2019 Joint Rail Conference最新文献

{"title":"High Speed Intercity and Urban Passenger Transport Maglev Train Technology Review: A Technical and Operational Assessment","authors":"Fábio C. Barbosa","doi":"10.1115/JRC2019-1227","DOIUrl":"https://doi.org/10.1115/JRC2019-1227","url":null,"abstract":"Magnetic levitation (maglev) is a highly advanced technology which provides, through magnetic forces, contactless movement with no wear and friction and, hence, improved efficiency, followed by reduced operational costs. It can be used in many fields, from wind turbines to nuclear energy and elevators, among others. Maglev trains, which use magnetic levitation, guidance and propulsion systems, with no wheels, axles and transmission, are one of the most important application of the maglev concept, and represents the first fundamental innovation of rail technology since the launch of the railroad era. Due to its functional features, which replaces mechanical components by a wear free concept, maglev is able to overcome some of the technical restrictions of steel-wheel on rail (SWR) technology, running smoother and somewhat quieter than wheeled systems, with the potential for higher speeds, acceleration & braking rates and unaffected by weather, which ultimately makes it attractive for both high speed intercity and low speed urban transport applications. From a technical perspective, maglev transport might rely on basically 3 technological concepts: i) electromanetic suspension (EMS), based on the attraction effect of electromagnets on the vehicle body, that are attracted to the iron reactive rails (with small gaps and an unstable process that requires a refined control system); ii) Electrodynamic Levitation (EDL), which levitates the train with repulsive forces generated from the induced currents, resulted from the temporal variation of a magnetic field in the conductive guide ways and iii) Superconducting Levitation (SML), based on the so called Meissner Effect of superconductor materials. Each of these technologies present distinct maturity and specific technical features, in terms of complexity, performance and costs, and the one that best fits will depend on the required operational features of a maglev system (mainly speed). A short distance maglev shuttle first operated commercially for 11 years (1984 to 1995) connecting Birmingham (UK) airport to the the city train station. Then, high-speed full size prototype maglev systems have been demonstrated in Japan (EDL) (552 kph - 343 mph), and Germany (EMS) (450 kph - 280 mph). In 2004, China has launched a commercial high speed service (based on the German EMS technology), connecting the Pudong International Airport to the outskirts of the city of Shanghai. Japan has launched a low speed (up to 100 kph - 62.5 mph) commercial urban EMS maglev service (LIMINO, in 2005), followed by Korea (Incheon, in 2016) and China (Changsha, in 2016). Moreover, Japan is working on the high speed Maglev concept, with the so called Chuo Shinkansen Project, to connect Tokio to Nagoya, in 2027, with top speeds of 500 kph (310 mph). China is also working on a high speed maglev concept (600 kph - 375 mph), supported on EMS Maglev technology. Urban Maglev concept seeks to link large cities, with their satellite towns and","PeriodicalId":287025,"journal":{"name":"2019 Joint Rail Conference","volume":"56 49","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131603677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and Strength Evaluation of Laser-Welded Carbody for Railway Vehicles","authors":"Qi Luo, Chunyu Zhang, Ziwen Fang, Kefei Wang, Jianran Wang, Haifeng Hong, Hongxiao Wang, S. Kirkpatrick","doi":"10.1115/JRC2019-1222","DOIUrl":"https://doi.org/10.1115/JRC2019-1222","url":null,"abstract":"Laser welding has received increased interest in the rail industry due to its outstanding performance in aesthetics, strength, heat affected area, precise control and sealing. This paper introduces the laser-welded stainless steel carbody used in subway cars. The carbody structure, welding methods, strength and fatigue analysis methods, and test verification and validation results are discussed. Firstly, the shear strength of laser welding on stainless steel with different thickness combinations were obtained through tests. The preliminary carbody structure was designed based on the material and welding properties. Then the finite element analysis (FEA) was conducted on the preliminary design to evaluate the strength and optimize the structure. After the optimization was completed, a full-size car was manufactured, and the strength test was performed. In the process of FEA and strength evaluation, the simulation accuracy of different element types and the influence of loading force directions have been considered. Based on the design, simulation and test data, a complete laser welding carbody strength evaluation system was established, which can provide valuable reference for researchers and engineers in the rail vehicle industry. The entire design, analysis and testing process complies with ASME-RT2-2014 and this is also one of the first to implement this standard.","PeriodicalId":287025,"journal":{"name":"2019 Joint Rail Conference","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124891536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of Reduced Share of Rotary Frequency Converters in a Low Frequency Synchronous Railway Grid: A Transient Stability Study","authors":"J. Laury, Lars Abrahamsson, M. Bollen","doi":"10.1115/JRC2019-1238","DOIUrl":"https://doi.org/10.1115/JRC2019-1238","url":null,"abstract":"Most low-frequency AC single-phase railway grids have both power-electronic based Static Frequency Converters (SFCs) and electrical-machine based Rotary Frequency Converters (RFCs) connecting them to the three-phase public grid.\u0000 Already today, in some such grids, a majority of the power conversion is from SFCs. As railway traffic (and thus power demand) increases, more SFCs are installed for capacity increase, while the number of RFCs remains (almost) constant. Thus, the share of SFCs is expected to increase, and the ratio of installed rotational inertia over installed power to decrease.\u0000 This paper investigates how different shares of SFCs affect the transient stability of low-frequency AC railway grids when having a mix of RFCs and SFCs converting three-phase AC power to single-phase AC power. Results from numerical simulations of the interactions that occur between converters when and after the grid is subject to a fault are presented.\u0000 The numerical studies show that with an increased share of SFCs there is an increased oscillatory behavior, for example in the voltage magnitude and active power after fault clearance.","PeriodicalId":287025,"journal":{"name":"2019 Joint Rail Conference","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114815956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"U.S. Freight Rail Fuel Efficiency: 1920-2015 Review and Discussion of Future Trends","authors":"M. Iden","doi":"10.1115/JRC2019-1296","DOIUrl":"https://doi.org/10.1115/JRC2019-1296","url":null,"abstract":"U.S. freight railroads produce about 40 percent of freight gross ton-miles while consuming only about 1/20th of the total U.S. diesel fuel1. Compared to heavy-duty trucks, freight railroads have significant energy (and emissions) advantages including the low coefficient of friction of steel wheel-on-rail (compared to rubber tires-on-pavement) and multiple-vehicle trains. However, improved heavy-duty truck technologies are being federally-funded and developed which may create some challenges to freight rail’s long-standing environmental (and economic) advantage in certain transportation markets and corridors.\u0000 This paper reviews U.S. freight rail fuel efficiency (measured in gallons of fuel per thousand gross ton-miles) from 1920 to 2015, using published records from the former Interstate Commerce Commission (ICC) archived and made available by the Association of American Railroads (AAR). All freight locomotive energy consumption (all types of coal, crude oil, electricity kilowatt-hours and diesel fuel) are converted into approximations of diesel gallons equivalent based on the nominal energy content of each locomotive energy type, in order to show the effect of transitioning from steam propulsion to diesel-electric prior to 1960 and the application of other new technologies after World War II. Gross ton-miles (rail transportation work performed) will similarly be tracked from historic ICC and AAR records. Annual U.S. freight rail fuel efficiency is calculated and plotted by dividing total calculated diesel gallons equivalent (DGe) consumed by gross (and by lading-only net) ton-miles produced.\u0000 New technologies introduced since 1950 which have likely contributed to improvements in freight rail fuel efficiency (such as introduction of unit coal trains, distributed power, alternating current locomotives, etc) will also be discussed and assessed as to relative contribution to fuel efficiency improvements.\u0000 The paper includes a discussion about U.S. freight rail fuel efficiency compared to heavy-duty truck fuel efficiency, with comments on projected improvements in heavy-duty truck technologies and fuel efficiency. A conclusion is that U.S. freight railroads and equipment suppliers need to be more aware of projected heavy-duty truck fuel efficiency improvements and their potential for erosion of some aspects of traditional railroad competitiveness. Numerous suggested action plans are discussed, with particular focus on reducing the aerodynamic drag (a delta velocity-squared factor in train resistance and power requirement) of double-stack container trains.\u0000 Last, this paper discusses possible courses of action for U.S. freight railroads to achieve fuel efficiency improvements greater than the historic ∼1 percent improvement achieved over the past 50 years. If freight rail is to remain economically competitive vis a vis heavy duty trucking, railroads will have to identify, evaluate and implement new technologies and/or new operating practices which can","PeriodicalId":287025,"journal":{"name":"2019 Joint Rail Conference","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121207430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Safety and Security Analysis for Movable Railroad Bridges","authors":"Yongxin Wang, Matthew Jablonski, Chaitanya Yavvari, Zezhou Wang, Xiang Liu, Keith Holt, D. Wijesekera","doi":"10.1115/JRC2019-1251","DOIUrl":"https://doi.org/10.1115/JRC2019-1251","url":null,"abstract":"Movable railroad bridges, consisting of lift, bascule, or swing bridges have been used by American rail tracks that cross usable waterways for over a century. Although custom made, movable bridges share many common components and designs. Most of them use weight bearing towers for the movable span using electric or electro-hydraulic systems lift and/or rotate these movable spans. Automated locks hold the bridge in place as soon as the movement stops. The bridge operation, train and ship signaling systems work in synchrony for trains and waterway traffic to be granted safe passage with minimal delay. This synchrony is maintained by using custom-made control systems using Programmable Logic Controllers (PLCs) or Field Programmable Gate Arrays (FPGAs). Controllers located on the movable and the static parts of the bridge communicate using radio and/or wired underwater links sometimes involving marine cables.\u0000 The primary objective of this paper is to develop a framework to analyze the safety and security of the bridge operating systems and their synchronous operations with railway and waterway systems. We do so by modeling the movable physical components and their control system with the interconnected network system and determine the faults and attacks that may affect their operations. Given the prevalence of attacks against PLCs, FPGAs and controllers, we show a generic way to determine the effect of what if scenarios that may arise due to attacks combined with failures using a case study of a swing bridge.","PeriodicalId":287025,"journal":{"name":"2019 Joint Rail Conference","volume":"37 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129942783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fuel Cell Rail Technology Review: A Tool for an Autonomous Rail Electrifying Strategy","authors":"Fábio C. Barbosa","doi":"10.1115/JRC2019-1223","DOIUrl":"https://doi.org/10.1115/JRC2019-1223","url":null,"abstract":"Rail (passenger and freight) industry has been under pressure to tackle climate change, local and noise emissions. The current available powertrain technologies to reach the reduced greenhouse (GHG) and zero local emissions demands are electric (fed from the power grid), battery and fuel cell.\u0000 However, the associated infrastructure costs (electrical equipments and the required overhead catenary infrastructure) have limited the electric option to heavy loaded corridors. Battery electric powered rail vehicles could be another potential option, but their system recharging requirements might significantly limit the system’s availability, thus, impacting the rail vehicle’s on-the-job performance.\u0000 The recent breakthrough of fuel cell technology in the heavy duty road industry (mainly transit buses), allied with its operational flexibility and environmental performance has opened the way for this groundbreaking technology in the rail industry.\u0000 Fuel cells generate electricity onboard, using hydrogen or hydrogen rich hydrocarbon fuels. Electricity is, then, stored in batteries or fed directly into a rail vehicle’s high voltage propulsion system.\u0000 From an operational perspective, fuel cell powered rail vehicles might replace diesel ones in a one-to-one relationship, with the same range and running times, and a more efficient and less noisy powertrain. Moreover, the on-site refilling station is the only additional infrastructure element required, compared to diesel rail vehicle baselines. In short, fuel cell technology might offer a long term local zero emission alternative, fast refuelling (like diesel), flexibility, with self-electrification, integration with a renewable energy source and a quiet operation.\u0000 Given their outstanding operational and environmental features, several rail market niches might be addressed by the fuel cell technology: i) light rail and trams in urban environments; ii) commuter and regional trains operating on non electrified tracks; iii) shunt or switch locomotives in rail yards (generally located on central portions of large cities or at the crossroads of major rail distribution hubs); iv) underground mining locomotives, and v) line haul locomotives.\u0000 Since 2002, there has been an intense activity in the global development of fuel cell technology for the rail industry for both passenger and freight markets.\u0000 This work is supposed to present, based on the compilation of information from a multitude of acknowledged sources, a review of fuel cell rail technology, followed by an overview of fuel cell rail experiences and feasibility studies, highlighting their main outcomes, as well as fuel cell technology potential to offer lower operational costs (fuel and maintenance) and improved performance for the rail industry.","PeriodicalId":287025,"journal":{"name":"2019 Joint Rail Conference","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128474626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Milwaukee Streetcar Overhead Contact System: A Challenging Design Effort","authors":"Paul F. White, Gerti Kola","doi":"10.1115/JRC2019-1294","DOIUrl":"https://doi.org/10.1115/JRC2019-1294","url":null,"abstract":"The new Milwaukee Streetcar system has been in the planning, design and construction phases for over 10 years and on November 2, 2018, operations with a combined overhead contact system and streetcar battery power commenced ushering in a new era of growth for the City of Milwaukee. Many challenges in the design and construction of the overhead contact line and power system were encountered during this time period including budgetary constraints, multiple pole location changes, underground obstacles, low clearance bridges, alignment changes, utility conflicts, and changing vehicle requirements.\u0000 The line was originally designed for pantograph operation but soon adapted for pole/pantograph current collection and then changed back to pantograph only current collection during the final design. The original design consisted of underground feeder cables to supplement a 4/0 contact wire but eventually not utilized due to budgetary constraints. Instead, a larger 350 kcmil contact wire was used with no paralleling feeder cables. The added weight of a 350 kcmil wire with wind, ice and low temperatures created high forces in the overhead contact system (OCS) leading to challenges in pole and foundation design where compliance to the National Electrical Safety Code (NESC) was required.\u0000 The OCS style originally proposed and finally constructed used an inclined pendulum suspension (IPS) system that was constant tensioned with rotating springs deemed by the installing contractor superior to balance weights. The pendulum system was chosen as it is simple, lightweight, less visually obtrusive, and more economical than other suspension systems such as stitch and steady arm that are being used on other streetcar or light rail systems. IPS has provided Milwaukee with an excellent operating overhead contact system.\u0000 Buildings along the route that were not historic structures were utilized where possible for span wire attachment but in many locations long bracket arms up to 40 feet long had to be used requiring special designs to keep the size of the pipes standard with the rest of the system. Challenges arose at low bridge underpasses where the contact wire had to be below required code height and special precautions had to be undertaken. Other areas such as the St. Paul Lift Bridge proved challenging as well where special electrically interlocked OCS devices were initially designed to de-energize the overhead wires and is further discussed with the reasoning for their use.\u0000 This paper outlines the phases of design, the changes to the design that occurred over time, the challenges encountered to the OCS design, the method of design, and the final disposition of the design for construction. It further outlines the construction of the system and problems encountered with poles, foundations, bracket arms, traction power substations, contact wire, feeder cables, and winter conditions affecting the integrity of these structures and how some of these problems were solved.","PeriodicalId":287025,"journal":{"name":"2019 Joint Rail Conference","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114305659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Boundary Conditions Effects on the Crack Growth Mechanism Under Cycling Bending","authors":"G. Pucillo, L. Esposito, D. Leonetti","doi":"10.1115/JRC2019-1274","DOIUrl":"https://doi.org/10.1115/JRC2019-1274","url":null,"abstract":"The recent increase of train speed and frequency determines a rise of the loads transmitted to the superstructure. Therefore, railway components might experience service loads that have not considered at the design stage. Moreover, wear and backlash modification between components of a mechanical system might be able to modify the internal boundary conditions of the assembly. According to damage tolerance philosophy, an initial flaw is assumed to exist in the fatigue critical location of a structural component, and the analysis of the crack propagation life for such component needs accurate Stress Intensity Factor (SIF) evaluations.\u0000 In this study, the effects of the boundary conditions on the crack propagation life have been evaluated for a semi-elliptical surface crack having semi-axes a and c and growing from the root of a shoulder fillet notch in a round bar loaded in bending. Two cases have been analyzed: - the shoulder is free from external forces; - the shoulder is in contact with an adjacent generic body.\u0000 At first, the SIF distribution has been calculated with the Virtual Crack Closure Technique, considering or not the nonlinear effect induced by the contact forces arising from the interaction between the shoulder and the neighboring component. Successively, in both the above cases a two-parameters propagation law has been utilized to predict the evolution of both crack shape and crack depth when a cyclic bending load is applied to the rod. For this purpose, different values of the Stress Concentration Factor at the root of the fillet, and of the initial aspect ratio of the crack front, were considered in the calculations.\u0000 It is found that the aspect ratio evolves to a unique asymptote, taking or not into account the non-linearity introduced by the contact at the shoulder, and this value depends on the notch severity.\u0000 The ratio between the dimensionless SIFs obtained with and without the unilateral constraint at the shoulder, βcs / βfs, does not depend on the relative crack depth and crack shape. Also, the effect of the notch severity on the dimensionless SIF appears to be evident only for the portion of the crack front in the vicinity of the free surface.","PeriodicalId":287025,"journal":{"name":"2019 Joint Rail Conference","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132883710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cyber Security Analysis for Advanced Train Control System (ATCS) in CTC Systems: Concepts and Methods","authors":"Zezhou Wang, Xiang Liu, Yongxin Wang, Chaitanya Yavvari, Matthew Jablonski, D. Wijesekera, B. Sykes, Keith Holt","doi":"10.1115/JRC2019-1236","DOIUrl":"https://doi.org/10.1115/JRC2019-1236","url":null,"abstract":"Advanced Train Control System (ATCS) is a proprietary network protocol that expands the functionality and efficiency of Centralized Traffic Control (CTC) systems, by using radio communications (radio code line) for message delivery. However, end-to-end cyber security issues were not considered during initial design of ATCS in the 1980s. Meanwhile, the landscape of cyber-physical threats and vulnerabilities has changed dramatically over the last three decades. Even though cutting-edge systems like Positive Train Control (PTC) have adopted security properties such as integrity check and encryption methods, major railroads in North America still deploy legacy ATCS standards to maintain their individual CTC system.\u0000 This paper first illustrated the background and general specifications of ATCS applications in North American railroads. The research team has noticed that few studies have systematically analyzed this topic since the emergence of ATCS, though its applications are still prevailing in the industry. Divided by both vital and non-vital operational scenarios, this paper presented case studies for ATCS-related vulnerabilities. We used a sender-receiver sequencing-based analysis and proposed a consequence-based simulation model to identify and further evaluate the cyber and physical risks under potential cyber-attacks. For the identified risk, the paper evaluated the likelihood based on the practical operational sequences, and recommended potential countermeasures for the industry to improve the security over the specific case. The research concluded that the fail-safe design in the ATCS systems would prevent the exploiting known security vulnerabilities which could result in unsafe train movements. However, the service disruptions under certain speculated attacks need further evaluation. At the end of this paper, we discussed our ongoing work for disruption evaluation in the wake of successful cyber attacks.","PeriodicalId":287025,"journal":{"name":"2019 Joint Rail Conference","volume":"216 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123029374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Train-Induced Load Effects on the Thermal Track Buckling","authors":"G. Pucillo","doi":"10.1115/JRC2019-1276","DOIUrl":"https://doi.org/10.1115/JRC2019-1276","url":null,"abstract":"Thermal track buckling is probably the major problem due to the advent of continuous welded rail track. In fact, when the rails temperature rises over a critical value, the track can buckle, suddenly or progressively, in the lateral plane. Both poor ballast conditions and large lateral alignment defects are the principal causes of such phenomenon.\u0000 In a previous paper, a parametric finite element model for thermal track buckling simulation was presented and validated by comparison with analytical results of the literature. In this study, the finite element model has been further validated by comparison with analytical and numerical results obtained by three other authors.\u0000 Moreover, to take into account the effect on the buckling temperatures of the vertical loads due to train passes, the tie-ballast lateral resistance has been modified along the track, taking into account the vertical reaction forces distribution induced by axle loads.\u0000 A sensitivity analysis has been carried out both for tangent and curved track, considering two values of the alignment defect amplitude, and different values of the parameters that characterize actual railway vehicles.\u0000 It is found that the conditions to trigger progressive buckling (△Tmax ≈ △Tmin) are attained with small values of the truck center distance, and in a more accentuated manner in the presence of high values of the lateral alignment defect.\u0000 △Tmax and △Tmin increase with axle spacing, and this increase is more pronounced for low values of the truck center spacing. △Tmax and △Tmin also increase with curve radius, but decrease for increasing values of the misalignment defect amplitude.\u0000 In explosive buckling conditions (△Tmax ≠ △Tmin), there is a limit value of the truck center distance above which the vertical load has no more effects, and the results of the static thermal buckling are found.","PeriodicalId":287025,"journal":{"name":"2019 Joint Rail Conference","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125940087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}