Research on Railway Speed-up Scheme Based on Grey Decision Theory

In this paper, the decision-making problem of speed-up scheme for existing high-speed railway is studied. Considering the different running speed of different parts of high-speed railway, the speed-up scheme of existing line is formulated. Taking the factors affecting the decision-making of railway speed-up scheme into consideration, the efficiency, cost and influence are determined as the evaluation indexes, and the grey target decision-making method in grey system theory is selected to evaluate each scheme. In this problem, qualitative analysis can be used for the optimal decision-making of the initial scheme. The corresponding situations under each index are comprehensively considered and sorted. The value is assigned to each qualitative evaluation to form the effect vector of each situation. In the spherical grey target formed by grey target decision method, the optimal scheme can be obtained by comparing the off-target distance of each effect vector corresponding to the scheme. It is proved that the grey target decision-making method can also obtain the optimal scheme through qualitative analysis when it is difficult to make quantitative analysis.

The Influence Evaluation of the Waste Slag Above Tunnel on the Safety of the Structure of the High-Speed Railway Tunnel

A high-speed railway loess tunnel being built is in the Shallow-Buried Section because the construction party violates the design, and the slag discarded at the top of the tunnel is just down-pressing the main line. In order to ensure that the stability of tunnel structure does not affect the safe operation in the later period, a stratum structure model is established based on non-destructive testing and on-site tunnel monitoring measurement. The parameters of surrounding rock are determined by displacement back analysis method, and the influence of waste slag on the safety of tunnel structure is checked by the parameters obtained from back analysis. Through the comparative analysis of the stress of tunnel lining under two working conditions, combined with relevant codes and design documents, it is considered that the slag has a great influence on the stress of tunnel lining structure, but the sectional strength and maximum crack width of eccentrically compressed components of tunnel lining meet the design requirements, and the structure is within the safety range.

Research on Spatial Dependence of Regional Highway Network and Economic Development

In order to simplify the decision-making of highway construction planning, GIS spatial analysis method and mathematical statistics method are combined to establish a mathematical model of the spatial dependence relationship between highway density and economic development indicators. The model can explain 79.8% of the highway development demand in Gansu Province, and has good accuracy and reliability. The model is used to check the density of highway network in the planning year, which can evaluate the adaptability of highway network construction and economic development, so as to simplify the pre-feasibility study of highway engineering.

Study on Rail Short-Wave Irregularity of Speed Increased Tracks

The data obtained from a field test of irregularity of rail surface in Hu-Kun line, a CWR track, is processed by statistical analysis of maximum amplitude and one-third octave analysis. The result shows that the regularities of rail surface in joint areas of CWR track are worse in common. In general, the amplitudes of rail surface irregularities can get beyond 0.5mm/m, which exceed standard values in every wave length ranges, and the maximum of them can reach 15dB. The conditions of rail surface regularities in non-joint areas are better, and the rail surface irregularities from most of the test points are lower than 0.15mm/m, which do not exceed standard values.

Fault Diagnosis for Vehicle on-Board Equipments of High-Speed Railway Based on GA-ANFIS Model

Vehicle on-board equipment is the most important train control equipment in high-speed railways. Due to the low efficiency and accuracy of manual detection, in this paper, we propose an intellectualized fault diagnosis method based on adaptive neuro-fuzzy inference system (ANFIS) network. Firstly, we collect the fault information sheets that are recorded by electrical personnel, using frequency weighting factor and principal component analysis (PCA) to realize the data extraction and dimension reduction; Then, in order to improve the fault diagnosis rate of the model, using genetic algorithm (GA) to optimize the parameters of the ANFIS network; Finally, using the fault data of a high-speed railway line in 2019 to test the model, the optimized ANFIS model can achieve 96% fault diagnosis rate for vehicle on-board equipments, which indicating the method is effective and accurate.

A Research and Application of the Processing Methods of Railway Measurement Based on Self-Mobile Scanning Measurement System

With the gradual improvement of China’s railway net, the opening of international railways as well as the continuous growth of railway operating mileage, the workload of remeasuring railways is increasing. The traditional methods of remeasuring railways can not meet current high-speed and high-density operating conditions anymore in terms of safety, efficiency and quality, so a safer and more efficient measurement method is urgently needed.This thesis integrated various sensors on a self-mobile instrument, such as 3D laser scanner, digital image sensor and GNSS_IMU, designing a set of intelligent and integrated self-mobile scanning measurement system. This thesis proposed region growing segmentation based on the reflection intensity of point cloud. Through the secondary development of CAD, the menu for automatic processing of self-mobile scanning measurement system is designed to realize rail automatic segmentation, extraction of rail top points, fitting of plane parameters of railway line, calculation of curve elements and mileage management.The results show that self-mobile scanning measurement system overcomes the shortcomings of traditional railway measurement to some extent, and realizes intelligent measurement of railways.

Metal Effect on Reliability of Balise Transmission System Antennas

In railway networks, metal objects near the balise transmission system can affect the performance of antennas in the system operating at 27.095 MHz and 4.23 MHz. In this paper, the performance of the antennas in the proximity of steel rails and metal plates are simulated and tested in terms of resonant frequency, magnetic field distribution. The results show that the metal effect is dependent on the distance between the metal and the antenna. They shift the resonant frequency and change the magnetic field distribution. In order to solve the problem, we find that the antennas should keep specified distance with the steel rails. Also, a metal plate is fixed on the back of on-board antenna unit to reduce the sensitivity to metal. These methods increase the robustness and reliability of balise transmission system antennas in railway signalling.

C3+ATO Function Simulation and Verification Analysis Based on Timed Automata

C3+ATO system plays an important role in controlling train operation and its function is related to the safety of train automatic operation. A simulation and verification method based on timed automata is proposed to verify the function of high-speed railway C3+ATO system. The functional requirements in the C3+ATO system specification are extracted and the timed automata models are established and then the timed automata network model is formed. The message sequence charts are generated and system safety, reachability, existence are verified. As a result, the models meet the functional requirements of the system which provide theoretical reference for the subsequent C3+ATO system design and development, test and measurement, practical application and related specification improvement.

The Fast and Continuous Railway Clearance Inspection Algorithm Based on Vehicle LiDAR Point Cloud

Railway clearance inspection is the foundation work to ensure train safety operation. Aiming at the problem of time-consuming and low accuracy of clearance inspection based on vehicle LiDAR point cloud, this paper proposes a fast and continuous railway clearance inspection algorithm. Firstly, the preliminary clearance inspection is completed by constructing the axial alignment bounding box of the clearance polyhedron. Then fine clearance inspection based on the topology relationship between point cloud and polyhedron to provide an accurate judgment. Finally, the clearance distribution information is obtained by Euclidean clustering. Based on three representative datasets, the proposed algorithm is validated, and the experimental results show that the accuracy and efficiency are enhanced by 25.0% and 83.4% responsibly.

Image Filtering Algorithm of Subway Tunnel Cracks Based on Regional Difference

Aiming at the problems of uneven illumination, low contrast and serious noise interference in subway tunnel images, an adaptive median filtering algorithm based on regional differences is proposed to improve noise detection and noise filtering. The algorithm first used the filter window set in advance by the algorithm to detect and determined the noise point by calculating the gray difference in the window. Then it is only filtered by the effective pixels are median-calculated in the template. The result is output as the gray value in the center of the window. Compared with the traditional median, mean and adaptive median filtering algorithms, the proposed new algorithm can effectively filter out noise while reducing the difficulty of subsequent segment recognition.