit because the South Sumatra LRT is under construction. South Sumatra LRT uses elevated road construction using slab track construction. At present the South Sumatra LRT is the first project to undertake slab track construction in Indonesia. In fact, there is no railroad in Indonesia that operates using slab track construction.

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33

An, Bolun, Pu Wang, Shuai Ma, Zhuoran Ma, Yanglong Zhong, and Wenqiang Zhao. "Influence of Metro Track Irregularities on Pantograph Vibration and Its Interaction with Catenary." Applied Sciences 12, no. 13 (2022): 6435. http://dx.doi.org/10.3390/app12136435.

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The problem of excessive wear of pantograph strips frequently occurs on China’s Z City Metro Line 1. After on-site investigation and analysis by the metro operating company, it was speculated that the problem was related to abnormal track irregularities. Therefore, taking Z City Metro Line 1 as the main research object, the measured track irregularity of the whole line was analyzed and compared with other typical track spectra, and a track-vehicle-pantograph-catenary coupling dynamics model was established to analyze the relationship between the pantograph-catenary dynamic characteristics and the track irregularity. The two frequency ranges of the track irregularity that have a significant impact on the pantograph-catenary contact were found. Finally, after numerical calculation and analysis, it is recommended to focus on the irregularities with the two wavelength ranges of 9~16 m and 3~4 m in the maintenance.

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34

Zuo, Yan Yan, and Qing Bin Chang. "Simulation Analysis on Passing Curve of Urban Track Vehicle." Advanced Materials Research 308-310 (August 2011): 1956–60. http://dx.doi.org/10.4028/www.scientific.net/amr.308-310.1956.

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In order to study the curve passing performance of urban track vehicle and to evaluate its safety, the calculation model was established and simplified. Then track irregularity was used as input and passing curve was set up. The simulation modal was produced with software SIMPACK. With the track irregularity, the traveling safety of the vehicle was analyzed. The simulation results show that the traveling safety of the track vehicle could satisfy the requirement of relevant standard.

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35

Subarkah, Untung, Hera Widyastuti, and Catur Arif Prastyanto. "Analysis Effect Of Thick Ballast On Track Quality Index (TQI) Value Route Wonokromo – Mojokerto." Jurnal Penelitian Transportasi Darat 23, no. 1 (2021): 30–36. http://dx.doi.org/10.25104/jptd.v23i1.1589.

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In Operational Area 8 Surabaya there are several railway lines, one of which is the Wonokromo - Mojokerto line. This lane has a fairly heavy train traffic frequency including the connecting lane south. This will affect the quality of roads on the Wonokromo - Mojokerto line. To assess damage to a railroad seen from several aspects in the structure of the railroad. These aspects are the structure of the railroad, the structure of the railroad and the geometrical structure of the railroad. In Indonesian railways, the railroad uses railroad geometry consisting of several parameters (track gauge, cant, longitudinal level, and lateral level.) as a basis for assessing railroad quality. In this study will analyze the structure of the railroad under the thickness of the ballast to the Track Quality Index (TQI). In this study using a simple linear regression analysis to determine the variation of the thickness of the ballast to TQI. From the results of the analysis conducted, obtained thickness changes that occur in ballast that affect the value of the Track Quality Index (TQI). Where the greater ballast, the greater the value of TQI.

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36

Wang, Xiao Ping. "Influences of Concrete Creep and Temperature Deformation on Vehilce Travelling across Bridge." Applied Mechanics and Materials 556-562 (May 2014): 655–58. http://dx.doi.org/10.4028/www.scientific.net/amm.556-562.655.

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When long-span pre-stressed concrete bridges are subjected to concrete creep and temperature load , bridge deck deformation will be aroused. Then the additional track irregularity will be generated. It brings about the result that the dynamic response of train-track-bridge system will be influenced. In this paper, with the train-track-bridge coupling vibration theory, a (90+180+90) m continuous beam-arch combination bridge located on a certain passenger line is analysised comparatively, by considering the effect of concrete creep and temperature deformation. The results show that, the track irregularity caused by the concrete creep and temperature deformation influence the wheel unloading rate and the vertical accelararion of the train so obviously with the speed increasing. It can be concluded that the track irregularity need to be considered, especially for high-speed trains.

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37

Zhi-Chen, Wang, Song Ying, and Wang Jian-Xi. "Relation Between Track Irregularity of Speed-Increased Railway and Dynamic Speed Limits Through Simulation." Open Mechanical Engineering Journal 8, no. 1 (2014): 197–200. http://dx.doi.org/10.2174/1874155x01408010197.

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Based on the vehicle-track coupled dynamics theory and the corresponding simulation software ADAMS/Rail software package, a vehicle-track coupling system model is established, and the track irregularity is introduced to the coupling system model as an excitation source. Firstly, the dynamic responses of speed-increased railway vehicle and track components due to different types of track irregularity are obtained. Secondly, the sensitive wavelength of different track irregularities in high-speed operation is discussed. Finally, suggestions about the maximum operation speed to meet the standards value of daily maintenance target, comfortable value, emergency repair and speed management target are put forward.

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38

Resendiz, Esther, John Hart, and Narendra Ahuja. "Automated Visual Inspection of Railroad Tracks." Intelligent Transportation Systems, IEEE Transactions on 14, no. 2 (2013): 751–60. http://dx.doi.org/10.1109/tits.2012.2236555.

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Thousands of miles of railroad track must be inspected twice weekly by a human inspector to maintain safety standards. A computer vision system, consisting of field-acquired video and subsequent analysis, could improve the efficiency of the current methods. Such a system is prototyped, and the following challenges are addressed: the detection, segmentation, and defect assessment of track components whose appearance vary across different tracks and the identification and inspection of special track areas such as track turnouts. An algorithm that utilizes the periodic manner in which track components repeat in an inspection video is developed. Spectral estimation and signal-processing methods are used to provide robust detection of the periodically occurring track components. Results are demonstrated on field-acquired images and video.

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39

Dusza, Mirosław. "Rail vehicle model motion analysis on curved track with vertical irregularity." WUT Journal of Transportation Engineering 130 (September 1, 2020): 75–84. http://dx.doi.org/10.5604/01.3001.0014.5456.

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The properties of a classic railway track largely depend on the properties of the sub-grade, which is most often a natural creation. Atmospheric phenomena (e.g. temperature changes, heavy rainfall) can locally reduce the elasticity of the subgrade and create conditions conducive to permanent track deformation. One of the most common forms of a track fragment destruction is the loss of foundation support (one or several neighbouring sleepers) resulting from the indentation of the ballast material in the subgrade. The pressure of a vehicle passing through a damaged section of the track causes the so-called dynamic track irregularity. The impact of dynamic track vertical irregularity on the values of wheel-rail contact forces of a passing vehicle was investigated. The model of the passenger wagon-track system was created using the VI-Rail tool. The vehicle motion on curves with different values of track radius and superelevations was investigated. Vertical track irregularities occur on the internal rail only. The lengths of the track irregularity correspond to one, two or three sleepers unsupported on one side. The test results are presented in the form of diagrams and referred to applicable standards and regulations.

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40

Lee, Bang-woo, Hyeong-jin Yeom, and Yong-gul Park. "Inspection and Maintenance of Track Irregularity in Concrete Track." Journal of the Korean Society for Railway 21, no. 8 (2018): 774–85. http://dx.doi.org/10.7782/jksr.2018.21.8.774.

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41

Ananthanarayana, N. "Track irregularity limits from consideration of track-vehicle interaction." Mathematical and Computer Modelling 11 (1988): 932–35. http://dx.doi.org/10.1016/0895-7177(88)90630-9.

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42

Juanjuan, Ren, Yang Rongshan, Wang Ping, Dai Feng, and Yan Xiaobo. "Influence of contact loss underneath concrete underlayer on dynamic performance of prefabricated concrete slab track." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 231, no. 3 (2016): 345–58. http://dx.doi.org/10.1177/0954409716630339.

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Contact loss between the concrete underlayer and the subgrade caused by the differential settlement or stiffness of subgrade structure is a common distress, which deteriorates the mechanical properties of the track structure and adversely affects the safety and comfort for the operation on high-speed railway. The objective of this paper is to study the damage mechanism of prefabricated slab track subjected to such contact loss and to propose a critical value for the size of contact loss that would not jeopardize the safety of rail traffic and riding comfort of passengers. Thus, a vibration calculation model for the vertically coupled vehicle-J-slab track-subgrade system is established using finite element method, both of the short-wave irregularity and the German long-wave irregularity were taken into account to calculate the dynamic response of vehicle, track structure and subgrade with different contact loss areas and speeds scenarios. Based on the numerical simulation results, a critical value of contact loss area is proposed. When the actual contact loss area is smaller than the critical value, the welded joint irregularity is the dominant factor in the vehicle dynamic response; however, when the actual contact loss area is larger than the critical value, the track irregularity induced by contact loss under the concrete underlayer becomes the dominant factor. It is suggested that the contact loss area should be controlled under the critical value in order to ease or mitigate the dynamic response of the vehicle and track structure. The numerical simulation indicates the critical contact loss area is about 10 m2 for the short-wave irregularity case and 14 m2 for the long-wave irregularity case, thus it is suggested that the contact loss area underneath the concrete underlayer should not exceed 10 m2, which is consistent with the Swedish standard and the German standard on weak areas of subgrade compaction.

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43

Li, Ji Yang, Lin Ya Liu, and Dong Hua Kou. "Wu Guang High-Speed Rail Track Irregularity Power Spectrum Analysis." Applied Mechanics and Materials 638-640 (September 2014): 1224–28. http://dx.doi.org/10.4028/www.scientific.net/amm.638-640.1224.

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Irregularity is the locomotive and the main excitation source of vibration, is directly related to the smooth running of the train, safety and comfort, is to control the maximum operating speed of the train one of the main factors. The statistic specimen was collected by track geometry inspection car from Wuhan-Guangzhou high-speed rail. Based on the stationarity test of the specimen, Fast Fourier Transform (FFT) method was used to evaluate the spectrum of the whole specimen space. The power spectrum density (PSD) and related functions of track irregularity were obtained by MATLAB program. We analyzed it by comparing the fitting curve of the national speed lines and fitting curve of Qinhuangdao-Shenyang dedicated passenger railway line, by comparison, the Wuhan-Guangzhou high-speed railway track irregularity is much better than the national speed lines and Qinhuangdao-Shenyang dedicated passenger railway line. The parameter values of PSD fitting curve for track irregularity are obtained by the nonlinear curve-fitting algorithm in the least-squares sense, which has referencing value to maintenance high-speed rail.

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44

Ye, Junjie, and Hao Sun. "The Influence of an Integration Time Step on Dynamic Calculation of a Vehicle-Track-Bridge under High-Speed Railway." Mathematics 9, no. 4 (2021): 431. http://dx.doi.org/10.3390/math9040431.

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In order to study the influence of an integration time step on dynamic calculation of a vehicle-track-bridge under high-speed railway, a vehicle-track-bridge (VTB) coupled model is established. The influence of the integration time step on calculation accuracy and calculation stability under different speeds or different track regularity states is studied. The influence of the track irregularity on the integration time step is further analyzed by using the spectral characteristic of sensitive wavelength. According to the results, the disparity among the effect of the integration time step on the calculation accuracy of the VTB coupled model at different speeds is very small. Higher speed requires a smaller integration time step to keep the calculation results stable. The effect of the integration time step on the calculation stability of the maximum vertical acceleration of each component at different speeds is somewhat different, and the mechanism of the effect of the integration time step on the calculation stability of the vehicle-track-bridge coupled system is that corresponding displacement at the integration time step is different. The calculation deviation of the maximum vertical acceleration of the car body, wheel-sets and bridge under the track short wave irregularity state are greatly increased compared with that without track irregularity. The maximum vertical acceleration of wheel-sets, rails, track slabs and the bridge under the track short wave irregularity state all show a significant declining trend. The larger the vibration frequency is, the smaller the range of integration time step is for dynamic calculation.

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45

ISHIKAWA, Tomoyuki, Yosuke TSUBOKAWA, Masashi MIWA, Atsushi SEKINO, and Koichiro ISHII. "Consideration about Relationship by Distance Approximation between Dynamic Track Irregularity Distributions and Static Track Irregularity Distributions." Proceedings of the Transportation and Logistics Conference 2018.27 (2018): 2203. http://dx.doi.org/10.1299/jsmetld.2018.27.2203.

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46

Ma, Tengfei, Yunshui Zheng, Jing Xu, and Jianfa Wang. "Uninsulated Track Circuit Parameter Adjustment and Ballast Resistance Analysis." Journal of Physics: Conference Series 2561, no. 1 (2023): 012019. http://dx.doi.org/10.1088/1742-6596/2561/1/012019.

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Abstract Uninsulated track circuits are increasingly used in railroad signaling equipment, but the external environment dramatically influences operating conditions. Using the relationship between uninsulated track circuits and ballast resistance, an equivalent four-terminal network model of track circuit transmission characteristics is constructed based on uniform transmission line theory to analyze the influence law of ballast resistance on track surface current. It also makes corresponding adjustments to the track circuit parameters to ensure that the track circuit can work reliably in all four different operating conditions to ensure the safety of railroad transportation.

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47

Patil, S. P. "Natural Frequencies of a Railroad Track." Journal of Applied Mechanics 54, no. 2 (1987): 299–304. http://dx.doi.org/10.1115/1.3173011.

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The natural frequency of an infinite railroad track was first determined by Timoshenko as ωR = √k/m, where k is the constant for the massless Winkler foundation and m is the mass per unit length of the rail. The natural frequencies of the track are determined here by modeling the track as a beam resting on a 3-D inertial elastic layer. It is shown that the mass of the supporting foundation has a significant effect on the natural frequencies of a railroad track. Finally, the concept of “added mass” is introduced in order to determine the natural frequency in a desired mode of vibration, by modeling the track as a beam on the massless Winkler foundation and adding the mass of the foundation to the beam.

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48

Zhang, Yuan, Wei Lin, and Ze Ming Wang. "Comparison of Vertical Model and Spatial Model for Vehicle-Track-Bridge Coupling Vibration System." Advanced Materials Research 243-249 (May 2011): 4307–10. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.4307.

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In this paper, models for vertical and spatial coupling vibration of vehicle-track-bridge system are established separately. The track vertical irregularity sample in time domain is established by power spectrum density and taken as the exciting source to analyze the coupling vibration of vehicle-track-bridge system of two models. The advantages and disadvantages and applicability of the vertical vibration model and the spatial vibration model are analyzed by comparing the vertical vibration responses of the two models under excitation with same level of track vertical irregularity.

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49

Gao, Jianmin, Wanming Zhai, and Yi Guo. "Wheel–rail dynamic interaction due to rail weld irregularity in high-speed railways." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 232, no. 1 (2016): 249–61. http://dx.doi.org/10.1177/0954409716664933.

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Rail weld geometry irregularity is one of the main excitation sources for vehicle–track coupled dynamic system, and it has a direct effect on the wheel–rail dynamic interactions, which are responsible further for the wheel–rail noise, railway component damages, and track deteriorations. In many previous studies, the rail weld irregularity was usually modeled as a single or composite concave cosine wave based on field investigations on traditional railway lines or researchers’ experiences. These investigations were mainly concentrated on the maximum value of the rail weld irregularity. However, the geometrical shape was usually ignored. In this paper, a series of rail weld irregularities measured on Beijing–Shanghai high-speed railway passenger-dedicated line in China are presented. Based on the analysis of the measured rail surface geometry in the weld zones, some typical theoretical models of the rail weld irregularity are established. Then, the effectiveness of the established rail weld irregularity models are demonstrated for dynamic evaluation of the rail weld irregularity in high-speed railways by comparison between the wheel–rail dynamic responses excited by the measured and the modeled rail weld irregularities, respectively. Finally, the influences of different rail weld irregularities on the wheel–rail dynamic interactions are investigated using the vehicle–track coupled dynamics model and the established rail weld irregularity models. The results are expected to be capable of providing references for the analysis and evaluation of the rail weld irregularity in high-speed railways.

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50

Zhang, Quan, Qijin Chen, Xiaoji Niu, and Chuang Shi. "Requirement Assessment of the Relative Spatial Accuracy of a Motion-Constrained GNSS/INS in Shortwave Track Irregularity Measurement." Sensors 19, no. 23 (2019): 5296. http://dx.doi.org/10.3390/s19235296.

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Modern railway track health monitoring requires high accuracy measurements to ensure comfort and safety. Although Global Navigation Satellite System/Inertial Navigation System (GNSS/INS) integration has been extended to track geometry measurements to improve the work efficiency, it has been questioned due to its positioning accuracy at the centimeter or millimeter level. We propose the relative spatial accuracy based on the accuracy requirement of track health monitoring. A requirement assessment of the spatial relative accuracy is conducted for shortwave track irregularity measurements based on evaluation indicators and relative accuracy calculations. The threshold values of the relative spatial accuracy that satisfy the constraints of shortwave track irregularity measurements are derived. Motion-constrained GNSS/INS integration is performed to improve the navigation accuracy considering the dynamic characteristics of the track geometry measurement trolley. The results of field tests show that the mean square error and the Allan deviation of the relative position errors of motion-constrained GNSS/INS integration are smaller than 0.67 mm and 0.16 mm, respectively, which indicates that this approach meets the accuracy requirements of shortwave track irregularities, especially vertical irregularities. This work can provide support for the application of GNSS/INS systems in track irregularity measurement.

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Journal articles on the topic 'Irregularity on the railroad track'

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