Rail Traffic Research Articles

Research on Quick Superplastic Forming Technology of Industrial Aluminum Alloys for Rail Traffic

Quick superplastic forming is a new technology, which combines hot drawing preforming and superplastic forming. It makes full use of the high speed of hot drawing and good formability of superplasticity. For aluminum alloy complex components, the difficulties of stamping and low speed of superplasticity be perfect solved. In this work, the best forming process of side wall outer panel of metro vehicle was determined by forming experiment using quick superplastic forming technology. The high-speed rail edge skin with a very small fillet shape (R≤4 mm) and the large-size subway door frame part (h≈80 mm) formed by straight wall deep drawing were manufactured, using industrial aluminum alloy sheet with thickness of 4 mm. Meanwhile, the formed parts show the advantages of high dimensional accuracy and uniform wall thickness distribution, and the mechanical properties of formed parts can completely meet the requirements as well, which demonstrates the desirable efficiency, low cost and feasibility of this new technology.

Dynamic Response of Forum Gdansk Structure due to Rail Traffic

Abstract This paper presents the study of the impact of vibration induced by the movement of the railway rolling stock on the Forum Gdańsk structure. This object is currently under construction and is located over the railway tracks in the vicinity of the Gdańsk Głowny and Gdańsk Środmieście railway stations. The analysis covers the influence of vibrations on the structure itself and on the people within. The in situ measurements on existing parts of the structure allow us to determine environmental excitations used for validation and verification of the derived FEM model. The numerical calculations made the estimates of the vibration amplitudes propagating throughout the whole structure possible.

Myocardial Infarction Risk Due to Aircraft, Road, and Rail Traffic Noise: Results of a Case–Control Study Based on Secondary Data

Traffic noise can induce stress reactions that have effects on the cardiovascular system. The exposure-risk relationship between aircraft, road, and rail traffic noise and myocardial infarction is currently unknown. 19 632 patients from the Rhine-Main region of Germany who were diagnosed with myocardial infarction in the years 2006-2010 were compared with 834 734 control subjects. The assignment of persons to groups was performed on the basis of billing and prescription data from three statutory health insurance carriers. The exposure of all insurees to aircraft, road, and rail traffic noise in 2005 was determined from their residence addresses. As estimators of risk, odds ratios (OR) were calculated by logistic regression analysis, with adjustment for age, sex, regional social status variables, and individual social status (if available). The evaluation was performed on the basis of the continuous 24-hour noise level and the categorized noise level (in 5 decibel classes). The linear model revealed a statistically significant risk increase due to road noise (2.8% per 10 dB rise, 95% confidence interval [1.2; 4.5]) and railroad noise (2.3% per 10 dB rise [0.5; 4.2]), but not airplane noise. Airplane noise levels of 60 dB and above were associated with a higher risk of myocardial infarction (OR 1.42 [0.62; 3.25]). This higher risk is statistically significant if the analysis is restricted to patients who had died of myocardial infarction by 2014/2015 (OR 2.70 [1.08; 6.74]. In this subgroup, the risk estimators for all three types of traffic noise were of comparable magnitude (3.2% to 3.9% per 10 dB rise in noise level). In this study, a substantial proportion of the population was exposed to traffic noise levels that were associated with an albeit small increase in the risk of myocardial infarction. These findings underscore the importance of effective traffic noise prevention.

An Improved Discrete-Time Model for Heterogeneous High-Speed Train Traffic Flow**Supported by the National Basic Research Program of China under Grant No. 2012CB725400, the National Natural Science Foundation of China under Grant No. 71222101, the Research Foundation of State Key Laboratory of Rail Traffic Control and Safety under Grant No. RCS2014ZT16, and the Fundamental Research Funds for the Central Universities No.

This paper aims to present a simulation model for heterogeneous high-speed train traffic flow based on an improved discrete-time model (IDTM). In the proposed simulation model, four train control strategies, including departing strategy, traveling strategy, braking strategy, overtaking strategy, are well defined to optimize train movements. Based on the proposed simulation model, some characteristics of train traffic flow are investigated. Numerical results indicate that the departure time intervals, the station dwell time, the section length, and the ratio of fast trains have different influence on traffic capacity and train average velocity. The results can provide some theoretical support for the strategy making of railway departments.

Capacity of Single-Track Railway Lines with Short Sidings to Support Operation of Long Freight Trains

Use of distributed-power locomotives in heavy-haul service has allowed for greater efficiencies through operation of longer freight trains. In North America, where the majority of main-line routes are single track, the potential economic and operational advantages offered by long trains are constrained by the inadequate length of many existing passing sidings. To implement longer trains, railroad operators may run long trains in a single direction or fleet trains or extend sidings enough to facilitate bidirectional operation of long trains. This research seeks to characterize the interaction between passing siding and train lengths and the subsequent effect on train delay. The operation of a single-track line is simulated under different combinations of freight throughput, percent of long sidings, percent of railcars in long trains, and directional distribution of long trains. The experiment design scenarios are simulated by using Rail Traffic Controller software. Results indicate that routes with roughly 50% of long sidings eliminate any delay-based consequences of running long trains on the route. Thus, to operate with a high percentage of long trains, only half of the sidings on a route need to be extended to maintain the baseline level of service. These results are expanded through discussion of their practical application in planning programs to either extend existing sidings or construct new longer-length sidings. The findings can streamline the decision-making process associated with capital expansion projects and further the understanding of relationships between siding and train lengths, thereby facilitating the sustainable expansion of existing rail corridors in anticipation of future demand.

Social Network Services for Rail Traffic Applications

With the rapid development of high-speed railway, subway, city railway, and intercity rail, how to ensure the reliability, safety, and comfort of such rail traffic transportation systems becomes the focus. Meanwhile, the social network service (SNS) is advancing so fast all over the world. How to combine the characteristics of rail traffic transportation systems with that of the social networks, which enable them to play an important role in the rail traffic operations, will become one of the core problems in the future development of intelligent rail traffic transportation systems. Based on the business requirements, the reliable transmission of information, and the characteristics of the rail traffic transportation systems, this article proposes a new concept of "dedicated social network" whose information are exchanged within the internal intranet. A novel social network architecture for rail traffic transportation system is proposed, including the SNS Management Center, a dedicated social network for internal information exchanges among the drivers, the dispatchers, and the train control center, the SNS for the information exchanges among the train marshals, crews, and passengers. The proposed framework attempts to exploit social networks in an active manner in the field of rail traffic transportation systems to make the system safer, more secure, reliable, comfortable, and humane.

Comparison of Capacity Expansion Strategies for Single-Track Railway Lines with Sparse Sidings

The North American railroad network is projected to experience increasingly constrained capacity. Growth in long-term demand for freight transportation combined with higher speeds and greater frequency of passenger trains operating on the same trackage will increase congestion at many locations. To accommodate this demand and maintain traffic fluidity, investment in projects to increase the capacity of many lines will be necessary. Recent changes in commodity flows, particularly related to rail transport of energy sources such as petroleum, alcohol, and coal, have led to growth on lines with historically lower traffic density and infrequent passing sidings that are too short for modern unit trains. This study aimed to find the most effective capacity expansion strategy for these single-track lines with sparse sidings. Rail Traffic Controller software was used to conduct experiments simulating traffic operation on such lines under several expansion alternatives, and the performance in terms of train delay and reliability was evaluated. The results suggest that for a single-track line with sparse sidings, the best strategy is first to construct new sidings between existing sidings in the middle of the corridor. Then these investments should be extended toward the two end terminals by constructing new sidings in successive gaps until the maximum number of sidings is reached. The results are also used to develop a relationship between the total length of the second main track and average freight train delay for use in planning capacity expansion on these lines.

Urban Rail Traffic Organization Scheduling Adjustment Method

This paper studies on urban rail traffic organization scheduling adjustment method. It describes different kinds of disturbance events that may occur in metro operation, and analyzes how various disturbance affect traffic order. It points out that the essence of disturbance is breaking the balance between transport capacity and demand, and the fundamental purpose of scheduling adjustment is to re-match capacity and demand. Its helpful to choose the most reasonable solution that making various disturbances effects on traffic. Available and matching scheduling adjustment methods for different disturbance scenarios are expounded in the paper.

Analysis of the Relationship between Land Use, Development, and Construction near a Rail Traffic Station and Passenger Flow Volume: The Case of Tianjin Metro Line 1

Tianjin Metro Line 1 opened to traffic in June 2006 and has now been in operation for seven years. During this time, Tianjin has grown and developed rapidly, and is facing land use, construction, and traffic challenges. This paper takes 20 stations along Tianjin Metro Line 1 as its research objects, and engages in field research and collection of essential materials and data to analyze the relationship between land use, development, and construction near the stations of Tianjin Metro Line 1 on the one hand and passenger flow volume on the other. On this basis, it offers suggestions for the further development of Tianjins rail network, including effective land utility mode and important facilities around the rail station that can increase passenger flow volume, improve land value and promote mutually benign development of both rail traffic and urban land.

Train Speed Control in Moving-Block Railway Systems: An Online Adaptive PD Controller Design

Since the overall capacity of railway lines are not used effectively in fixed-block railway systems, moving-block railway systems are introduced to increase the transport capacity and to reduce the headway times. CBTC (Communication Based Train Control) systems and ERTMS (European Rail Traffic Management System) application level 3 are regarded as examples of moving-block systems. In this study, the concept of moving-block system is explained and an adaptive PD control technique based on Online Least Square Support Vector Regression is used for train speed control.

An Explanation on Mechanism of Local Amplification in Attenuation of Ground Vibration from Rail Traffic in Urban Area

The mechanism of local amplifying on attenuation of ground vibration from urban rail traffic is deal with by Zheng et al (2011). The vertical vibrations on ground points of a model with single soil layer overlaid on elastic half-space is calculated with transfer matrix method in frequency domain. The results show that the amplification could be simulated well by the calculation, and the location and degree of the amplification are governed by the ratio between shear modulus of the the overburden layer and the half space , the thickness and damping ratio of soil layers. It is further pointed out in this paper that the most significant factor is the impedance ratio at the buried velocity interface. Then the mechanics is explained as the meeting of the directly arriving surface wave and the reflected and refracted waves from the interface.

Vibration Induced by Rail Traffic: Evaluation of Attenuation Properties in a Bituminous Sub-ballast Layer

The attenuation properties of a Hot-Mix Asphalt track bed containing crumb rubber (particle size 2-5mm) are evaluated. A large number of vibration measurements have been carried out in a test section of a railway interconnection (Turin-Milan HS Railway) where two solutions of 12cm of sub-ballast layer have been realized (with and without rubber). The vibrations were measured using a set of piezoelectric accelerometers positioned at various distances from the track to measure their generation and propagation. The results show that the new hot mix asphalt layer can influence the train vibration transmission.

Fatigue Assessment of Suspension Bridges Carrying Rail and Road Traffic Based on SHMS

Many long-span suspension bridges have been built around the world, and many of them carry both of rail and road traffic. Fatigue assessment shall be performed to ensure the safety and functionality of these bridges. This paper first briefly introduces the main procedure of fatigue assessment recommended by British Standard, and then it is applied to the Tsing Ma suspension bridge in Hong Kong. Vehicle spectrum of trains and road vehicles are investigated based on the measurement data of trains and road vehicles recorded by the Structural Health Monitoring System (SHMS) installed on the bridge so that fatigue damage assessment will be more realistic and accurate. Stress influence lines corresponding to railway tracks and highway lanes are established based on a complex finite element bridge model so that an accurate vehicle-induced stress response can be estimated based on them. The fatigue-critical locations for different type of bridge components are identified in terms of the maximum stress range due to a standard train running over the bridge. Finally, the fatigue life at the fatigue-critical locations due to both trains and road vehicles are estimated, and the result indicates the bridge is in very good condition.

Managing Rail Traffic on Commuter Lines Based on Dynamic Timetable Application

The increase of demand for transport service in rail commuter traffic stipulates higher ratio of consumed infrastructure capacity. In this method of traffic flow even minor deviations from the planned timetable can have negative influence on its stability, and this can result in major reduction of the quality of transport service. This research has defined the commuter rail traffic management system model with the application of real-time timetable rescheduling. It understands the application of the decision support system during the procedure of adjusting the timetable to the real condition in traffic in the form of genetic algorithm defined on the basis of the valid rules for the train and traffic control. Besides, this model in all the commuter trains understands the existence of the driver advisory system which is based on the algorithm for determination of the most favourable running regime with the aim of saving in energy consumption. The paper proves that by applying the proposed model the commuter rail traffic can be improved regarding the increase of the timetable stability and energy-efficient train operation. KEY WORDS: rail traffic management, genetic algorithm, energy efficient timetabling and train operation

Simulation-based evaluation of dependability and safety properties of satellite technologies for railway localization

Satellite-based localization technologies are strategic opportunities in railway applications because they offer new possibilities of service and have advantages that current technologies relying mainly on infrastructures deployed along tracks cannot equal. GNSSs (Global Navigation Satellite Systems) can, in particular, offer localization services in ERTMS (European Rail Traffic Management System), the system developed within the European railway community to harmonize, at European scale, railway signalling and control/command systems. However, using GNSS in such safety applications is slowed down when trying to comply with railway standards. Indeed, demonstrations of RAMS properties (Reliability, Availability, Maintainability, Safety) are required on new solutions embedded in trains. They aim at verifying if all dependability (RAM) and safety aspects are controlled over the lifecycle of the solutions before using them operationally. No RAMS evaluation technique exists for systems based on signal propagation and subject to failures provoked by environment effects. The major challenge is so to develop proof methods that will give means to fulfil the railway certification process. In this article, we propose a procedure to work in that direction after having presented the advantages, the possibilities and the challenges to use GNSS in rail transportation. The procedure is based on experiments for the evaluation of RAMS properties related to satellite-based localization units. We apply the method to different position measurements obtained in several typical railway environments. The obtained results are discussed according to the dependability and safety points of view.

Sound Radiation Characteristics of Wheels Used in Urban Rail Traffic

The wheel/rail noise is the main component of the urban rail traffic noise.And the sound radiation of the wheel is one of the most important sources of wheel/rail noise.The wheels used currently in urban rail traffic have varieties of types.The sound radiation of various types of the wheels is systematically compared in this paper,and the effect of different parameters on sound and vibration is analyzed.In the numerical simulation,also sound power levels of five types of the wheels are compared in detail.As the results,under the radial wheel/rail equivalent roughness excitation at the nominal contact position,increasing the thickness of web or decreasing the radius has a positive effect on reduction of acoustic radiation of wheel vibration.The levels of acoustic radiation and vibration of the wheels with curved web and doubled-S web are close.Compared to the wheels with the other two kinds of webs,the level of sound radiation and vibration of the wheel with straight web is the lowest,the sound power level of which is about 8dB smaller than that of the wheels with curved web and doubled-S web.The related calculation results will provide theoretical reference to the low noise design and the choice of the type of the wheel.

Interview

Professor Ai Bo from Beijing Jiaotong University in China is Vice Director of The State Key Laboratory of Rail Traffic Control and Safety. Here he talks about the research behind his group's Letter ‘Propagation measurements and analysis for high-speed railway cutting scenario' on page 1167.

Single and combined effects of air, road, and rail traffic noise on sleep and recuperation.

Traffic noise disturbs sleep and may impair recuperation. There is limited information on single and combined effects of air, road, and rail traffic noise on sleep and recuperation. Repeated measures. Polysomnographic laboratory study. 72 healthy subjects, mean ± standard deviation 40 ± 13 years, range 18-71 years, 32 male. Exposure to 40, 80, or 120 rail, road, and/or air traffic noise events. Subjects were investigated for 11 consecutive nights, which included 8 noise exposure nights and one noise-free control night. Noise effects on sleep structure and continuity were subtle, even in nights with combined exposure, most likely because of habituation and an increase in arousal thresholds both within and across nights. However, cardiac arousals did not habituate across nights. Noise exposure significantly affected subjective assessments of sleep quality and recuperation, whereas objective performance was unaffected, except for a small increase in mean PVT reaction time (+4 ms, adjusted P < 0.05). Road traffic noise led to the strongest changes in sleep structure and continuity, whereas subjective assessments of sleep were worse after nights with air and rail traffic noise exposure. In contrast to daytime annoyance, cortical arousal probabilities and cardiac responses were significantly lower for air than for road and rail traffic noise (all P < 0.0001). These differences were explained by sound pressure level rise time and high frequency (> 3 kHz) noise event components. Road, rail, and air traffic noise differentially affect objective and subjective assessments of sleep. Differences in the degree of noise-induced sleep fragmentation between traffic modes were explained by the specific spectral and temporal composition of noise events, indicating potential targets for active and passive noise control. Field studies are needed to validate our findings in a setting with higher ecologic validity.

MAS-Based Urban Rail Transport Ridership Forecast System and Traffic Generation Analysis

Ridership forecast of urban rail transport is one of the important bases for urban rail transport network planning, design, construction and operation. MAS-based ridership forecast system was designed and the architecture was proposed. The traffic generation forecast analysis was made from the three aspects of overall size forecast, resident population forecast and floating population forecast. The results showed that the system had the excellence of satisfying the randomness, non-linear and non-deterministic case for the strong adaptability, robustness and flexibility.

Commuter Rail Implementation Study for New Haven and Hartford, Connecticut, and Springfield, Massachusetts

Connecticut Department of Transportation, with the support of the Transportation Strategy Board, is preparing an environmental assessment for commuter rail service between New Haven and Hartford, Connecticut, and Springfield, Massachusetts. The study area corridor is 62 mi of existing rail line, which is owned and operated by Amtrak. This rail corridor line is commonly referred to as the Springfield Line. Besides a regional passenger service, four freight carriers use the line: Connecticut Southern, Pan Am Railways, CSX Corporation, and Providence and Worcester Railroad. A limited section of double track and long freight dwellings along the main line both demanded multiple alternatives to be analyzed according to capacity improvements and operational changes. Analysis was conducted by means of the Rail Traffic Controller software. The commuter plan was analyzed under two main scenarios: a start-up near-term service (Year 2015) and a future service (Year 2030). The outer year testing also included an iteration of improvements given implementation of high-speed rail on the line. The purpose of this discussion is to identify the track capacity and operational requirements for an efficient integration of freight, Amtrak, commuter, and high-speed rail service.