Ballast Flying DEM Microscopic Analysis and Counteracting Measures

2011 ◽  
Vol 97-98 ◽  
pp. 266-270 ◽  
Author(s):  
Guo Qing Jing ◽  
Liang Gao ◽  
Xiao Lin Sun
Keyword(s):  
Friction Coefficient ◽  
Microscopic Study ◽  
High Speed ◽  
Microscopic Analysis ◽  
Dynamic Force ◽  
High Speed Railway ◽  
Model Method ◽  
Study Results

Ballast flying problems obsess the high speed railway developments, causing damages to the train and deteriorations to the rail. In the paper, DEM is used to conduct ballast flying mechanism microscopic study, results show ballast flying increases with train dynamic force, and decreases with ballast size and friction coefficient, ballast flying counteracting measures are presented, such as ballast bed parameter and ballast glue. In the end, future possible microscopic ballast flying model method is presented by DEM coupled with CFD.

On prospects for the development of high-speed railway lines in Russia

2017 ◽  
pp. 7-14
Author(s):  
Nikolay Bushuyev ◽  
Darina Shulman
Keyword(s):  
Russian Federation ◽  
High Speed ◽  
Network Formation ◽  
Practical Importance ◽  
High Speed Railway ◽  
Complex Approach ◽  
Study Results ◽  
High Speed Trains ◽  
The Russian Federation ◽  
Traffic Organization

Objective: To consider the prospects for the development of high-speed railway lines (VSM) in Russia. To analyze the fundamentals of “Updated program of high-speed railway communication on the territory of the Russian Federation” approved on November, 23rd 2015 by the decision of OAO “RZhD” board meeting and the social board on the issues of high-speed railway communication in Russia. To formulate the specificities of high-speed traffic organization: promising directions of high-speed headings realization before 2030, as well as the stages of their implementation in Russia. Methods: Multiple regression analysis, as well as the method of multi criterial decisions optimization was applied in the study. Results: The analysis of current and perspective headings was carried out, as well as such characteristics as speed and the running time of “Sapsan” high-speed trains and “Allegro”, “Strizh”, “Lastochka” rapid trains. Special attention was paid to the comparison of strategies given in “Updated program of high-speed railway communication on the territory of the Russian Federation” with the main scientific findings stated in VSM network formation part, obtained on the basis of complex approach to the solution of justification of VSM network formation stage-by-stage approach, taking into account multi criterial estimation of cities and regions’ potential and application of mathematical traffic flow model approach as part of basic regional socioeconomic indices of cities and regions, situated in the zones attractive for future VSM construction. Practical importance: The conclusion was made on the necessity to continue exploratory development in the sphere of topology specification research and stage-by-stage formation of the first VSM in Russia.

A High-Speed Railway Data Placement Strategy Based on Cloud Computing

2011 ◽  
Vol 135-136 ◽  
pp. 43-49
Author(s):  
Han Ning Wang ◽  
Wei Xiang Xu ◽  
Chao Long Jia
Keyword(s):  
Cloud Computing ◽  
High Speed ◽  
Data Access ◽  
Interval Mapping ◽  
Data Placement ◽  
Programming Algorithm ◽  
High Speed Railway ◽  
Mapping Algorithm ◽  
Data Intensive ◽  
Study Results

The application of high-speed railway data, which is an important component of China's transportation science data sharing, has embodied the typical characteristics of data-intensive computing. A reasonable and effective data placement strategy is needed to deploy and execute data-intensive applications in the cloud computing environment. Study results of current data placement approaches have been analyzed and compared in this paper. Combining the semi-definite programming algorithm with the dynamic interval mapping algorithm, a hierarchical structure data placement strategy is proposed. The semi-definite programming algorithm is suitable for the placement of files with various replications, ensuring that different replications of a file are placed on different storage devices. And the dynamic interval mapping algorithm could guarantee better self-adaptability of the data storage system. It has been proved both by theoretical analysis and experiment demonstration that a hierarchical data placement strategy could guarantee the self-adaptability, data reliability and high-speed data access for large-scale networks.

Effects of friction-based fixed bearings on seismic performance of high-speed railway simply supported girder bridges and experimental validation

2018 ◽  
Vol 22 (3) ◽  
pp. 687-701 ◽  
Author(s):  
Lizhong Jiang ◽  
Shanshan Cao ◽  
Biao Wei
Keyword(s):  
Friction Coefficient ◽  
Seismic Performance ◽  
High Speed ◽  
Dynamic Test ◽  
Seismic Damage ◽  
Damage State ◽  
High Speed Railway ◽  
Simply Supported ◽  
Girder Bridges ◽  
Seismic Force

This study investigated the seismic performance of simply supported girder bridges with a span length of 32 m. Those bridges were a common part in China’s high-speed railway system and used spherical bearings to connect girders and piers. First, a finite element model of the scaled bridge with a geometrical similarity ratio of 1:8 was established by OpenSees. Second, five seismic damage states of fixed bearings and piers were defined based on the deformation failure criterion. Finally, an incremental dynamic analysis and a pseudo-dynamic test were performed to evaluate the effects of friction-based fixed bearings on the seismic response and damage state of bearings and piers. Results show that the sliding of friction-based fixed bearings effectively restricts the force transmitting between piers and girders, and reduces the seismic damage of piers. Those bearings with a small friction coefficient lead to a large relative displacement between piers and girders, while those bearings with a large friction coefficient cause a large seismic force exceeding the yield load of piers. Therefore, an appropriate friction coefficient of friction-based fixed bearing should be determined to achieve an optimal seismic performance of bridge according to the specific conditions of bridge and ground motion inputs.

Performance-Based Design Research on a Long-Span High-Speed Railway Suspension Bridge

2019 ◽  
Author(s):  
Xiaoguang Liu ◽  
Hui Guo ◽  
Xinxin Zhao ◽  
Pengfei Su ◽  
Mangmang Gao
Keyword(s):  
High Speed ◽  
Rotation Angle ◽  
Suspension Bridge ◽  
Performance Based Design ◽  
Live Load ◽  
Stay Cable ◽  
Expansion Joint ◽  
High Speed Railway ◽  
Track Geometry ◽  
Study Results

<p>A performance-based design (PBD) framework for high-speed railway suspension bridge is proposed from aspects of structural, operational and public requirements. Stiffness indexes are discussed. Results show that target performance shall include stiffness, strength, fatigue, stability, track geometry, train operation performance, human safety and public loss, etc. Case study results of a high-speed railway suspension bridge show that large cable force provide gravity stiffness with the vertical deflection to main span length is 1/488 under static live load. The longitudinal displacement (LD) is restricted to a proper value by arrangement of inclined stay cable at the mid-span and the viscous dampers between pylon and stiffening girder. LD at girder end under the total live load is 261mm. And the longitudinal drift mode shape appears later than symmetrical transverse and vertical bending. The vertical rotation angle at girder end is only 0.77‰ under ZK load (0.8UIC) for passenger-dedicated line by setting auxiliary pier at side span of the bridge. Considering the operational performance, elastic deformation of wind-resistant bearings at girder end shall be restricted to decrease the transverse rotation angle which has the limit value from 1.0‰ to 2.5‰ under different train speed. And the integral design of bridge expansion joint (BEJ) and rail expansion joint (REJ) at girder end is required.</p>

Telecommunication systems and high-speed railway transport networks

2017 ◽  
pp. 28-46
Author(s):  
Andrey Kanayev ◽  
Andrey Pryvalov ◽  
Vladimir Kotov ◽  
Arkadiy Lebedinskiy ◽  
Pavel Plekhanov ◽  
...  
Keyword(s):  
Control System ◽  
Information Security ◽  
Cyber Security ◽  
High Speed ◽  
Telecommunication Networks ◽  
Theory Approach ◽  
Railway Transport ◽  
High Speed Railway ◽  
Study Results ◽  
The Given

Objective: To consider the main approaches to organization of systems and communication networks on high-speed railway transport and provide cyber security on the basis of current international and home practice in the given sphere. Methods: Game-theory approach, hierarchy analysis method as well as topological transformation of stochastic networks were applied in the given study. Results: It was detected that a single realization of organizational and technical measures on cyber security cannot provide strong security from threats of cyber security during a long period of time; the latter is connected with constant development of data infrastructure, modification of methods, as well as the methods of attacks, potential attacker opportunities and other factors. Telecommunication networks’ security (TKS) of OJSC “Russian railways” and high-speed railway lines (VSM) from cyber impact is a systemic problem, for the solution of which fundamental research studies are to be conducted, aimed at the detection of basic patterns of information confrontation and directions of TKS cyber security provision and, subsequently, research and development activities for creating an automated communication control system of OJSC “Russian railways” and VSM, the constituent part of which is a subsystem of TKS information security. It is advisable to create an expert council based at regional transport universities, which provide extensive analysis conduct of systems and means of providing information security offered by the industry, as well as cyber security of OJSC “Russian railways” and VSM critically important systems including TKS. Practical importance: The realization of the suggested approach to OJSC “Russian railways” and VSM cyber security provision will make it possible to form the conditions for safe functioning of elements of information infrastructure, provide the creation, effective functioning and the improvement of cyber security control system, as well as to minimize damage from possible attack attempts.

Numerical simulation of rail surface-initiated rolling contact fatigue in the switch panel of railway turnouts

2020 ◽  
pp. 095440972090997
Author(s):  
Xiaochuan Ma ◽  
Ping Wang ◽  
Jingmang Xu ◽  
Rong Chen ◽  
Linya Liu
Keyword(s):  
Friction Coefficient ◽  
Fatigue Damage ◽  
High Speed ◽  
Interaction Analysis ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Control Measures ◽  
High Speed Railway ◽  
Friction Control

Considering the complex characteristics of the track structure in railway turnouts, it is difficult and also expensive to experimentally study rail damages; therefore, numerical methods are an effective alternative. This study presents a numerical method to simulate rail surface-initiated rolling contact fatigue in the switch panel of railway turnouts. This method includes simulation of the vehicle–turnout wheel–rail dynamic interaction, analysis of the wheel–rail multipoint non-Hertzian rolling contact that considers the relative motion between the switch and stock rails, and calculation of the accumulated rail surface-initiated rolling contact fatigue. The accumulated rail surface-initiated rolling contact fatigue after the vehicles passed a turnout switch panel 80 times (the average number of vehicles running on the Chinese high-speed railway lines per day) in the through route with facing move was simulated based on this procedure. The result showed that the maximum surface-initiated rolling contact fatigue damage of the switch rail and the stock rail was 1.57 × 10−2 and 0.62 × 10−2, respectively. Surface-initiated rolling contact fatigue in the switch rail mainly occurred at the gauge angle, and in the stock rail it mainly occurred at the center of the rail. In addition, the influence of track parameters (rail inclination, track gauge, and friction coefficient) is analyzed. The friction coefficient influenced the rail surface-initiated rolling contact fatigue. When the coefficient exceeded 0.3 in particular, the rail rolling contact fatigue damage increased sharply. Hence, suitable friction control measures should be taken during rail maintenance in order to mitigate the rail surface-initiated rolling contact fatigue damage, e.g. by keeping the wheel–rail friction coefficient below 0.3.

scholarly journals ON EFFICIENT OPERATIONAL CONCEPT OF FUTURE HIGH-SPEED RAILWAY IN THE CZECH REPUBLIC

2016 ◽  
Vol 5 ◽  
pp. 4
Author(s):  
Michal Drábek
Keyword(s):  
Czech Republic ◽  
Travel Time ◽  
Economic Efficiency ◽  
High Speed ◽  
Rolling Stock ◽  
Travel Times ◽  
High Speed Railway ◽  
The Czech Republic ◽  
Study Results ◽  
Operational Concept

The aim of this paper is to elaborate a layout of the first operational concept of Rapid Services with 1 hour system travel time between Praha and Brno. Two basic methods are used – Integrated Periodic Timetable (periodic rendezvous of all services in IPT-nodes) and Operational Concept Economy Approach, as defined below by the author. In this paper, three recent high-speed railway concepts for the future so-called Rapid Services network of the Czech Republic are followed-up. The first one is an operational traffic planning study by Kalcík, Janoš et al. on behalf of Czech Ministry of Transport from 2010. The second one is the high-speed railway promoting book High Speed Rail Even in the Czech Republic by Šlegr et al. from 2012, with likely the most detailed concept of Rapid Services network. The third one is a paper on progress of the official spatial-technical studies for some future Czech high-speed lines by Šulc from 2014. The importance of achievement of 1 hour travel time between the largest agglomerations is briefly presented. The presented methodological approach, although soft and manager-oriented, comprises some firm principles: segmentation of high-speed train offer, so that more expensive rolling stock is not wasted by operation on long conventional line sections, consideration of system travel times for efficient rolling stock circuit, restriction of need for links from high-speed to conventional lines, and utilization of high-speed lines as a "rail highway". This approach is intended to be particularized iteratively, with every application. So, in this paper, first version of Operational Concept Economy Approach is introduced. The key idea is that passengers should be offered such travel times and service intervals (headways) and such number of direct services, which are adequate to their potential demand, but as much synergistic effect as possible should be strived to be achieved for every proposed construction (new or modernized one). Such approach goes towards economic efficiency, which is crucial indicator for political decision necessary for building, let alone EU co-funding of the construction. Experience shows that in many Czech feasibility studies, achievement of sufficient economic efficiency was the most complicated part of the study. Results show that an efficient operational concept can be designed not at the expense of runtimes between the largest cities.

Effects of Ni-Coated Graphite Flake on Braking Behavior of Cu-Based Brake Pads Applied in High-Speed Railway Trains

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Peng Zhang ◽  
Lin Zhang ◽  
Kangxi Fu ◽  
Peifang Wu ◽  
Jingwu Cao ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
High Speed ◽  
Maximum Temperature ◽  
Graphite Flake ◽  
Wear Loss ◽  
Linear Wear ◽  
High Speed Railway ◽  
Brake Pads ◽  
The Mean ◽  
Braking Process

Cu-based brake pads applied in high-speed railway trains containing Ni-coated graphite flake and uncoated graphite flake were fabricated by powder metallurgy. The braking properties of the brake pads were investigated by a scaled down testing apparatus with the pad-on-disk configuration under various braking speeds and braking pressures. Compared with the brake pads containing uncoated graphite flake (designated GF), the brake pads containing Ni-coated graphite flake (designated NGF) exhibits a similar braking performance at lower braking speed and pressure. However, NGF shows more stable friction coefficient, lower linear wear loss, and lower maximum temperature during the braking process at worse braking conditions, e.g., 350 km/h, 1.5 MPa. The Ni-coating on the surface of Ni-coated graphite can transfer the mechanical bonding between copper and graphite to diffusion bonding so that there is a stronger interface bonding between copper and Ni-coated graphite. Further, the multiple linear regression analyses reveal that the mean friction coefficient of NGF is more sensitive to braking pressure than braking speed because of the better thermal resistance of NGF, while the mean friction coefficient of GF and the linear wear loss are mainly affected by braking speed.

Study of Traffic Accessibility in Poyang Lake Economic Zone Oriented by High-Speed Railway

2012 ◽  
Vol 178-181 ◽  
pp. 1778-1781
Author(s):  
Hong Yan Yin
Keyword(s):  
High Speed ◽  
Spatial Organization ◽  
Poyang Lake ◽  
Spatial Effects ◽  
High Speed Rail ◽  
High Speed Railway ◽  
Hub And Spoke ◽  
Study Results ◽  
Economic Zone ◽  
Traffic Organization

The high-speed railway framework can promote the harmonious development in the unbalanced regions. Based on construction experiences and spatial development of high-speed railway, the spatial effects were analyzed in traffic economic belt, regional balance, spatial organization reconfiguration and urban environment improvement. According to the high-speed rail plan of China, the traffic accessibility of spatial organization in Poyang lake economic zone were discussed in internal traffic accessibility and external traffic accessibility. The study results showed that the hub-and-spoke patterns of the spatial traffic organization reconfiguration in Poyang Lake agglomeration can realize the regional balance oriented by the high-speed railway. The patterns can be also applied to other underdeveloped and unbalanced regions.

Concrete Crack Control in Monolithic Concrete Bed Construction of High-Speed Railway in Northwest Area of China

2013 ◽  
Vol 405-408 ◽  
pp. 3081-3085
Author(s):  
Xian Xi Tang ◽  
Yan Peng Zhu ◽  
Xian Zhou Tang ◽  
Wei Guo
Keyword(s):  
High Speed ◽  
Control Measures ◽  
Specific Situation ◽  
Construction Technology ◽  
High Speed Railway ◽  
Mixture Ratio ◽  
Crack Control ◽  
Concrete Crack ◽  
Cracking Control ◽  
Study Results

There were some reasons which cause the concrete cracks in monolithic concrete bed construction of high-speed railway. In this paper, combined with the specific situation of monolithic concrete bed construction of high-speed railway in northwest area of China, the states and causes of two kinds of cracks in monolithic concrete bed of high-speed railway were analyzed, the concrete cracking control measures were discussed from the concrete mixture ratio, construction technology and maintenance measures and other aspects, and the corresponding views were put forward. The study results had the important guiding significance on crack controls of concrete structure during the construction process of northwest area.

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