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Integrated geophysical surveys on railroads in permafrost areas
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作者 A.Ivanov S.Klepikova +2 位作者 M.Shirobokov A.Urusova A.Savin 《Research in Cold and Arid Regions》 CSCD 2013年第5期582-586,共5页
The zones of thawed ground in the permafrost area are most dangerous from engineer-geologist effect point of view. Detection of such zones, as making forecast of their movement is the main task of engineer-geologist s... The zones of thawed ground in the permafrost area are most dangerous from engineer-geologist effect point of view. Detection of such zones, as making forecast of their movement is the main task of engineer-geologist survey been held in railway industry. This paper presents general issues concerning railway construction and operation in permafrost areas. Comprehensive geophysical methods to monitor the development of thawed soils axe considered in detail. The main physical parameters which help define permafrost and thawed soil patches are described. Author of current paper pointed out main factors, allowing predicting potential areas of development of thawed grounds. They offered set non-destructive methods: GPR investigations, seismic survey and elec- tric exploration. Whole sets of geophysical data: electric resistivity, velocity of S-wave and P-wave (and their correlation), allow us with high confidence specify characteristics and state of soil either under the line of road, or near it. At the same time the meth- od allows to predict direction of further development of thawed ground area. 展开更多
关键词 geophysical surveys on railroads ground-penetrating radar geoelectric sounding seismic refraction survey perma- frost thawed soils
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Characterization and impact analysis of freezing and expansion disease of roadbed in seasonal freezing zone: A case of heavy railroads
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作者 Pei Li Yaqian Dong 《Geohazard Mechanics》 2023年第3期218-230,共13页
The freezing and expansion diseases of railroad roadbeds are prevalent in areas that experience seasonal freezing.This study aims to investigate the features of the freezing and expansion mechanism of seasonal frozen ... The freezing and expansion diseases of railroad roadbeds are prevalent in areas that experience seasonal freezing.This study aims to investigate the features of the freezing and expansion mechanism of seasonal frozen railroad roadbeds and the effects of the freezing and expansion diseases on the roadbeds.This article presents a study of the Shuo-Huang Heavy Duty Railway.Initially,on-site monitoring tests were conducted to analyze the roadbed temperature,water content and deformations due to freezing.Through these tests,the pattern of development of the roadbed freezing and swelling was understood,and the effect of this on the vibration response of the roadbed was investigated.Subsequently,load-free freezing tests were performed to investigate the freezing and expansion features of the roadbed.Through on-site monitoring,it has been determined that the seasonal freezing layer is approximately 0.5 m deep.The depth of the frozen expansion on both sides of the road shows clear differences.The frozen and expansion disease significantly amplifies the vibration acceleration of the roadbed,with a tendency towards low-frequency and high-amplitude vibrations.Through indoor testing,we compared the deformation of frozen specimens and their final freeze and expansion rates at different cold-end temperatures and various initial moisture content levels.We find that the initial moisture content has a greater impact on specimen freezing and expansion.The findings in this paper can be used as a reference for researching and addressing roadbed freezing and expansion problems. 展开更多
关键词 Seasonal permafrost zones Heavy railroads Roadbeds Frost heave disease Vibration response
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Technical Feasibility Study of Passenger Rail Service along the West Route between Las Vegas and Los Angeles
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作者 Hualiang (Harry) Teng Boniphace Kutela 《Journal of Transportation Technologies》 2023年第4期746-755,共10页
The study evaluates the feasibility of running passenger train service from Las Vegas, NV on the Union Pacific Railroad (UPRR), to Barstow, on the Burlington Northern Santa Fe (BNSF) track, to Mojave on UPRR track aga... The study evaluates the feasibility of running passenger train service from Las Vegas, NV on the Union Pacific Railroad (UPRR), to Barstow, on the Burlington Northern Santa Fe (BNSF) track, to Mojave on UPRR track again, and to Lancaster connecting Metrolink to their destinations in Southern California. In this study, the railroad infrastructure was inventoried and issues related to running the passenger service were identified. Passenger train operation was evaluated based on the Rail Traffic Controller (RTC) simulation model. The performance measures of passenger trains including travel time, overall delay and average speed are analyzed. The uncertainty in freight flow and its impact on providing the passenger service is addressed by conducting a sensitivity analysis. The conclusion is that the existing railroad infrastructure is sufficient to provide a passenger train service from Las Vegas to Los Angeles. From an operational perspective, the passenger train is not expected to influence freight trains’ performance on the existing railroads. When freight train flows are increased to 50%, the influence of passenger train service on the freight operation is still minimal. This study recommends restoring a platform at the Las Vegas Station. At the Mojave Station, special care should be given on running the passenger trains where there is no direct railroad connection from BNSF to UPRR. Platforms and walkways require construction at the Lancaster Station for transferring passengers between the Metrolink trains and X-Train. Transferring the passenger train at this station involves stopping the train on mainline and coordinating the operations between different railroads. 展开更多
关键词 Passenger Train Service Railroad Operation RTC Simulation Model Train Performance Sensitivity Analysis
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Longitudinal force in continuously welded rail on long-span tied arch continuous bridge carrying multiple tracks 被引量:16
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作者 闫斌 戴公连 +1 位作者 郭文华 徐庆元 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第5期2001-2006,共6页
Considering arch rib, lateral brace, suspender, girder, pier and track position, the model for the interaction between long-span tied arch continuous bridge and multiple tracks was established by using steel-concrete ... Considering arch rib, lateral brace, suspender, girder, pier and track position, the model for the interaction between long-span tied arch continuous bridge and multiple tracks was established by using steel-concrete composite section beam element to simulate concrete-filled steel tube(CFST) arch rib, using the beam element with rigid arm to simulate the prestressed concrete girder and using nonlinear bar element to simulate longitudinal constraint between track and bridge. Taking a(77+3×156.8+77) m tied arch continuous bridge with four tracks on the Harbin-Qiqihar Passenger Dedicated Line as an example, the arrangement of continuously welded rail(CWR) was explored. The longitudinal force in CWR on the tied arch continuous bridge, the pier top horizontal force and torque due to the unbalance load case, were analyzed under the action of temperature, vertical live load, train braking and wind load.Studies show that, it can significantly reduce track displacement to set the track expansion devices at main span arch springing on both sides; the track stress due to arch temperature variation can reach 40.8 MPa; the track stress, pier top horizontal force and torque are related to the number of loaded tracks and train running direction, and the bending force applied to unloaded track is close to the loaded track, while the braking force applied to unloaded track is 1/4 to 1/2 of the loaded track; the longitudinal force of track due to the wind load is up to 12.4 MPa, which should be considered. 展开更多
关键词 railroad bridge long-span bridge tied arch continuous beam continuously welded rail track-bridge interaction
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用于亚洲电网大容量主干线路的电力管道线路(英文) 被引量:2
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作者 Roger Faulkner 《高电压技术》 EI CAS CSCD 北大核心 2011年第11期2857-2865,共9页
Elpipes are polymer-insulated underground HVDC electric pipelines based on metallic conductors.Elpipes use relatively rigid extruded conductors designed for higher capacity and efficiency that are practical for overhe... Elpipes are polymer-insulated underground HVDC electric pipelines based on metallic conductors.Elpipes use relatively rigid extruded conductors designed for higher capacity and efficiency that are practical for overhead power lines.Rigid insulation may be used.In this paper,we discuss the technical trade-offs for elpipes,and application of elpipes linking load centers to remote dispatchable hydro power,energy storage sites,and large dispatchable loads,to achieve load leveling through non-local storage and dispatchable loads,via the HVDC grid.Elpipes with voltage source converters(VSC) enable placing many AC/DC power taps on a single HVDC loop.It is advantageous to build up a continental scale HVDC grid from local loops that tie together 10-20 taps. 展开更多
关键词 elpipe HVDC VSC LCC GIL HTS GRIDS load leveling supergrid trans-siberian railroad
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Systematization of features and requirements for geological survey of railroad subgrades functioning in cold regions 被引量:2
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作者 Aleksey Lanis Denis Razuvaev 《Research in Cold and Arid Regions》 CSCD 2017年第3期205-212,共8页
The operation of a railway track in cold regions results in the premature deformation of subgrade soils caused by significant temperature fluctuations and ecological imbalance.Identification and calculation of the tha... The operation of a railway track in cold regions results in the premature deformation of subgrade soils caused by significant temperature fluctuations and ecological imbalance.Identification and calculation of the thawing degree of permafrost soils,frost heaving of clays,and groundwater flooding require careful engineering and geological surveying.The paper describes the unique,long-standing experience of the university scientists connected with maintaining the Russian EastSiberian and Trans-Baikal Railways'facilities.Specific features of and requirements for the surveying,depending on the geological and climatic conditions,are identified. 展开更多
关键词 RAILROAD SUBGRADE engineering-geological survey permafrost soils Baikal-Amur RAILROAD
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Pendulum systems for harvesting vibration energy from railroad tracks and sleepers during the passage of a high-speed train: A feasibility evaluation 被引量:2
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作者 Franco E.Dotti Mauricio D.Sosa 《Theoretical & Applied Mechanics Letters》 CAS CSCD 2019年第4期229-235,I0005,共8页
We evaluate the feasibility of recovering energy from the vibrations of track and sleepers,during passage of a high-speed train,by means of a pendulum harvester.A simple mathematical model of the parametric pendulum i... We evaluate the feasibility of recovering energy from the vibrations of track and sleepers,during passage of a high-speed train,by means of a pendulum harvester.A simple mathematical model of the parametric pendulum is employed to obtain numerical predictions,while measured data of vibration tests during the passage of a Thalys high-speed train are considered as input forcing.Since a sustained rotation is the most energetic motion of a pendulum,the possibility of achieving such state is evaluated,taking into account the influence of initial conditions,damping and other factors.Numerical simulations show that rotating pendulum harvesters with sufficiently low viscous damping could be able to generate a usable average power on the order of 5–6 W per unit.Considering a modular arrangement of devices,such energy is enough to feed variety of rail-side equipment,as wireless sensors or warning light systems.However,a suitable choice of initial conditions could be a difficult task,leading to the need of a control action. 展开更多
关键词 Energy HARVESTING Parametric PENDULUM RAILROAD safety TRAIN induced vibration
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Roadbed, embankment, tower support and culvert stability problems on permafrost 被引量:1
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作者 V.G.Kondratiev 《Research in Cold and Arid Regions》 CSCD 2013年第4期377-386,共10页
The history of railway and highway construction in permafrost zones in Russia, the United States, Canada, and China spans more than 110 years. Nonetheless, no railway track or highway has yet been built in such area t... The history of railway and highway construction in permafrost zones in Russia, the United States, Canada, and China spans more than 110 years. Nonetheless, no railway track or highway has yet been built in such area that is impervious to deformation caused by subsidence resulting from the thawing of ice-rich subgrade soils. This paper presents data on the roadbed states of the Trans- baikalian and the Baikal-Amur Railways as well as the Russian "AMUR" Chita-Khabarovsk Highway. It also discusses the feasi- bility of roadbed stability maintenance using methods based on the reduction of the mean annual ground temperature and roadbed preservation in a permafrost state by means of the natural cooling and heating factors ratio regulation resulting in a reduction of the heat generation in the roadbed and the adjoining area accompanied by an increase of heat consumption with help of the sun-precipitation protective sheds (awnings), rock covers, dolomite powder (reflective paint), cooling tube and thermosyphons as well as tower supports and corrugated pipe culverts stability. 展开更多
关键词 Baikal-Amur Railroad Transbaikalian Railroad Highway "AMUR" Chita-Khabarovsk PERMAFROST EMBANKMENT roadbed deformation stabilizing treatment measures
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Life Cycle Assessment of Creosote-Treated Wooden Railroad Crossties in the US with Comparisons to Concrete and Plastic Composite Railroad Crossties 被引量:2
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作者 Christopher A. Bolin Stephen T. Smith 《Journal of Transportation Technologies》 2013年第2期149-161,共13页
Creosote-treated wooden railroad crossties have been used for more than a century to support steel rails and to transfer load from the rails to the underlying ballast while keeping the rails at the correct gauge. As t... Creosote-treated wooden railroad crossties have been used for more than a century to support steel rails and to transfer load from the rails to the underlying ballast while keeping the rails at the correct gauge. As transportation engineers look for improved service life and environmental performance in railway systems, alternatives to the creosote-treated wooden crosstie are being considered. This paper compares the cradle-to-grave environmental life cycle assessment (LCA) results of creosote-treated wooden railroad crossties with the primary alternative products: concrete and plastic composite (P/C) crossties. This LCA includes a life cycle inventory (LCI) to catalogue the input and output data from crosstie manufacture, service life, and disposition, and a life cycle impact assessment (LCIA) to evaluate greenhouse gas (GHG) emissions, fossil fuel and water use, and emissions with the potential to cause acidification, smog, ecotoxicity, and eutrophication. Comparisons of the products are made at a functional unit of 1.61 kilometers (1.0 mile) of rail-road track per year. This LCA finds that the manufacture, use, and disposition of creosote-treated wooden railroad crossties offers lower fossil fuel and water use and lesser environmental impacts than competing products manufactured of concrete and P/C. 展开更多
关键词 CREOSOTE Environmental Impact RAILROAD Crossties Life Cycle Assessment (LCA) CONCRETE PLASTIC COMPOSITE
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Suggestion of Maintenance Criteria for Electric Railroad Facilities Based on Fuzzy TOPSIS 被引量:1
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作者 Sunwoo Hwang Joouk Kim +2 位作者 Hagseoung Kim Hyungchul Kim Youngmin Kim 《Computers, Materials & Continua》 SCIE EI 2022年第3期5453-5466,共14页
This paper is on the suggestion of maintenance items for electric railway facility systems.With the recent increase in the use of electric locomotives,the utilization and importance of railroad electrical facility sys... This paper is on the suggestion of maintenance items for electric railway facility systems.With the recent increase in the use of electric locomotives,the utilization and importance of railroad electrical facility systems are also increasing,but the railroad electrical facility system in Korea is rapidly aging.To solve this problem,various methodologies are applied to ensure operational reliability and stability for railroad electrical facility systems,but there is a lack of detailed evaluation criteria for railroad electrical facility system maintenance.Also,maintenance items must be selected in a scientific and systematic method.Therefore,railroad electrical facility systems are selected for study.Design StructureMatrix(DSM)is utilized to establish considerations tailored to the maintenance characteristics,and the Fuzzy-TOPSIS methodology is utilized for determining the maintenance detail evaluation item baseline weights,a multi-criteria decision-making problem.Studies show that degradation,insulation items have the highest weight of 14.63%,and capacity items have the lowest weight of 5.34%.The results of this may be contributed to the underlying research in carrying out maintenance activities to ensure the reliability and safety of railroad electrical facility systems. 展开更多
关键词 Electrical facility system railroad maintenance fuzzy method
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Propagation of vibrations in thawing deep seasonally frozen soils in railway subgrade 被引量:1
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作者 Gennady M.Stoyanovich Viktor V.Pupatenko 《Research in Cold and Arid Regions》 CSCD 2015年第5期534-540,共7页
In this study, in-situ testing results are given, and the analytical relationship of the vibrations' amplitudes inside an em- bankment by the thawing of the subgrade surface of seasonably deep frozen soils is provide... In this study, in-situ testing results are given, and the analytical relationship of the vibrations' amplitudes inside an em- bankment by the thawing of the subgrade surface of seasonably deep frozen soils is provided. The peculiarities of the vi- bration waves' propagation during the springtime thawing of soils compared to those during the summertime period and the correlation of the vibrations with the under-rail basement moduln~ nf ala^tieitv nro dofinod 展开更多
关键词 railroad subgrade vibrational force deep seasonable frost
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Railroad capacity tools and methodologies in the U.S. and Europe 被引量:2
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作者 Hamed Pouryousef Pasi Lautala Thomas White 《Journal of Modern Transportation》 2015年第1期30-42,共13页
A growing demand for passenger and freight transportation, combined with limited capital to expand the United States (U.S.) rail infrastructure, is creating pressure for a more efficient use of the current line capa... A growing demand for passenger and freight transportation, combined with limited capital to expand the United States (U.S.) rail infrastructure, is creating pressure for a more efficient use of the current line capacity. This is further exacerbated by the fact that most passenger rail services operate on corridors that are shared with freight traffic. A capacity analysis is one alternative to address the situation and there are various approaches, tools, and methodologies available for application. As the U.S. continues to develop higher speed passenger services with similar characteristics to those in European shared-use lines, understanding the common methods and tools used on both continents grows in relevance. There has not as yet been a detailed investigation as to how each continent approaches capacity analysis, and whether any benefits could be gained from cross-pollination. This paper utilizes more than 50 past capacity studies from the U.S. and Europe to describe the different railroad capacity defini- tions and approaches, and then categorizes them, based on each approach. The capacity methods are commonly di- vided into analytical and simulation methods, but this paper also introduces a third, "combined simulation- analytical" category. The paper concludes that Europeanrail studies are more unified in terms of capacity, concepts, and techniques, while the U.S. studies represent a greater variation in methods, tools, and objectives. The majority of studies on both continents use either simulation or a combined simulation-analytical approach. However, due to the significant differences between operating philosophy and network characteristics of these two rail systems, European studies tend to use timetable-based simulation tools as opposed to the non-timetable-based tools commonly used in the U.S. rail networks. It was also found that validation of studies against actual operations was not typically completed or was limited to comparisons with a base model. 展开更多
关键词 Railroad capacity - Simulation - Railroadoperation ~ The U.S. and European railway characteristics
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THE ROLE OF RAILROAD IN THE DEVELOPMENT OF THE AMERICAN WEST—Railroad,Migration and Urban Growth
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作者 Lei Wang Michael Latham 《Chinese Geographical Science》 SCIE CSCD 2001年第3期32-41,共10页
This paper explores the role of geographical expansion of railroads,one of the most important Fransporta-tion vehicles,in the history of American west development,analyses its implication on the unprecedented mi grati... This paper explores the role of geographical expansion of railroads,one of the most important Fransporta-tion vehicles,in the history of American west development,analyses its implication on the unprecedented mi gration move-ment and the resulted urbanization i n the west and concludes with the fact that the appropriate interference b y the governm-net,especially in the early period,is vital to regional development pra ctice,because of market failure at t he initial stage,infrastructure constructio n conducted by the government always plays as the first impetus to any regional develop-ment process.Only through this brid ge,can some physical factors,such a s population,be attracted to feed th e back-ward area.As a result,cities grow fa st and the region develops well.The e xperience can be shared by all countr ies.Be-sides reviewing the history of west development in America,focusing on t he relationship between railroads e xpansion and urban growth,which was realized thr ough population migration.Acomparison on the particular pattern of regional develop-ment between U.S and China is made as well at the end.It is noted that despite of the common first impetus,govern-ment subsidies and the common final r esult,urbanization,the path for th e America is bottom-up,whereas that for China is top down,that is to say,developme nt should originate from big cities,then to towns,and finally radiate in to rural ar-eas. 展开更多
关键词 MIGRATION RAILROAD URBAN growth
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Thermal state of ice-rich soils on the Tommot-Yakutsk Railroad right-of-way
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作者 Pavel Skryabin 《Research in Cold and Arid Regions》 CSCD 2014年第4期356-360,共5页
This paper summarizes the results of investigations carried out in the northern section of the Tommot-Yakutsk Railroad in eastern Siberia, underlain by ice-rich permafrost. The ongoing permafrost and geotechnical rese... This paper summarizes the results of investigations carried out in the northern section of the Tommot-Yakutsk Railroad in eastern Siberia, underlain by ice-rich permafrost. The ongoing permafrost and geotechnical research program in support of railroad construction includes assessment of the ground thermal state on the right-of-way and adjacent areas based on long-term field observations using the method of terrain thermal physics. These studies focus on the upper permafrost within the depth of annual temperature variation. In undisturbed areas, inter-annual variability of the ground thermal state shows little response to recent climatic variations. However, forest clearing and surface disturbance during right-of-way construction cause an increase in permafrost temperature, deepening of the active layer, thaw settlement, and water accumulation along the embankment. The active layer is thickest along the sun-exposed left berm and is thinnest along the more shaded right berm. Measures to prevent thaw-related embankment problems are recommended. 展开更多
关键词 RAILROAD right-of-way temperature thaw depth dynamics PERMAFROST
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2018 Railroad Tie Survey
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作者 Stephen T. Smith 《Journal of Transportation Technologies》 2019年第3期276-286,共11页
This article reports results of a survey of railroad tie management conducted by the Association of American Railroads (AAR) reflecting 2017 practices. Similar surveys were previously conducted for 2013 and 2008 pract... This article reports results of a survey of railroad tie management conducted by the Association of American Railroads (AAR) reflecting 2017 practices. Similar surveys were previously conducted for 2013 and 2008 practices. North American railroads purchase approximately 23 million new wood crossties annually. Most ties are used to replace worn ties. Through this survey, the AAR seeks to provide clarity to its member railroads, the regulators, and other interested parties, regarding how the railroads’ tie purchase preferences and used tie management choices have been changing in response to changing technologies and regulations. Technology changes include use of borate preservatives to dual-treat wood ties to provide longer service life in high decay environments, non-wood ties made of concrete or plastic, and energy conversion methods for used ties such as gasification and torrefaction. Passage of the EPA Non-Hazardous Secondary Materials (NHSM) rule in 2011, including updates in 2013, 2016, and 2018, is reducing the potential for recycling used ties as fuel. However, the EPA is also promoting use of biological materials, such as wood, to produce energy without increasing carbon dioxide (CO2) levels in the atmosphere, thus reducing human caused climate change. Purchase and tie management trends are indicated by the survey results. Approximately 95% of all ties purchased are preservative-treated wood. Due to demonstrated longer service life in high decay zones for wood ties that are dual treated with borate and either creosote or copper naphthenate, the fraction of concrete and plastic tie purchases has decreased while the faction of dual treated wood tie purchases has increased. Recycling used ties for energy remains the most common practice, at 66% of ties, but has declined from 81% in 2013. Reuse of ties for other treated wood uses, such as landscape and agricultural type purposes, remains common at approximately 18%. Landfill disposal remains uncommon, but seems to be increasing at 6% of removed ties. The shift away from recycling for energy is thought to result from the both impact of the EPA NHSM rule and the low cost of natural gas. The smaller market tie users, mainly the short line railroads in contrast to the Class 1 railroads, manage far fewer ties per company, but purchase and manage approximately 31% of all ties. The short lines recycle to landscape and agricultural uses at about half the rate of the Class 1s and dispose in landfills at a much higher rate of 76% versus 1.2% for the Class 1s. This difference is thought to result from the economics and availability of local versus distant management options. 展开更多
关键词 CREOSOTE Copper Naphthenate BORATE RAILROAD TIES Crossties
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Secure Interchange Routing
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作者 Mark Hartong Rajni Goel Duminda Wijesekera 《Journal of Transportation Technologies》 2011年第2期21-29,共9页
Locations that connect tracks from different rail-road companies—referred to as interchange points—ex- change crew, locomotives, and their associated consists. Because trains have a single degree of freedom in movem... Locations that connect tracks from different rail-road companies—referred to as interchange points—ex- change crew, locomotives, and their associated consists. Because trains have a single degree of freedom in movement, that is, they can only operate along the tracks, any delay occurring at an interchange point causes cascading delays in connecting tracks. In addition, authentication and authorization that is expected to take place at interchanges in PTC controlled train movement may add extra delays due to mutual authentication between two security domains. In this paper we propose a model that can address safety and security con- cerns and their interrelationships that govern train movement through an interchange point. We show how a profile of safe operations can be computed for operating an interchange point. 展开更多
关键词 RAILROAD ROUTING INTERCHANGE SAFETY and SECURITY
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Scope and Application of the FIFRA Treated Articles Exemption
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作者 Lawrence S. Ebner David A. Webb 《Journal of Transportation Technologies》 2020年第1期16-20,共5页
This paper discusses the U.S. Environmental Agency’s potential improper expansion of its authority under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), the federal pesticide statute, to regulate not... This paper discusses the U.S. Environmental Agency’s potential improper expansion of its authority under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), the federal pesticide statute, to regulate not only the registration, labeling, and use of wood preservatives, but also treated wood products. EPA’s oversight of wood preservatives under FIFRA is extensive. In recent years, despite EPA’s own Treated Articles Exemption, 40 C.F.R. § 152.25(a), EPA has moved toward utilizing wood preservative labeling in a way that could impose restrictions on the end use of treated wood. Wood preservative registrant and user groups should be concerned and vigilant about this trend toward regulation of treated wood. At the same time, they should continue to interact with EPA in a constructive manner, in part to ensure that EPA respects its own regulatory boundary between wood preservatives, such as creosote, and treated wood, such as creosote-treated railroad crossties, which are a key component of the nation’s transportation critical infrastructure. 展开更多
关键词 CREOSOTE WOOD PRESERVATIVE RAILROAD Crossties TREATED WOOD Registered FIFRA TREATED Article EXEMPTION Critical Infrastructure
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Chest Drain Insertion-Made Easy with Gum Bougie
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作者 Sanjeev Arya Shantanu Belwal Puneet Tyagi 《Case Reports in Clinical Medicine》 2019年第10期275-280,共6页
Background: Surgical Chest drain insertion is a lifesaving procedure. It requires skills and experience towards its prompt insertion. Quite often there is delay or failure caused in its insertion due to excessive fat ... Background: Surgical Chest drain insertion is a lifesaving procedure. It requires skills and experience towards its prompt insertion. Quite often there is delay or failure caused in its insertion due to excessive fat and loose skin in the axillary area while using the conventional methods. Numerous guidelines exist advising its safe placement, but mishaps still occur, as reported multiple times, while placing the chest drain. In addition to this, a delay or failure of its successful insertion can lead to disastrous consequences. Case: We would like to share, with fellow readers, a novel technique which we used in placing a surgical chest drain successfully. We used a gum bougie to guide the chest drain into the pleural cavity instead of using metal trocar, stellate or long forceps. Conclusion: By using this method, we experienced that not only it reduced the amount of time taken for the procedure, but it also had positive impact on the ease of insertion without fear of causing damage to internal organs, which ultimately boosted the operator’s confidence. 展开更多
关键词 Surgical Chest Drain INSERTION SELDINGER RAILROAD Gum BOUGIE PNEUMOTHORAX OBESE
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Optimization study of station track utilization in high-speed railroad based on constraints of control in random origin and process
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作者 Yajing Zheng Dekun Zhang 《Railway Sciences》 2024年第3期332-343,共12页
Purpose-The purpose of this paper is to eliminate the fluctuations in train arrival and departure times caused by skewed distributions in interval operation times.These fluctuations arise from random origin and proces... Purpose-The purpose of this paper is to eliminate the fluctuations in train arrival and departure times caused by skewed distributions in interval operation times.These fluctuations arise from random origin and process factors during interval operations and can accumulate over multiple intervals.The aim is to enhance the robustness of high-speed rail station arrival and departure track utilization schemes.Design/methodologylapproach-To achieve this objective,the paper simulates actual train operations,incorporating the fluctuations in interval operation times into the utilization of arrival and departure tracks at the station.The Monte Carlo simulation method is adopted to solve this problem.This approach transforms a nonlinear model,which includes constraints from probability distribution functions and is difficult to solve directly,into a linear programming model that is easier to handle.The method then linearly weights two objectives to optimize the solution.Findings-Through the application of Monte Carlo simulation,the study successfully converts the complex nonlinear model with probability distribution function constraints into a manageable linear programming model.By continuously adjusting the weighting coefficients of the linear objectives,the method is able to optimize the Pareto solution.Notably,this approach does not require extensive scene data to obtain a satisfactory Pareto solution set.Originality/value-The paper contributes to the field by introducing a novel method for optimizing high-speed rail station arrival and departure track utilization in the presence of fluctuations in interval operation times.The use of Monte Carlo simulation to transform the problem into a tractable linear programming model represents a significant advancement.Furthermore,the method's ability to produce satisfactory Pareto solutions without relying on extensive data sets adds to its practical value and applicability in real-world scenarios. 展开更多
关键词 Control in random origin Control in random process High-speed railroad station Arrival and departure track utilization Optimization Paper type Research paper
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Integrated Quay Crane and Yard Truck Schedule Problem in Container Terminals 被引量:30
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作者 曹瑾鑫 史其信 Der-Horng Lee 《Tsinghua Science and Technology》 SCIE EI CAS 2010年第4期467-474,共8页
Quay crane and yard truck scheduling are two important subproblems in container terminal opera- tions which have been studied separately in previous research, This paper proposes a new problem for the integrated quay ... Quay crane and yard truck scheduling are two important subproblems in container terminal opera- tions which have been studied separately in previous research, This paper proposes a new problem for the integrated quay crane and yard truck scheduling for inbound containers. The problem is formulated as a mixed integer programming (MIP) model. Due to the intractability, a genetic algorithm (GA) and a modified Johnson's Rule-based heuristic algorithm (MJRHA) are used for the problem solution. In addition, two closed form lower bounds are given to evaluate the solution accuracy. Computational experiments show that the solution algorithm can efficiently handle the scheduling problem and that the integrated methods are very useful. 展开更多
关键词 Computational efficiency Containers CRANES Dynamic programming Genetic algorithms Heuristic algorithms Port terminals Railroad yards and terminals Trucks
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