Passenger Rail Line Research Articles

VibraSIG - Modeling railway structure-borne noise and vibrations and implementation in QGIS geographic information software

In the context of engineering studies for passenger rail line projects, a method for predicting vibration and structure-borne noise levels in buildings close to the line is needed on the scale of a town or territory. ACOUSTB has developed VibraSig, a method for calculating railway vibration and structure-borne noise, based on two numerical models (VibraFer, CSTB and MEFISSTO, CSTB). A numerical model in VibraFer is used to define a railway excitation source term. A numerical model in MEFISSTO is used to calculate the vibratory response of the tunnel and the ground up to the building on a cross-section. A statistical building response model is used to estimate structure-borne noise and floor vibration levels. Finally, the method for predicting vibration and structure-borne noise levels is extended to the entire project route, and the results are visualized for each building on a Geographic Information System (GIS).

Prediction of railroad track geometry change using a hybrid CNN-LSTM spatial-temporal model

Track geometry is highly important for ensuring railroad safety. Predicting track geometry degradation can support preventive maintenance by identifying and prioritizing track segments that are more prone to potential track geometry defects. This paper develops a novel machine learning approach that can simultaneously geospatially align track geometry data from multiple inspections accounting for positional errors, and also predict foot-by-foot track geometry change over time. The proposed position correction method considers multiple geometry parameters to provide highly accurate positional information for geometry measurements, which is a prerequisite for foot-by-foot track geometry prediction. A hybrid CNN (convolutional neural network)-LSTM (long short-term memory neural network) machine learning model is developed to account for spatial–temporal dependence with respect to foot-by-foot track geometry change. Specifically, CNN is used to incorporate spatial dependence of track geometry on adjacent segments. LSTM is applied to learn dynamic changes in track geometry data over time to consider the temporal dependence. The hybrid CNN-LSTM model is validated using track inspection data provided by one major freight railroad in the United States. The results show that our positional error correction method can reduce the relative positional error to less than 1 foot with a 99% confidence interval. Our proposed CNN-LSTM model outperforms four other models, including a naïve model (using the last observation), multi-layer perceptron (MLP), plain CNN, and plain LSTM, for both short-term and long-term prediction periods. The proposed hybrid machine learning methodology can be adapted to various other freight and passenger rail lines. The predictive track geometry change information can be used by the industry to plan and prioritize resources for preventative maintenance, yielding benefits in safety and operational efficiency.

Integration of Train-Set Circulation and Adding Train Paths Problem Based on an Existing Cyclic Timetable

With the aim of supporting the process of scheduling a hybrid cyclic timetable and adapting traffic needs, this paper is concerned with inserting additional train paths problem for tactical and short-term planning applications with multiple objectives. Focusing on an existing cyclic timetable on a high-speed passenger rail line, the problem is to minimize both the total adjustments for initial trains and the number of required train-sets. The timetable scheduling, train-set planning and rescheduling are three complex optimization problems respectively and usually solved in a sequential manner. In this paper, these phases are integrated in a mixed integer programming model, and the multi-objective adding train paths (ATP) model is proposed, which decides simultaneously initial trains’ modifications, additional trains’ schedules and train-set circulation. The tolerance of disruption for initial trains including allowed adjustment and periodic structure is taken into account in light of the practical concerns. The difficulty of this integrated problem is that train-sets circulation is usually determined after all of the train lines and timetable have been fixed. However, in the adding train paths problem, the additional trains do not exist in the initial timetable. In order to solve the problem in a reasonable time, a relaxation approach to the adding paths problem is presented. We start from fixed train-set route, and then apply flexible train-set route that provides possible alternative turning activities to decrease the number of required train-sets. A case study based on Shanghai-Hangzhou high-speed rail line in China illustrates the methodology and compares the performance of various settings of perturbation tolerance, time window and train-set applications.

The use of focus groups to foster stakeholder engagement in intercity passenger rail planning

Recent changes in the United States (U.S.) passenger rail policies have affected a number of National Railroad Passenger Corporation (Amtrak) corridors. One of the major changes is that, since the Passenger Rail Investment and Improvement Act (PRIIA) of 2008 was passed, all short-distance Amtrak corridors should become state-supported. Stakeholder and public involvement is strongly advocated by the U.S. Department of Transportation as a fundamental component of the transportation planning process and an important step to keep the public informed and engaged in decision making. Thus, states should attempt to engage the public in any funding decisions that might affect passenger rail service changes (such as line discontinuance). In addition, states should seek the input of the stakeholder and public to evaluate the alternative transportation investment options available in case such service changes occur. Nevertheless, both literature and practice of stakeholder engagement on policy making and planning of strategic operational changes and/or other broader decision making is scarce.This article presents a case study of stakeholder engagement in transportation decision making pertaining to decisions of investments in passenger rail and state and local fund allocation, using a focus group approach. This engagement aimed to (1) consult stakeholders in a group setting in an attempt to produce shared knowledge and (2) explore how the transportation investment decision-making process can incorporate public preferences and community values in a participatory manner via the assessment of potential investment directions. The goals of the study are to explore whether stakeholder engagement at a smaller-size projects and/or broader policy and planning decision making can be beneficial, and whether focus groups are suitable to facilitate such engagement.The findings verify that stakeholder involvement can provide states and other decision-makers with valuable insights on several topics supporting future policy and funding decisions. For example, in the case explored, the engagement of the stakeholders revealed that public investments towards the continuation and potentially improvement of the intercity passenger rail services are in line with the communities’ goals and are viewed as more beneficial than alternative transportation investments that can enable mobility in the area. In addition, the findings suggest that the benefits of engaging stakeholders in transportation decision making go beyond the act of gathering stakeholders’ input; focus groups or similar dynamic forums can facilitate the production of innovative ideas and shared knowledge while fostering collegiality among stakeholders. Finally, the findings of the case study also verify that focus groups can be a suitable approach to engage and consult a small group of stakeholders for higher-level transportation investment decision making. Overall, the case study results indicate that stakeholder engagement can benefit smaller-size projects and/or broader policy and planning decision making, such as decisions involving the financing of an intercity passenger rail line and investment directions towards operational changes of the line and/or alternative transportation modes and infrastructure.

Laboratory Study and Evaluation of the Loess Liquefaction under Random Seismic Loading

By using the DSD-160 dynamic triaxial apparatus, liquefaction experiments under random seismic loading of the saturation original samples from a passenger rail line which located in the loess tableland in china was tested. Based on the test results, connected with the forecasting method of the liquefaction test under random seismic loading and the results of seismic hazard analysis, the liquefaction potential of the saturation loess from different regions in the passenger rail line is distinguished. Moreover, the predictions include 50 years probability of exceedance 10% and 2%of the loess liquefaction potential of the sites mentioned above is obtained.

High‐Speed Rail: Lessons for Policy Makers from Experiences Abroad

In April 2009, the U.S. government unveiled its blueprint for a national network of high‐speed passenger rail (HSR) lines, aimed at reducing traffic congestion, cutting national dependence on foreign oil, and improving rural and urban environments. In implementing such a project, it is essential to identify the factors that might influence decision making and the eventual success of the HSR project, as well as to foresee the obstacles that must be overcome. The authors review, summarize, and analyze the most important HSR projects carried out to date around the globe, focusing on the main concerns of HSR projects: their impact on mobility, the environment, the economy, and urban centers. The authors identify lessons for policy makers and managers who are implementing HSR projects.

Experimental Study on the Anisotropic Properties of Undisturbed Loess

Loess has been subjected to long-term deposit, geological structure and weathering under the condition of self-weight and above covered load. Accordingly, it would result in many vertical joints and differences in mechanical response and deformation properties for vertical and transverse. In order to obtain different mechanical properties of vertical and transverse, laboratory physical mechanics tests (collapsible test, consolidation test, direct shear test, triaxial compression test and unloading test) were carried out to investigate typical Q3 loess from field above He Jia-zhuang tunnel of Huang Tu-liang district on Zhengzhou-Xi’ an high-speed passenger rail line in China. The results suggest obvious anisotropic properties of undisturbed loess. Not only do the conclusions supply theoretical foundation for design and construction of tunnel in loess, but also can act as guiding reference for similar underground engineering.

Model Test and Numerical Simulation for Support Time of Tunnel in Loess

The work presented in this paper focuses on support time for tunnel, which has much effect on stability of tunnel. Based on loess tunnel of Zhengzhou-Xi’an high-speed passenger rail line in China, large scale model test with geometric proportion 1: 20 was applied to study on different support time. Supplemental numerical analysis was carried out to investigate the effect of release ratio of stress which cannot be covered by model test. It is revealed that it is asynchronous change for deformation, strain and stress of surround rock. If the supporting constructs prematurely, internal force of support would be excessive greatly and if the supporting constructs too late, it will bring excessive slack pressure which leads to the plastic zone unfavorable, even tunnel collapse. The reasonable support time can improve self-bearing capability of surrounding rock and reduce the cost. The limited displacements about 17.8 cm for crown and 12.9 for horizontal convergence are gained. The research results can act as reference for similar materials tunnel and underground engineering construction.

Model test for dynamic construction mechanical effect of large-span loess tunnel

It has been a focus of debate for a large time on construction methods for large-span loess tunnel. Reasonable construction method has much effect on stability of tunnel and construction schedule. Deformation and failure of surrounding rock are quite complex. Associating with the large-span loess tunnel of Zhengzhou—Xi’an high-speed passenger rail line in China, large scale model test with geometric proportion 1:20 is applied to study on dynamic mechanical behavior of various construction methods. They include full-face excavation with support and no support, and benching method with support. It is found that pre-deformation and stress accumulation take place ahead of working face. The effects of three construction methods are further studied, particularly in terms of tunnel displacement and stress changes. It is revealed that benching method transfers load to an unexcavated area, limits horizontal deformation, reduces stress concentration effectively, lengthens the distance between location of peak for stress concentration and working face, and consequently increases stability. The model test results not only supply theoretical foundation for determination of reasonable construction method, but also can act as reference for similar tunnel and underground engineering construction.

Impact of ground subsidence on the Beijing–Tianjin high-speed railway as mapped by radar interferometry

The construction of the Beijing–Tianjin high-speed railway line started in July 2005. The railway has been completed and opened to traffic in August 2008, just before the Beijing Olympic Games. The 113 km railway costing 13.3 billion Yuan (US $1.5 billion) is the country's first high-standard passenger rail. It is also believed to be the pilot project of a massive high-speed rail network in China. The train shuttles passengers between the cities in just half an hour, 45 minutes shorter than the usual travel time. The train is designed to go 200 km/h, but can reach speeds of 350 km/h. The current railway is under pressure, handling 25.55 million passengers each year. The new passenger rail line is expected to handle 32 million passengers from 2008 and 54 million passengers in 2015. Both Tianjin and Beijing have been suffering from ground subsidence due to groundwater extraction. This study focuses on mapping the impact of such subsidence on the Beijing–Tianjin high-speed railway using differential radar interferometry. Both persistent scatterer interferometric synthetic aperture radar (PSInSAR) and differential InSAR (DInSAR) techniques are used to analyse SAR data collected by ENVISAT ASAR and ALOS PALSAR sensors. The results are further analysed in GIS and compared with reported ground survey results.

Regional Rail

As the extent of North American commuter rail systems increases, interest increases in developing new services to connect with existing and established passenger rail lines. Some new systems under consideration rely on timed transfers between low-frequency routes so that some or all passengers may reach their ultimate destinations. The paper summarizes six North American services that rely on connections and planning reports for two potential new services. It draws general observations and recommendations for the design of other new services and suggests general findings and guidelines for the design and operation of the commuter rail transfer operations. First, most branch-line connecting services tend to offer the greatest economic utility as service supplements during off-peak periods. Second, attractive and economical connecting services are easier to schedule and manage when the branch is very short. Third, it is difficult for a single consist (train set) to provide optimal connections in both directions. Fourth, when trade-offs between convenient inbound and outbound connections must be considered, schedulers nearly always favor the quality of the outbound connection over that of the inbound connection. Fifth, the scheduling of evening outbound connections often entails a load-and-go type of operating regime. Finally, the quality of branch-line connecting services is affected by the reliability of the main-line service.

Bicriteria train scheduling for high-speed passenger railroad planning applications

This paper is concerned with a double-track train scheduling problem for planning applications with multiple objectives. Focusing on a high-speed passenger rail line in an existing network, the problem is to minimize both (1) the expected waiting times for high-speed trains and (2) the total travel times of high-speed and medium-speed trains. By applying two practical priority rules, the problem with the second criterion is decomposed and formulated as a series of multi-mode resource constrained project scheduling problems in order to explicitly model acceleration and deceleration times. A branch-and-bound algorithm with effective dominance rules is developed to generate Pareto solutions for the bicriteria scheduling problem, and a beam search algorithm with utility evaluation rules is used to construct a representative set of non-dominated solutions. A case study based on Beijing–Shanghai high-speed railroad in China illustrates the methodology and compares the performance of the proposed algorithms.