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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.