High Speed Rail: Track Construction Considerations

2011 ◽  
Author(s):  
Blaine O. Peterson
Keyword(s):  
High Speed ◽  
Optimal Solution ◽  
Rolling Stock ◽  
High Speed Rail ◽  
Track Geometry ◽  
Slab Track ◽  
Passenger Rail ◽  
Construction Methods ◽  
Track System ◽  
Ballasted Track

This paper discusses general High Speed Rail (HSR) track geometry, construction and maintenance practices and tolerances. The discussion will reference several key international projects and highlight different construction methods and the track geometry assessments used to establish and ensure serviceability of a typical HSR system. Historically, established tighter tolerances of “Express” HSR (i.e. operating speeds greater than 240 km/h or 150 mph) systems have favored the use of slab track systems over ballasted track systems. Slab track systems offer greater inherent stability while ballasted track systems generally require more frequent track geometry assessments and anomaly-correcting surfacing operations. The decisions related to which system to use for a given application involve numerous considerations discussed only briefly in this paper. In many cases, the optimal solution may include both track forms. Rolling stock considerations and their influence on track infrastructure design are considered beyond the scope of this paper. This paper will focus predominantly on two slab track systems widely used in international HSR projects: the Japanese J-slab track system; and the German Rheda slab track system. The French track system will be referenced as the typical ballasted track HSR design. The practices discussed in this paper generally apply to systems which are either primarily or exclusively passenger rail systems. In the U.S., these types of systems will necessarily exclude the systems the Federal Railway Administration (FRA) refers to as “Emerging” or “Regional” HSR systems which include passenger train traffic to share trackage on, what are otherwise considered, primarily freight lines.

Probabilistic Analysis of Flying Ballast on High-Speed Rail Lines

2017 ◽  
Author(s):  
Jieyi Deng ◽  
Guoqing Jing ◽  
Xiang Liu
Keyword(s):  
Risk Factors ◽  
High Speed ◽  
Safety Concern ◽  
Rolling Stock ◽  
Probabilistic Assessment ◽  
High Speed Train ◽  
Modeling Framework ◽  
High Speed Rail ◽  
Rail Systems ◽  
Ballasted Track

Safety is a top priority for the development of worldwide high-speed rail systems. Ballast flying is a particular safety concern when a high-speed train is traveling above a certain speed on the ballasted track. Displaced ballast particles from the track may cause damages to rolling stock, as well as the track infrastructure and wayside structures close to the sides of way. The objective of this research is to develop a probabilistic modeling framework to estimate the probability of ballast flight on specific segments or routes, accounting for several principal risk factors. Based on the probabilistic assessment, we propose a methodology to quantify the probability of flying ballast under certain scenarios. The methodology can be further developed, ultimately enabling a normative risk assessment for flying ballast risk management.

scholarly journals Moving element analysis of high-speed rail system accounting for hanging sleepers

2018 ◽  
Vol 148 ◽  
pp. 05007 ◽  
Author(s):  
Jian Dai ◽  
Kok Keng Ang ◽  
Dongqi Jiang
Keyword(s):  
Dynamic Response ◽  
High Speed ◽  
High Speed Train ◽  
Train Track ◽  
Element Analysis ◽  
High Speed Rail ◽  
Factors Affecting ◽  
Rail System ◽  
Track System ◽  
Ballasted Track

It is very common in the ballasted track system that sleepers are not well supported by the ballast materials due to the uneven settlement of the ballast under repeated train passage. These unsupported track elements are often termed as hanging sleepers and they can lead to undesirable effects due to increased dynamic response of the train-track system, especially when the speed of the train is high. In this paper, we present a computation scheme in conjunction with the moving element method for the analysis of high-speed train-track dynamics accounting for hanging sleepers. The proposed computational scheme will be first verified by comparison with available analytical results. The dynamic response of a high-speed train traveling on a ballasted track considering unsupported sleepers is next investigated. Various factors affecting the response of the high-speed rail system including the speed of the train, the number of hanging sleepers and the pattern of the hanging sleepers will be examined and discussed.

Key Construction Technology of Track Slab in Turnout Zones on Passenger Dedicated Lines

2010 ◽  
Author(s):  
Yong Zeng ◽  
Xueyi Liu ◽  
Rongshan Yang
Keyword(s):  
Construction Technology ◽  
Track Geometry ◽  
Slab Track ◽  
Construction Methods ◽  
Ballastless Track ◽  
Track System ◽  
Supporting Layer ◽  
Structure Strength ◽  
High Transition ◽  
Strength And Durability

Diverse types of ballastless track have been developed in turnout zones, of which the prefabricated slab track in turnout zones is characterized with simple and fast construction technology and thus can preferably achieve the structure requirements. Slab tracks can be put into use after the track components are installed completely. A high demand is raised to ensure the accuracy of construction because of the complicated structure and force bearing status. This paper mainly shows the structure features, construction technology process and construction methods. Meanwhile, the construction control standards and important matters needed attention are involved too. The prefabricated slab track system in turnout zones is mainly made of turnout components, prefabricated turnout slab, concrete base and so on, which has advantages of lower structural height, stable track geometry status and less maintenance. The transition from turnout zones to section of ballastless track lines can be achieved easily without extra components. Moreover, the turnout slabs are prefabricated indoor so that the structure strength and durability can be guaranteed. At the same time by using the prefabricated slabs, the installation accuracy is improved and the amount of concrete made in site is greatly reduced. The construction of slab track turnouts mainly include construction of frost retarding layer, leveling blanket and supporting layer, rough track laying, accurate adjustment of turnout slabs, and installation of turnouts. More attention should be paid to the construction accuracy and the ability of keeping track geometry in order to achieve the high transition regularity.

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

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

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

Investigation and Mitigation of Differential Movement at Railway Transitions for US High Speed Passenger Rail and Joint Passenger/Freight Corridors

2012 ◽  
Author(s):  
Erol Tutumluer ◽  
Timothy D. Stark ◽  
Debakanta Mishra ◽  
James P. Hyslip
Keyword(s):  
High Speed ◽  
Performance Monitoring ◽  
Research Effort ◽  
Highway Bridges ◽  
High Speed Rail ◽  
Passenger Rail ◽  
Track System ◽  
Differential Movement ◽  
Foundation Type ◽  
The University

As with most highway bridges, railway transitions experience differential movements due to differences in track system stiffness, track damping characteristics, foundation type, ballast settlement from fouling and/or degradation, as well as fill and subgrade settlement. This differential movement is especially problematic for high speed rail infrastructure as the “bump” at the transition is accentuated at high speeds. Identification of different factors contributing towards this differential movement, as well as development of design and maintenance strategies to mitigate the problem is imperative for the safe and economical operation of both freight and passenger rail networks. This paper presents the research framework and preliminary findings from a recently initiated research effort at the University of Illinois at Urbana-Champaign. Aimed at developing design and repair techniques to mitigate differential movement at railway transitions, this research project involves instrumentation, performance monitoring and numerical modeling of new and existing track transitions.

Setting System Wide RAM Targets in Passenger Rail Project Early Development Phase

2015 ◽  
Author(s):  
Ibrahim Muftic ◽  
David Turner ◽  
Steve Lawrence ◽  
Paul Padegimas
Keyword(s):  
High Speed ◽  
Rolling Stock ◽  
High Speed Rail ◽  
Passenger Rail ◽  
Rail System ◽  
Operations And Maintenance ◽  
System Life ◽  
Service Application ◽  
Tools And Techniques ◽  
And Control

New and expanded passenger rail projects must deliver dependable scheduled service with affordable operations and maintenance (O&M) costs. Reliability, Availability, and Maintainability (RAM) characteristics of equipment, facilities, and rolling stock determine the dependability and O&M costs of a rail system. System designers, builders, and operators can achieve suitable RAM characteristics by applying established engineering concepts, methods, tools, and techniques throughout the system life-cycle. Targeting and achieving system-wide RAM characteristics are necessary to assure the quality of service delivered to the customers and control O&M costs. A rail project reaps maximum benefits from applying system-wide RAM assurance processes if the RAM activities begin in an early planning phase, whether for a green field or an upgrade project, a single passenger rail system subsystem or a whole new railroad or rail service. Application of RAM assurance processes early on guide design to ensure RAM requirements are met in support of achieving overall service dependability and costs goals. RAM assurance processes are often applied at the railroad subsystem level such as rolling stock, train control, communications, traction power, and even infrastructure and civil works. Key challenges in the early phases of a project are setting the appropriate system-wide performance indicators and metrics, using on-time performance, O&M cost, and other system-wide indicators; and then apportioning those targets to each railroad subsystem in a suitable metric that is measurable and directly relevant to each subsystem and its provider. Once the rail system is integrated and in operation, further steps must assure that the system as a whole meets the system-wide RAM targets. This paper describes a model and associated processes that establish the needed parameter sets, analyses, and metrics, and provides a case study based on a new high-speed rail project.

scholarly journals Identification of Sleeper Support Conditions Using Mechanical Model Supported Data-Driven Approach

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3609
Author(s):  
Mykola Sysyn ◽  
Michal Przybylowicz ◽  
Olga Nabochenko ◽  
Lei Kou
Keyword(s):  
High Speed ◽  
Experimental Studies ◽  
Dynamic Interaction ◽  
Theoretical Research ◽  
Rolling Stock ◽  
Monitoring Methods ◽  
Beam Dynamic ◽  
Track Geometry ◽  
Data Driven Approach ◽  
Support Conditions

The ballasted track superstructure is characterized by a relative quick deterioration of track geometry due to ballast settlements and the accumulation of sleeper voids. The track zones with the sleeper voids differ from the geometrical irregularities with increased dynamic loading, high vibration, and unfavorable ballast-bed and sleeper contact conditions. This causes the accelerated growth of the inhomogeneous settlements, resulting in maintenance-expensive local instabilities that influence transportation reliability and availability. The recent identification and evaluation of the sleeper support conditions using track-side and on-board monitoring methods can help planning prevention activities to avoid or delay the development of local instabilities such as ballast breakdown, white spots, subgrade defects, etc. The paper presents theoretical and experimental studies that are directed at the development of the methods for sleeper support identification. The distinctive features of the dynamic behavior in the void zone compared to the equivalent geometrical irregularity are identified by numeric simulation using a three-beam dynamic model, taking into account superstructure and rolling stock dynamic interaction. The spectral features in time domain in scalograms and scattergrams are analyzed. Additionally, the theoretical research enabled to determine the similarities and differences of the dynamic interaction from the viewpoint of track-side and on-board measurements. The method of experimental investigation is presented by multipoint track-side measurements of rail-dynamic displacements using high-speed video records and digital imaging correlation (DIC) methods. The method is used to collect the statistical information from different-extent voided zones and the corresponding reference zones without voids. The applied machine learning methods enable the exact recent void identification using the wavelet scattering feature extraction from track-side measurements. A case study of the method application for an on-board measurement shows the moderate results of the recent void identification as well as the potential ways of its improvement.

Narrowing longitudinally coupled prefabricated slab track maintenance duration with field data analysis of slab deformation under high temperature

2021 ◽  
pp. 095440972098626
Author(s):  
Zai-Wei Li ◽  
Xiao-Zhou Liu ◽  
Hong-Yao Lu ◽  
Yue-Lei He
Keyword(s):  
High Temperature ◽  
High Speed ◽  
Ride Comfort ◽  
Cost Effective ◽  
Periodic Variation ◽  
Longitudinal Force ◽  
Distribution Analysis ◽  
High Speed Rail ◽  
Track Maintenance ◽  
Slab Track

The deformation of longitudinally coupled prefabricated slab track (LCPST) due to high temperature may lead to a reduction in ride comfort and safety in high-speed rail (HSR) operation. It is thus critical to understand and track the development of such defects. This study develops an online monitoring system to analyze LCPST deformation at different slab depths under various temperatures. The trackside system, powered by solar energy with STM8L core that is ultra-low in energy consumption, is used to collect data of LCPST deformation and temperature level uninterruptedly. With canonical correlation analysis, it is found that LCPST deformation presents similar periodic variation to yearly temperature fluctuation and large longitudinal force may be generated as heat accumulates in summer, thereby causing track defects. Then the distribution of temperature and deformation data is categorized based on fuzzy c-means clustering. Through the distribution analysis, it is suggested that slab inspection can be shortened to 6 hours, i.e. from 10:00 am to 4:00 pm, reducing 14.3% track inspection workload from the current practice. The price of workload reduction is only a 2% chance of missed detection of slab deformation. The finding of this research can be used to enhance LCPST monitoring efficiency and reduce interruption to HSR operation, which is an essential step in promoting reliable and cost-effective track service.

The Calculation of the Supporting Stress of Track Plate in Ballastless High-Speed Rail Structure

2011 ◽  
Vol 97-98 ◽  
pp. 3-9
Author(s):  
Yang Wang ◽  
Quan Mei Gong ◽  
Mei Fang Li
Keyword(s):  
Stress Distribution ◽  
High Speed ◽  
Design Theory ◽  
Moving Load ◽  
Structure Design ◽  
Track Structure ◽  
Beam Model ◽  
High Speed Rail ◽  
Slab Track ◽  
Ballastless Track

The slab track is a new sort of track structure, which has been widely used in high-speed rail and special line for passenger. However, the ballastless track structure design theory is still not perfect and can not meet the requirements of current high-speed rail and passenger line ballastless track. In this paper, composite beam method is used to calculate the deflection of the track plate and in this way the vertical supporting stress distribution of the track plate can be gotten which set a basis for the follow-up study of the dynamic stress distribution in the subgrade. Slab track plate’s bearing stress under moving load is analyzed through Matlab program. By calculation and analysis, it is found that the deflection of track plate and the rail in the double-point-supported finite beam model refers to the rate of spring coefficient of the fastener and the mortar.The supporting stress of the rail plate is inversely proportional to the supporting stress of the rail. The two boundary conditions of that model ,namely, setting the end of the model in the seams of the track plate or not , have little effect on the results. We can use the supporting stress of the track plates on state 1to get the distribution of the supporting stress in the track plate when bogies pass. Also, when the dynamic load magnification factor is 1.2, the track plate supporting stress of CRST I & CRST II-plate non-ballasted structure is around 40kPa.

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