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Real-time train rescheduling for high-speed railway (HSR) is a pivotal technique in HSR transportation to efficiently recover train operation under disturbance scenarios. This paper aims to put forward an integrated resolving and rescheduling method considering network delay propagation. A tree-based conflict resolution mechanism is first established, with delicate considerations on the strategy's adaptability under different conflict scenarios. By inputting the scheduled arrival and departure time under different conflict resolution strategies, the timetable optimizing model aims to look for an optimal solution with minimal weighted train delay and average train adjustments under necessary technical and empirical constraints solved by a combined algorithm of Pareto optimality and Nash equilibrium, where the feasible solution space is narrowed in advance by a depth-first pruning algorithm. The performance of this coordinated train rescheduling approach is validated by a typical section disturbance in a regional HSR network administrated by the Shanghai Bureau. The results show that the proposed method can well utilizes timetable buffers and organizes train avoidance. The delay propagation characteristics are also simultaneously estimated based on the indicators of cumulative delay and instantaneous delay, which are established considering the spatio-temporal difference between the scheduled and planned timetables, in order to verify the coordination between resolution strategies and train running delays., Author(s): Jun Zhang (corresponding author) [1]; Shuyao Wu [1]; Shejun Deng [1]; Yuling Ye [2] 1. Introduction Under the network transportation of high-speed railway (HSR), disturbances of abnormal events are [...]

Since unexpected event occurrences are inevitable, an efficient and effective rescheduling approach is critical in freight railway day-to-day operations. Represented by the minimal-delay objectives, the most commonly used efficiency-oriented approach ignores the role of train priority and poses equity problems in rescheduling. For equity, different train priority also reflects the preference in deciding train orders; i.e., the high-priority train is likely to be favorable. However, a conflict may be laid between reducing delays and emphasizing train priority. Hence, it is critical to decide the criteria in train order for freight railway, especially with heterogeneous priority in a competitive resource. To make a tradeoff between equity and efficiency, this paper makes train priority evolutionary and proposed the dynamic train priority considering delay time and static priority. We formulate an optimization model based on the rescheduling strategies such as retime, reorder, and retrack in a complex railway network containing single-track, double-track, and quadruple-track sections. An integrated two-dimension genetic algorithm (ITGA) approach is developed to reobtain an optimized timetable of sufficient quality while meeting the time requirements for real-time rescheduling. In the experiment, the effectiveness of the ITGA approach was employed in a simple case and a real-world case in the Netherlands freight railway. The result shows that there is a synergy between delay time and train priority, where the threshold to upgrade the evolutionary train priority plays an important role. The proposed approach is compared with the benchmark solution first-in-first-out (FIFO) approach in a real-world case to verify the performance and efficiency. Our work extends the rescheduling approach considering both equity and efficiency and provides auxiliary operation support for the dispatcher's operation rescheduling., Author(s): Zhuotong Bai [1]; Hui Wang [2]; Lin Yang [3]; Jiajie Li [4]; Huapu Lu (corresponding author) [1] 1. Introduction Freight railway holds an increasing market share in transportation systems [...]

Railway freight rates are seen as a key driving factor of global trade activities, influenced by numerous factors. Given the limitations of fuzziness and randomness of variable quantification in the previous studies, this paper proposes a cognitive cloud model of factors influencing railway bulk goods freight rates. In the cognitive cloud model, randomness and fuzziness are described by three parameters. Furthermore, a cloud generator including forwarding and backward cloud generators is designed to solve the bidirectional conversion between qualitative indicators and quantitative values. In addition, we propose a floating cloud gathering algorithm to determine the weight of the index system to solve the uncertainty problem in the transformation process of qualitative indicators. Finally, the cognitive cloud model and the adapted algorithm are used to perform an in-depth analysis of the affecting factors of Z Railway Bureau freight transport pricing., Author(s): Jingwei Guo [1,2,3]; Yimin Wang (corresponding author) [2]; Yang Qin [4]; Qinglin Li [1]; Zhongqi Xie [2]; Xin Qin [2] 1. Introduction To engender effective influencing factors evaluation, various [...]

Railway systems should be resilient to play a key role in creating sustainable development. Single-track railway lines are seen as potential bottlenecks due to limited capacity. More advanced railway interlocking systems (such as ETCS or satellite-based control systems) are being developed. On the other hand, the installation of these interlocking systems is a complex and time-consuming and costly task. For this reason, it is necessary to recognize the impact of potentially installed system with capacity, stability of timetable, quality, and other associated effects. The assessment is based on a set of simulation experiments using stochastic microscopic simulation model in the OpenTrack software tool. The focus is on railway operation with automatic block and automatic line blocking systems. If these two systems will have positive capacity effects, it is a basic presumption also for systems such as moving block (e.g., ETCS L3) to be effective. Research has shown that the significance of such measures can be best supported by linking to a matching timetable concept that will make full use of the benefits offered by these interlocking systems. The results reached in this research should be potentially applied, for example, by prioritizing of single-track railway lines for possible installation of such interlocking system. It can be achieved based on the capacity and operational effects examined., Author(s): Michael Bažant (corresponding author) [1]; Josef Bulíček [2] 1. Introduction Railway industry plays a key role within an effort to create a sustainable environment. The issue is that there [...]

The hierarchical connection of Rail Traffic Management System (TMS) and Automatic Train Operation (ATO) for mainline railways has been proposed for a while; however, few have investigated this hierarchical connection with the real field. This paper studies in detail the benefits and limitations of an integrated framework of TMS and ATO in stochastic and dynamic conditions in terms of punctuality, energy efficiency, and conflict-resolving. A simulation is built by interfacing a rescheduling tool and a stand-alone ATO tool with the realistic traffic simulation environment OpenTrack. The investigation refers to different disturbed traffic scenarios obtained by sampling train entrance delays and dwell times within a typical Monte Carlo scheme. Results obtained for the Dutch railway corridor Utrecht-Den Bosch prove the value of the approach. In case of no disruptions, the implementation of ATO systems is beneficial for maintaining timetables and saving energy costs. In case of delay disruptions, the TMS rescheduling has its full effect only if trains are able to follow TMS rescheduled timetables, while the energy-saving by using ATO can only be achieved with conflict-free schedules. A bidirectional communication between ATO and TMS is therefore beneficial for conflict-resolving and energy-saving., Author(s): Pengling Wang (corresponding author) [1,2,3,4]; Annik Jeiziner [5]; Xiaojie Luan [4]; Valerio De Martinis [4,6]; Francesco Corman [4] 1. Introduction In railway systems, intelligent rescheduling (Traffic Management System, TMS) [...]

This article analyses a selection of South African English and Afrikaans humorous and satirical poems and songs about the railways. They include a folksong, 'The Kimberley Train', which dates back to the earliest expansion of the railways to the interior, and poems and songs from the 1960s to the early 90s. While Hugh Masekela raged at the condition of migrant miners, the target of the satire by English- and Afrikaans-speaking writers was the Afrikaner nation, its culture and history. Four of the poems are ballads in the heroic tradition. The characters featured are working-class Afrikaners, and the diction employed is a colloquial South African dialect consisting of modern slang, mixed English and Afrikaans, and Fanakalo. A common method of the humour and satire exploits the connotations of personal and place names. KEY WORDS Railway poems, railway songs, South African satire, South African poetry, South African folksongs, South African English dialect, People of different cultures have celebrated the railways--the trains, those who work on them and those who travel in them--in poetry and song. The French cherish lapoesie ferroviaire, and even [...]

The current preemption method for traffic signals at intersections located near highway-rail grade crossings (IHRGC) is known as the standard preemption (SP). The SP strategy is designed to give priority to the phases which clear vehicles off the railroad tracks as quickly as possible before a train arrives at HRGCs and provides the drivers and pedestrians with a minimum warning time (MWT). However, the SP considers neither pedestrian safety nor system efficiency at IHRGCs. As a result, this may lead to safety and delay problems at IHRGCs. To solve the problems, a state-of-the-art transition preemption strategy (TPS) algorithm, named TPS_DT, is developed in this paper. The new TPS algorithm is designed for corridors with multiple HGRCs that have dual tracks. An urban highway corridor with multiple HRGCs in Lincoln, NE, was selected as the study corridor. A calibrated VISSIM model of the study corridor was used to test the safety and efficiency of the proposed algorithm. The algorithm was coded in VAP, which is an add-on module of VISSIM. A roadway-railway corridor with multiple IHRGC and dual rail tracks in Lincoln, NE, was used as the testbed. The Measurements of Effectiveness (MOEs) used for evaluation include the rate of pedestrian phase cutoffs, intersection vehicle delay, and corridor vehicle delay. It was found that TPS_DT can significantly improve pedestrian safety and reduce vehicle delay at IHRGCs. Furthermore, the effects of train arrival prediction errors on safety and efficiency of the IHRGCs are also analyzed in the paper., Author(s): Yifeng Chen (corresponding author) [1]; Laurence R. Rilett [2]; Zifeng Wu [3] 1. Introduction Highway-rail grade crossings are locations where a highway and railway intersect at the same level [...]

Chinese high-speed railway has implemented large-scale network operation with an urgent need for capacity improvement. The concept of virtual coupling seems to be a promising solution that provides a new operational scenario for high-speed railway, where trains are formed into a cooperative convoy and run synchronously with small train headways. The train-following principles under the virtual coupling signalling are quite different from those under conventional train control systems. Therefore, train headway analysis for different operational scenarios should be carried out to ensure railway safety and evaluate capacity benefits brought by virtual coupling. This paper proposes a potential virtual coupling architecture with reference to ETCS/ERTMS specifications. We compare blocking time models under different train control systems, and eight typical train-following scenarios are investigated for virtual coupling, including train arrival and departure cases. A detailed multiscenario-based train headway analysis is provided based on the microscopic infrastructure of the station and technological characteristics of virtual coupling. All computational outcomes are based on the train dynamic motion model. A comparative analysis of train headways under virtual coupling and CTCS-3 is provided in the case study. Results show that train headways can be substantially reduced under virtual coupling and are related to the station infrastructure layout., Author(s): Jinyi Pan [1]; Qiyuan Peng [1,2,3]; Shuguang Zhan (corresponding author) [1,2,3]; Jiaqi Bai [4] 1. Introduction In China's high-speed railways, oversaturated utilization of capacity has become prominent with the [...]

The advantage of multimodal transport is that it can deliver the goods to their destination in a reasonable combination of transport modes while ensuring security and punctuality. Multimodal transportation can effectively reduce logistics costs, improve logistics efficiency, and reduce environmental pollution. In the process of multimodal transportation, due to the interference of natural factors (weather, terrain, etc.) and some special human factors, it may have different degrees of impact on the transportation time and transportation safety of different transportation modes. Therefore, when choosing a transportation method, it is necessary to consider the transportation time and transportation safety under the interference. However, the current research on multimodal transport has not considered the impact of external interference on transportation time and transportation safety. Compared with other modes of transportation, external interference has a relatively small impact on railway transportation. Railways can safely deliver goods to their destinations on time. Under the background of China's huge railway network and advanced heavy-duty technology, this paper establishes a multimodal transport route selection model for considering railway as the core, introduces time penalty cost and damage compensation cost, and takes the lowest comprehensive transportation cost as the model objective under the premise of considering transportation reliability and transportation safety. Finally, taking a multimodal transport network in China as an example, an improved ant colony algorithm is used to solve the model and the results verify the rationality of the model., Author(s): Hui Zhang [1,2,3,4]; Yao Li [1]; Qingpeng Zhang [5]; Dingjun Chen (corresponding author) [1,2,3] 1. Introduction Multimodal transport [1] is a mode of cargo transportation through the connection and [...]

It is known that it is critical for train rescheduling problem to address some uncertain disturbances to keep the normal condition of railway traffic. This paper is keen on a mathematical model to reschedule high-speed trains controlled by the quasi-moving blocking signalling system impacted by multidisturbances (i.e., primary delay, speed limitation, and siding line blockage). To be specific, a mixed-integer linear programming is formulated based on an improved alternative graph theory, by the means of rerouting, reordering, retiming, and train control. In order to adjust the train speed and find the best routes for trains, the set of alternative arcs and alternative arrival/departure paths are considered in the constraints, respectively. Due to this complex NP-hard problem, a two-step algorithm with three scheduling rules based on a commercial optimizer is applied to solve the problem efficiently in a real-word case, and the efficiency, validity, and feasibility of this method are demonstrated by a series of experimental tests. Finally, the graphical timetables rescheduled are analysed in terms of free conflicts of the solution. Consequently, the proposed mathematical model enriches the existing theory about train rescheduling, and it can also assist train dispatchers to figure out disturbances efficiently., Author(s): Peijuan Xu [1]; Dawei Zhang (corresponding author) [2,3]; Jingwei Guo [4]; Dan Liu [1]; Hui Peng [1] 1. Introduction High-speed railway faced a rapid development in the world and [...]

Abstract. This paper evaluates the robustness of a railway network with respect to operational delays. It assumes that trains in the network operate on fixed routes and with reference to [...]

High-speed railway (HSR) transportation poses a serious challenge to dispatchers, whose job performance plays a critical role for the safety and efficiency of the transportation system. This study examined the relationship between cognitive and mental factors and job performance among Chinese high-speed railway dispatchers and established a predictive model for the job performance of dispatchers. Cognitive abilities involved in train dispatching including working memory and multiobject tracking and potential related mental factors including depression, anxiety, perceived stress, and social support were examined. Job performances were measured by both subjective and objective indicators, i.e., the overall evaluation by supervisors and the delay time by dispatching simulator. Stepwise regression results showed that both cognitive abilities and 2 mental factors (depression and perceived stress) have strong relations with job performance, and tremendous distinction between groups of good and poor performance of HSR dispatchers is revealed. The predictive model accounted for 91% of the overall variance in objective performance indicator and has 96% distinguished accuracy of good and poor groups. These findings imply that cognitive and mental factors should be of great concern to the current practice of Chinese HSR dispatcher selection and management., 1. Introduction With the share of China accounting for about 2/3 of the world high-speed railway (HSR) mileage [1], the daily transportation of China's high-speed trains is about 1.33 million, [...]

Crew costs are a significant portion of rail operating expenses, and so effective deployment of train crews is an important priority for freight railroads. This paper proposes an optimization model [...]

In this paper, the statistical distribution of railway track geometry data is investigated using a significant volume of field data. Analyzing the results yields a general pattern for the statistical distribution of the track geometry data. This is used to develop new indexes for track geometry parameters including gauge, profile, alignment, and twist. An overall track geometry index is established by combining the new parameter's indexes. This combination is made by assigning a coefficient to each geometry parameter based on its role in the overall quality condition of the track. In comparison with the approaches previously used for the development of the track geometry indexes, this method has three distinguishing features. First, the mean values along with the SD of data are incorporated into the calculation of the new indexes. Second, the new indexes indicate not only the condition of the individual parameters but also the overall track geometry condition. Third, the track classification is considered, and an index is developed for each class of the tracks. A practical use of the new indexes is presented and discussed in the paper. DOI: 10.1061/(ASCE)0733-947X(2010)136:8(693) CE Database subject headings: Geometry; Alignment; Railroad tracks; Statistics. Author keywords: Geometry index; Twist; Profile; Alignment; Gauge; Standard deviation; Mean.

To authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1468-0335.2008.00739.x Byline: GUIDO FRIEBEL ([dagger],[double dagger],s.), MARC IVALDI ([dagger],s.), CATHERINE VIBES ([dagger]) Abstract: We estimate the effects of reforms on railroad efficiency in Europe by using a new panel data set that covers most EU countries over a period of more than 20 years. A production frontier model finds that efficiency increases when reforms such as third-party network access, introduction of an independent regulator, and vertical separation are implemented. However, the reform effects depend on sequencing: introduction of multiple reforms in a package has negative effects, while sequential reforms improve efficiency. We also show that our results are robust against potential problems of endogeneity. Author Affiliation: ([dagger])Toulouse School of Economics ([double dagger])Goethe University Frankfurt (s.)CEPR Article History: Final version received 29 March 2008.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ejor.2007.06.062 Byline: Xavier Delorme (a), Xavier Gandibleux (b), Joaquin Rodriguez (c) Keywords: Transportation; Multiple objective programming; Railway infrastructure capacity; Timetable stability; Shortest path Abstract: This research deals with a real-world planning problem in railway infrastructure operations. It is part of the RECIFE project, which seeks to develop a decision support software to help evaluate the capacity of a rail junction or station. To this end, the project is working on a timetable optimization model, as well as timetable evaluation modules. This paper presents a module for evaluating timetable stability, which uses an original method based on delay propagation and using shortest path problem resolution. A didactic example and a complete case study applying this method to the Pierrefitte-Gonesse junction are also presented. Author Affiliation: (a) Centre Genie Industriel et Informatique, Ecole Nationale Superieure des Mines de Saint-Etienne, 158 cours Fauriel, F42023 Saint-Etienne Cedex 2, France (b) LINA, Universite de Nantes, 2 rue de la Houssiniere BP 92208, F44322 Nantes Cedex 03, France (c) INRETS-ESTAS, 20 rue Elisee Reclus, F59650 Villeneuve d'Ascq, France Article History: Received 15 January 2007; Accepted 18 June 2007

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.apergo.2008.04.010 Byline: Brendan Ryan (a), John R. Wilson (a)(b), Sarah Sharples (a), Theresa Clarke (c) Keywords: Rail human factors; Survey administration and analysis; Comparisons of roles Abstract: REQUEST, the Rail Ergonomics Questionnaire, has been designed to survey attitudes and opinions of railway signallers and those in associated roles on a range of human factors such as job satisfaction, the workplace, culture or stress. The development of the survey instrument has been described in Ryan et al. [2008. Developing a rail ergonomics questionnaire (REQUEST). Appl. Ergon., doi:10.1016/j.apergo.2008.04.006.]. The present paper presents an overview of findings from this national survey which achieved a sample size of 3889 and a response rate of 83%. Findings are compared by different roles (e.g. signaller, controller) on a range of main scales and responses to additional questions in the survey. Ratings from the largest of the occupational groups, the signaller at 83.1% of the overall population, have been compared according to different types of signalling system used, identifying different characteristics in the use of lever, panel and VDU signalling systems. Comparisons of signallers' ratings by geographical location have produced findings of interest at different layers of management of the organisation, identifying locations with high or low ratings on a range of scales. The findings provide valuable information for the client organisation, using direct input from frontline staff on a range of human factors issues. This was a large survey, one of the largest ever civilian human factors surveys, involving lengthy, often repetitive and frequently complex analyses. Lessons learned within the administration of the survey, the analysis of the data and dissemination of the findings will be of interest to researchers. An overview of the scope of analyses of the database is introduced, in addition to proposals for further development of the survey instrument. Author Affiliation: (a) Institute for Occupational Ergonomics, University of Nottingham, University Park, Nottingham NG7 2RD, UK (b) School of Risk and Safety Science, University of New South Wales, Australia (c) Ergonomics National Specialist Team, Network Rail, Melton Street, London, UK Article History: Received 9 July 2007; Accepted 3 April 2008

This article examines the reciprocal relationships between work variables and health outcomes and if these relationships differ by social class (measured by occupational grouping). We used longitudinal data from the 1994/95-2002/03 Canadian National Population Health Survey (NPHS). Karasek's work stress variables were measured in the 1994/95 (cycle 1, time 1), 2000/01 (cycle 4, time 2) and 2002/03 (cycle 5, time 3) surveys. Analyses were limited to 2556 respondents aged 18-56 at time 1 and who remained in the same social class (as defined by occupational position) for all the three time points. Work variables used were job strain ratio, work social support and job insecurity. Health outcomes used were distress, depression and self-rated health. Multi-group path analyses were used to investigate the reciprocal relationships between work and health variables and if these relationships differed by social class. Analyses controlled for age, gender, marital status and work status. We find there is a differential burden of work psychosocial factors and health outcomes by social class. The cross-lagged relationships between work and health depended on the outcome, social class and time lag. More significant paths from work to health were observed than reverse paths from health to work. More significant relationships between work and health were observed for the shorter time lag (2 years) compared to longer time lags (6 years). Low work social support and job insecurity were more detrimental to health for respondents in lower social class positions. Findings from this study highlight the importance of time lag, and to some extent social class, in the reciprocal relationships between work and health. Keywords: National Population Health Survey Path analysis Cross-lagged Reciprocal Time lag Moderation Work stress Canada

Objects intruding high-speed railway clearance do great threat to running trains. In order to improve accuracy of railway intrusion detection, an automatic multimodal registration and fusion algorithm for infrared and visible images with different field of views is presented. The ratio of the nearest to next nearest distance, geometric, similar triangle, and RANSAC constraints are used to refine the matching SURF feature points successively. Correct matching points are accumulated with multiframe to overcome the insufficient matching points in single image pair. After being registered, an improved Contourlet transform fusion algorithm combined with total variation and local region energy is proposed. Inverse Contourlet transform to low frequency subband coefficient fused with total variation model and high frequency subband coefficients fused with local region energy is used to reconstruct the fused image. The comparison to other 4 popular fusion methods shows that our algorithm has the best comprehensive performance for multimodal railway image fusion., 1. Introduction High-speed railway is a competitive transportation all over the world. As of 2017, the length of commercial high-speed railway lines in China had exceeded 25,000 km. With the [...]

Simultaneously considering train scheduling problem and maintenance planning problem with uncertain travel time, we propose a two-stage integrated optimization model for the sunset-departure and sunrise-arrival trains (SDSA-trains). Specifically, in the first stage, we obtain an optimal solution of the SDSA-trains under each scenario, which leads to the minimum total travel time. In the second stage, a robust SDSA-train schedule is generated based on the optimal solutions of the first stage. The key is that we consider two operation modes to solve the conflict between the SDSA-trains and the maintenances. Some state variables are used to deal with train operation mode selection. Furthermore, some linearization techniques are used to formulate a mixed-integer linear programming (MILP) model. Finally, numerical experiments are implemented to prove the effectiveness of the proposed model and optimization method., 1. Introduction Desirable train schedules are important to ensure the efficient operation of the high-speed railway system, but some uncertain events (e.g., bad weather conditions, equipment failure) often occur due [...]

In the forthcoming decades, railway transport is expected to face a significant growth of traffic flows which will mostly have to be accommodated over the existing infrastructures. An increase of [...]

Railroads ship individual cars according to blocking plans that route the cars in groups (blocks) that share common intermediate stops. An individual shipment is regrouped (reclassified) two to three times along the way from its origin to destination. Yards are crucial facilities of the rail network where cars are reclassified according to such blocking plans. Therefore, yard locations and the blocking plan impose the detour and classification of cars over the physical network. Yards are capacitated with respect to number of blocks made and number of cars classified; rail lines between major stations are capacitated with respect to number of cars that pass through. These restrictions are accounted for in designing the blocking plans. Changing the yard locations and expanding associated capacities may result in dramatic changes in blocking plans saving tens of millions of dollars in railroad transportation costs. We develop a mathematical programming formulation and propose solution methods for the yard location problem and the capacity expansion problems. We demonstrate that the railroads can save significantly by reconfiguring their networks. Journal of the Operational Research Society (2008) 59, 911-920. doi: 10.1057/palgrave.jors.2602403 Keywords: rail transport; strategic planning; location; heuristics

To purchase or authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1475-4932.2008.00449.x Byline: NICK WILLS-JOHNSON (1) Keywords: L11; L52; L92 Abstract: Economic reform in the mid-1990s saw the application of third-party access to railway infrastructure and, in some cases, the separation of above-rail and below-rail services into separate businesses. Reform was based on the notion that the rail track was a natural monopoly, while the above-rail sector could potentially support competition. This paper examines the likelihood of such competition through an analysis of subadditivity, and also the consequences of vertical separation for rail efficiency. It finds limited evidence for sustainable above-rail competition, but also limited evidence that vertical separation should have caused efficiency losses. Author Affiliation: (1)Planning and Transport Research Centre, Curtin University of Technology, Perth, Western Australia, Australia Article note: Correspondence: Nick Wills-Johnson, Curtin University of Technology, GPO Box U1987, Perth, WA 6845, Australia. Email: n.wills-johnson@curtin.edu.au

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ejor.2006.10.034 Byline: Andrea D'Ariano (a), Dario Pacciarelli (b), Marco Pranzo (c) Keywords: Train scheduling; Real-time conflict resolution; Alternative graph; Branch and bound algorithm Abstract: The paper studies a train scheduling problem faced by railway infrastructure managers during real-time traffic control. When train operations are perturbed, a new conflict-free timetable of feasible arrival and departure times needs to be re-computed, such that the deviation from the original one is minimized. The problem can be viewed as a huge job shop scheduling problem with no-store constraints. We make use of a careful estimation of time separation among trains, and model the scheduling problem with an alternative graph formulation. We develop a branch and bound algorithm which includes implication rules enabling to speed up the computation. An experimental study, based on a bottleneck area of the Dutch rail network, shows that a truncated version of the algorithm provides proven optimal or near optimal solutions within short time limits. Author Affiliation: (a) Department of Transport and Planning, Delft University of Technology, P.O. Box 5048, 2600 GA Delft, The Netherlands (b) Dipartimento di Informatica e Automazione, Universita degli Studi Roma Tre, via della vasca navale, 79 - 00146 Roma, Italy (c) Dipartimento di Ingegneria dell'Informazione, Universita di Siena, via Roma, 56 - 53100 Siena, Italy Article History: Received 27 October 2005; Accepted 5 October 2006

This paper describes the development of a model which can be used to evaluate the reliability of a sleeper system when the sleeper condition is known. Two cases that are of particular interest to the railway industry are investigated. These are the failure of a sleeper system caused by at least two consecutive failed sleepers and by at least three consecutive failed ones, respectively. A model to optimize sleeper maintenance is proposed, which minimizes the number of sleepers restored during immediate maintenance subject to meeting the requirements of reliable and safe sleeper operation. Finally, an example is given to illustrate the model. Keywords: reliability; maintenance; railway sleeper; decision-making

The effect of disabled fastening systems and ballast on railway vehicle derailment is investigated by developing a nonsymmetrical coupled vehicle/track model. In the model a half passenger car is considered, and modeled with a multi-body system with 18 degrees of freedom, which runs on a tangent track at a constant speed. The tangent track is modeled as two elastic beams by discrete nonsymmetrical supporters modeling fastening systems, sleepers, and ballasts. The normal contact forces between wheels and rails are described by Hertzian elastic contact theory, and the tangential forces by the nonlinear creep theory of Shen et al. (Proceedings of the 8th IAVSD Symposium, Cambridge, MA, pp. 591-605). In the numerical analysis, the disabled rail fastening, rail pad, and ballast, on one and two sides of the track are, respectively, considered. Through a detailed analysis, derailment coefficients and the track state variations are obtained. The derailment coefficients are defined as the ratio of the lateral force to the vertical force of the wheel and rail (indicated by L/V), duration of L/V, and rate of the wheel load reduction (indicated by [DELTA]V/V), respectively. The variations of the contact points on the wheel treads, the track gauge, the track cross-level, and rail turnover angle are present in the paper The numerical results obtained indicate that the failure of rail supports has a great influence on the vehicle running safety. [DOI: 10.1115/1.2424978] Keywords: railway vehicle, track, derailment, coupling dynamic, wheel/rail interaction, creep force

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ejor.2005.10.037 Byline: Fausto Pedro Garcia Marquez (a), Diego Jose Pedregal Tercero (a), Felix Schmid (b) Keywords: Maintenance; Reliability; Unobserved Components models; Condition monitoring; Points mechanisms Abstract: Railways are experiencing a fundamental transformation. The introduction of high speed networks and the increased traffic levels on suburban routes and freight lines require new technologies for both railway infrastructure and trains, all of which must be subjected to rigorous quality control before and during operation and must be supported with effective maintenance processes during their operating lives. Safety in railway infrastructure provision must be ensured by all the main components operating reliably all the time. From an economic, quality and safety point of view, points are probably one of the most critical infrastructure elements in railway transportation. Most problems with points mechanisms are associated with either wear of components or movements of the sleepers and rails resulting from the normal behaviour of ballasted track. Therefore, railway points require regular adjustment to compensate for wear in switch rails, cams, hinges of linkages and detection switches. Consequently, a dependable method of wear control is required. Ideally, this should involve only minimal human intervention, particularly with regard to wear of the tracks. The method for assessing wear proposed in this paper is based on a robust remote monitoring system. It involves the collection and transmission of time varying data and the analysis of the signals. The authors put forward models to monitor wear based on the signal analysed for detecting the state of points mechanisms. The models explored in this paper in real time belong to the so called Unobserved Components class of models, set up in a State Space framework. The unknown elements in the system matrices are estimated by a maximum likelihood algorithm, and they are generally updated each time new data becomes available. The system developed has been tested in numerous experiments to demonstrate its efficiency and it is able to find potential hazards. Typical wear-inducing faults were introduced intentionally during the experiments on which the present paper is based. Author Affiliation: (a) ETSII de Ciudad Real, Universidad de Castilla-La Mancha, C/Erillas 42, 45516 La Puebla de Montalban (Toledo), Spain (b) Mechanical Engineering Department, Sheffield University, England, United Kingdom Article History: Received 5 March 2005; Accepted 27 October 2005

Treatment selection bias leads to an inaccurate estimation of treatment effects as applied to specific sites or problem locations. Treatment selection bias is a major source of inconsistency in the results obtained from conventional before and after and cross-sectional models. One of the major expressions of treatment selection bias concerns the use of collision occurrence data in justifying intervention. For example, in highway safety field, a treatment is often introduced at a given site based on its high collision experience. Under normal conditions we would expect these collision numbers to return to a lower long term expected value, regardless of intervention. For treated sites, conventional observational models ascribe this reduction in collisions to the given treatment. This results in an overestimation of treatment effect. In this paper, a propensity score model is introduced that deals explicitly with treatment selection bias. The model is applied to Canadian highway--railway grade crossings data to estimate reductions in collision subject to upgrades in warning devices. The results of the propensity score model are compared for similar types of treatments to a number of before and after and cross-sectional models for both U.S. and Canadian data. The propensity score method is shown to reduce treatment selection bias and has probable merit that need to be further examined. DOI: 10.1061/(ASCE)0733-947X(2007)133:2(112) CE Database subject headings: Safety; Railroad grade crossings; Evaluation; Statistics.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ejor.2004.12.013 Byline: P. Vansteenwegen, D. Van Oudheusden Keywords: Robustness; Linear programming; Timetabling; Railway connections; Buffer times Abstract: In order to improve passenger service, a waiting cost function, weighting different types of waiting times and late arrivals, is designed and minimised. The approach is applied to a small part of the Belgian railway network. In the first phase of the approach, ideal buffer times are calculated to safeguard connections when the arriving train is late. These buffer times are based on the delay distributions of the arriving trains and on the weighting of different types of waiting times. In a second phase, standard linear programming is used to construct an improved timetable with well-scheduled connections and, whenever possible, with ideal buffer times. Simulation compares different timetables and optimises the LP timetable. For the case of the Belgian railway network, the final result is a timetable with well-scheduled connections and a waiting cost that is 40% lower than the current timetable. Since only LP modelling is applied, the proposed technique is very promising for developing better timetables -- even for very extensive railway networks. Author Affiliation: Centrum voor Industrieel Beleid, Katholieke Universiteit Leuven, Celestijnenlaan 300A, 3001 Leuven, Belgium Article History: Received 21 November 2003; Accepted 9 December 2004

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ejor.2004.10.010 Byline: Michiel J.C.M. Vromans (a), Rommert Dekker (b), Leo G. Kroon (c)(d) Keywords: Railways; Transportation; Reliability; Heterogeneity; Simulation Abstract: Reliability is one of the key factors in transportation, both for passengers and for cargo. This paper examines reliability in public railway systems. Reliability of railway services is a complex matter, since there are many causes for disruptions and at least as many causes for delays to spread around in space and time. One way to increase the reliability is to reduce the propagation of delays due to the interdependencies between trains. In this paper we attempt to decrease these interdependencies by reducing the running time differences per track section and by thus creating more homogeneous timetables. We also introduce two heuristic measures, that can be used to evaluate the homogeneity of a timetable. Because of the complexity of railway systems, we use network wide simulation for the analysis of the alternative timetables. We report on both theoretical and practical cases. Besides a comparison of different timetables, also general timetabling principles are deduced. Author Affiliation: (a) ProRail, Infrastructure Planning Department, Utrecht, The Netherlands (b) Department of Econometrics and Operations Research, School of Economics, Erasmus University Rotterdam, The Netherlands (c) Department of Decision and Information Management, School of Management, Erasmus University Rotterdam, The Netherlands (d) Logistics Department, Netherlands Railways, Utrecht, The Netherlands Article History: Received 5 January 2004; Accepted 22 October 2004

Two methods are illustrated to effectively calculate the ground motion induced by constant speed moving loads. On the one hand, the dynamic Betti--Rayleigh reciprocity theorem allows one to take full advantage of the availability of Green's functions for a homogeneous or a horizontally layered half-space. On the other hand, the spectral element method allows one to deal with complicated configurations, including dynamic soil-structure interaction, with an accuracy that is significantly higher than classical finite element or finite difference methods. Both the Betti--Rayleigh and spectral element methods are considered in three dimensions. After validating both methods, the decay of peak ground motion with distance is analyzed as a function of load speed and frequency. For speeds lower than the Rayleigh wave velocity in the soil, the decay turns out to be much faster than for a stationary point load. This effect is studied in detail by an analytical approach and interpreted in terms of destructive interference. Finally, the previous analytical and numerical results are checked against the records obtained at Ath, Belgium, during a field experiment to study ground motion induced by high-speed trains in soft soil conditions. DOI: 10.1061/(ASCE)0733-9399(2006)132:2(201) CE Database subject headings: Railroad tracks; Railroad trains; Vibration; Ground motion; Numerical analysis.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ejor.2004.04.036 Byline: Jan-Willem Goossens (a), Stan van Hoesel (a), Leo Kroon (b) Keywords: Integer programming; Combinatorial optimisation; Railway transportation Abstract: An important strategic element in the planning process of a railway operator is the development of a line plan, i.e., a set of routes (paths) on the network of tracks, operated at a given hourly frequency. The models described in the literature have thus far considered only lines that halt at all stations along their route. In this paper we introduce several models for solving line planning problems in which lines can have different halting patterns. Correctness and equivalence proofs for these models are given, as well as an evaluation using several real-life instances. Author Affiliation: (a) Department of Quantitative Economics, University of Maastricht, P.O. Box 616, 6200 MD Maastricht, The Netherlands (b) Rotterdam School of Management, Erasmus University Rotterdam, P.O. Box 1738, 3000 DR Rotterdam, The Netherlands Article History: Received 14 May 2003; Accepted 19 April 2004

Taipei Metro adopted the diode-grounded scheme for stray current collection in construction of its cross rail network. During operation of the network, a high rail-to-earth potential ([V.sub.rali]) has been observed at the east end of the Blue Line (i.e., stations BL13-BL16). To find effective countermeasures, a series of field tests in a step-by-step development nature was conducted from 1999-2000, which led to the decision of disconnecting the impedance bond at G11 of the tie line so that the negative return current of the Blue Line cannot flow to the rails of the Red-Green Line, and vice versa (detailed in Sections III-A and V-C). This decision was implemented through contract-out work in 2003. Since then, the Frail has been lowered by almost half before disconnection. To gain the insight characteristic before the contract-out, numerical simulations were also conducted by simulating the multi-train and multisection features of the cross transportation network. The simulation results (for [V.sub.rail] and stray current, or [I.sub.stray]) were consistent with the field-test results. This paper presents the design of these field tests and their test results in comparison with the simulation results, based on which the countermeasures for reducing [V.sub.rail] and the present status after Frail reduction at Taipei Metro are presented. Index Terms--DC transit railway, diode-grounded, field tests, multi-train simulation, rail-to-earth potential, stray current.

In the locomotive-scheduling problem (or the locomotive-assignment problem), we must assign a consist (a set of locomotives) to each train in a preplanned train schedule so as to provide each [...]

Train units need regular preventive maintenance. Given the train units that require maintenance in the forthcoming one to three days, the rolling stock schedule must be adjusted so that these [...]

The impact of 1993 reform of the British railway industry on investments is examined.

The Association of American Railroads wished to determine the effect of a maintenance practice known as grinding on the occurrence of rail fatigue defects and on the subsequent total traffic usage before a track must be replaced. Because a designed experiment was not practical, an analysis of historical data from the Canadian Northern Railroad is presented. In the analysis, certain covariate data are available, specifically the amount of grinding and some physical characteristics of the rail; other important covariate data are not available, however. A model for the number of defects as a function of traffic usage is developed based on a modulated Poisson point process. The model incorporates the effect of the available covariates and a mixture of Dirichlet processes set-up for the scale parameters of the individual rail sections that allows an assessment of the overall effect of the unavailable covariates. The model is then used to determine an optimal replacement period for a whole rail track. The analysis demonstrates that grinding reduces the expected number of defects and increases the optimal replacement interval. KEY WORDS: Counting process; Markov chain Monte Carlo; Mixture of Dirichlet processes.

A Korean specialist analyzes the project designed to link the Trans-Siberian Railway (TSR) and Trans-Korean Railway (TKR), a project that is currently under active discussion in both Russia and South Korea. The significance of the TSR in relation to Russia's new strategy towards the Asia-Pacific region and the present conditions of international transit container traffic is examined. An evaluation is offered of the critical issues that need to be resolved to make the project a reality as well as implications of the project for economics and politics in the region if the project reaches completion.

Shippers decide to use particular transportation modes and carriers based at least partially on their perceptions of the services provided.(1) An example of this relating to intermodal rail-truck service was [...]

John Bates Clark, Arthur Hadley and H.C. Adams, economists of the 19th century, were concerned about the rise and fall of the railroad industry, condemned laissez-faire orthodoxy and industrial competition, and supported the corporatist school of political economy's insistence on trust, cartels and monopolies in business. They also used their knowledge of the railroad industry to oppose market regulation of capital-intensive industries.

Putting Maglev on Track' (Issues, Spring 1990) observed that growing airline traffic and associated delays were already significant and predicted that they would worsen. The article argued that a 300-mile-per-hour […]

Byline: Gultekin Karadere, Osman Kopmaz, Emin Gullu This paper deals with the transient behaviour of two main parts of a clutch, i.e., friction plate and hub, in a passenger car, during engagement phase. The present work aims to develop a simple discrete model that might enlighten the vibrations of interior part of a clutch. The second part of the work is devoted to examining the effect of torsional stiffnesses, external loading torque, friction gradient and viscous damping on the transient behaviour of clutch parts along with other components. Case studies are carried out based on two different scenarios for clutch and gas pedals actions.

Byline: M. Ansari, E. Esmailzadeh, D. Younesian A comprehensive parametric study is performed on the longitudinal dynamics of a freight train based on different nonlinear time-domain models. The effect of different parameters, such as the couplers stiffness and damping, train speed, train acceleration, load distribution pattern, on the longitudinal train dynamics are investigated. Moreover, the effect of an empty wagon and its position, on the overall longitudinal train dynamics is discussed. A computer simulation model is developed to determine the optimum placement of the second locomotive in order to obtain the lowest longitudinal forces. Further study is carried out to determine the best type of automatic couplers.

Byline: Yuping He, John McPhee A method is presented for determining the critical speed of rail vehicles. Dynamic Mode Tracking (DMT) is used to identify the dynamic modes for a given speed and a Sequential Quadratic Programming (SQP) algorithm determines the critical speed at which the least-damped mode has zero damping. It is shown that the SQP algorithm without DMT often fails to find the critical speed. In comparison, the combined SQP-DMT algorithm provides a reliable identification of the critical speed. This integrated algorithm can be applied to rotor dynamics, wind turbine dynamics, aeronautics, and road vehicle dynamics for automatically identifying the critical speed corresponding to a linear stability analysis.

Byline: Yang-Tsai Fan, Wen-Fang Wu A 28-degree-of-freedom dynamic model is proposed to study the stability of rail vehicles and examine the impact load caused by wheel-flat. Different kinds of track irregularity are considered as random inputs. The stability of the vehicle is discussed in detail and compared with available full-scale test data. It is found that numerical simulation results are in good agreement with test data for a certain type of vehicle. Both of them indicate the transverse acceleration of the bogie meets the required stability criteria. It is also found that derailment will not occur when the vehicle runs at its regular service speeds.

The details pertaining to the construction of Betuweroute - a freight railway line, in Netherlands, linking the port of Rotterdam with European rail lines at the Dutch-German border, are presented.

Byline: Joao Pombo, Jorge Ambrosio A methodology to create 3D track models, including irregularities, is developed. A new method using wheel and rail surfaces parameterisations is applied to identify multiple contact points. This method allows lead and lag flange contact, required to study derailment and switches. The formulation can be used for any kind of wheel or rail profile and still be computationally efficient, without requiring lookup tables. The method is applied to study the ML95 vehicle in a straight track with experimentally measured track irregularities. The accuracy of this procedure is demonstrated with respect to selected results obtained by experimental testing and by ADAMS/Rail.