Rapid Transit Railway Research Articles

지방 도시 일반철도 역사 활용방안에 관한 연구 - 광주광역시 효천역, 서광주역을 중심으로 -

In South Korea, the railway facilities were once a symbol of modernization and a driving force behind urban growth, however, they encounter a period of decline as the occurrence of the overall changes in the transportation system. In particular, the number of passengers who use the rapid transit railway stations other than KTX stops has been significantly lowered, thus the plans to utilize those stations were sought continuously. Under the circumstance, the plan for utilizing the idle spaces of those stations as public rental housing for young people has recently been announced in the metropolitan area, but it is still a challenge to generalize the plan to local cities. In that regard, this study examined the rapid transit railway stations in Gwangju, thereby suggesting measures to utilize idle spaces around the stations. This study can be a reference when utilizing the stations of the urban outskirts, which are difficult to develop as a tourism resource because they are not combined with urban railways among the rapid transit railway stations of local cities with a small number of passengers and have no sufficient value as modern cultural heritage. In other words, it would be possible to utilize those railway stations by analyzing the characteristics of the wide-area and local-area for the places of the relevant station and inserting a strategic program suitable for the idle spaces of the station.

Electromagnetic interference measurement for axle counters light rapid transit railway in Indonesia

The measurement and analysis of electromagnetic interference (EMI) from light rapid transit (LRT) axle counters against magnetic field interference in Indonesia has been carried out. The low-cost magnetic sensors were developed according to the British Standard (BS) EN 50592:2016. The measurement setup and magnetic field limit were based on the British Standard EN 50592:2016 and ERA/ERTMS/033281 standard. Two frequency range of the measurements, lower and higher frequencies with two different train running mode, acceleration mode and deceleration mode were applied in this research. The results in lower frequency range (10 to 100 kHz) were very close to the limit value in both acceleration and deceleration mode, especially at the 30 to 50 kHz for the y and z directions. Although there may possibly magnetic interference at low frequencies, most of the magnetic field emissions were still in acceptable range.

Daily Mobility in Urban Peripheries: The Role of Clandestine Taxis in Dakar, Senegal

Background: This study addresses the mobility practices of the inhabitants of the peripheries of Dakar and the transport services they use to meet their mobility needs, in particular the unlicensed shared taxis (“Clandos”). In the peripheries, which suffer from a lack of jobs and amenities, mobility is essential to meet household needs and for social integration. Current transport policies focus on formalizing supply and organizing the system around high-capacity transport facilities, such as the Regional Express Railway (TER) or Bus Rapid Transit (BRT), but they have difficulty in dealing with the mobility problems facing the outskirts of the city. Methods: The study is based on secondary analysis of the 2015 Household Travel Survey and on a survey on the activity of Clandos conducted in 2021 in Dakar. Results: The analysis highlights the daily mobility practices of the inhabitants of the peripheral areas. These residents, who are on average poorer than the others, travel mainly on foot. Their access to public transport remains limited and, when they use it, a significant proportion of their trips are made by Clando. Clandos have a dual function. On one hand, they are used for long trips to the center, in competition with buses, but more often they operate as a complement to buses. On the other hand, they are mostly used for local mobility within the peripheries. Conclusions: Although relatively expensive, Clando services are valuable for the inhabitants of the peripheries and their daily mobility. They should be better integrated into transport and planning strategies for the peripheral areas.

Improving Early Stakeholder Engagement Process: An Empirical Study of Rapid Transit Railway of Malaysian Project

Stakeholders in infrastructure projects should be steadily engaged starting from the earliest stage of the project i.e pre construction, until completion of the project. Stakeholder which directly and indirectly engaged in a large infrastructure projects, has different desires, interests, rights, and also can be voiceful. The main purpose of engaging of with the stakeholder is to promote fairness and trustworthy both to the external and internal stakeholder because as individuals and groups who are excluded from the decision-making processes are unlikely not to have their needs and preferences reflected in the outcome. The purpose of the paper aims to focus on improvement on the process of stakeholder engagement in Malaysian railway case study focusing on planning stage. This paper applies a qualitative research methodology based on semi-structured interviews and observation from a single case study of a mass rapid transit railway project in Malaysia. Empirical study from the case study will lead to establish lesson learned that could improve the stakeholder engagement scheme in infrastructure projects. The findings explained the sequence by showing the improvement of stakeholder engagement processes that need to be done during the pre-construction process. The suitable engagement process involves internal preparation and alignment, consulting, monitoring and planning. Albeit engagement process is a difficult to manage, it requires courage and humility when dealing with the public and community.

Solving real-size stochastic railway rapid transit network construction scheduling problems

We propose an iterated greedy matheuristic for efficiently solving stochastic railway rapid transit transportation network construction scheduling problems, where both the construction duration of the segments and the passenger demand rate of increase are stochastic. The network construction scheduling problem consists of sequencing the construction of lines of a urban transportation network with the aim of maximizing the discounted long-term profit of the project. This problem can be described as a resource-constrained project scheduling problem, where both the budget and the available construction equipment act as resources influencing the schedule. We consider that partial lines can be put into operation as soon as they are finished, thus benefiting users with a partial and quick usage of the network infrastructure. This assumption makes both the costs and the revenues dependent on the schedule. After analyzing some characteristics of the best solutions, we propose an iterated greedy matheuristic for solving the stochastic version of real-size network construction scheduling problems. To illustrate our methodology we apply the algorithm to the construction of the full metro network of the city of Seville.

Noise assessment of elevated rapid transit railway lines and acoustic performance comparison of different noise barriers for mitigation of elevated railway tracks noise

Subways or rapid transit railways can be found in many major cities. These rapid transit railways are typically built above ground whenever possible to avoid the high capital cost of tunneling and also the high running cost of air conditioning and ventilation. However, noise from trains running on elevated tracks or viaducts close to residential and commercial buildings or houses is a problem for many cities. Noise barriers have been used extensively to mitigate noise from motorways, heavy trunk roads, and construction sites. On the other hand, relatively few reported studies on the design and performance of noise barriers for elevated railway tracks or viaducts to mitigate rapid transit train noise. The effectiveness of noise barriers on elevated railway tracks or viaducts for the mitigation of train noise may be different and challenging to predict due to complex street canyons and surrounding buildings beside the barrier designs and construction materials. Riding on the Singapore Railway Noise Barrier Programme, the present research conducted on-site measurements of several housing estates in Singapore to investigate the effect of noise barriers on the mitigation of train noise. Comparisons were also carried out to examine the performance of two different designs, Taiwan's Taipei subway track noise barriers and the vertical noise barriers used by the Singapore Mass Rapid Transit (MRT) system. Acoustic mapping revealed that the simulated noise mitigation barriers led to a 5–12 dB(A) reduction in noise levels reaching the resident apartments.

A quantitative approach for the long-term assessment of Railway Rapid Transit network construction or expansion projects

One of the main issues to address in the analysis of a public railway rapid transit network construction project is the assessment of expected revenue and cost. On a network topology already defined, the problem considered in this paper consists on finding the construction schedule that maximizes the project long-term net profit, not only deciding on the construction schedule and the network operation but also determining the subsidy to compensate the service operator along the considered long-term planning horizon. Aiming at early attending the demand of citizens, partial pieces of the constructed lines are put into service as soon as they were finished. Hence, in order to determine a subsidy to compensate service operators from a possible non-profitable network operation, it is necessary to measure the variable operation costs that emerge along with the progressive enlargement of a connected network. Further, the problem can be viewed as a particular case of a multiple resource-constrained scheduling problem, where both, the budget and the construction equipment availability act as limiting resources. We propose a non-linear mixed integer programming model which is fully linearized and solved by using a two-phase branch-and-cut procedure. We illustrate the proposed methodology within a real case, the Metro network project of the city of Seville.

Fracture Modeling of the Bi‐Block Ballastless Track System Resulting from Early‐Aged Relative Humidity during the Construction Process

Drying‐induced cracks are an important issue for bi‐block ballastless track system consisting of foundation, precast sleepers, and cast‐in‐place track slab, which not only significantly affects the comfortableness and safety of rapid transit railway but also reduces the service life of ballastless track. In order to explore its damage mechanism, this work presents an evolution model of relative humidity (RH) in the CRTS I bi‐block ballastless track system by considering the actual construction sequence and environmental conditions to simulate the crack propagation induced by nonuniform RH field. Firstly, based on the node coupling technique, a three‐step transfer process of RH is designed to separately investigate the influence of the construction sequence on the early humidity field in the foundation, sleepers, and cast‐in‐place track slab, and then the nonuniform distribution of early humidity field in the ballastless track system is determined. Subsequently, the formation mechanism of shrinkage crack in the system is analyzed, and the crack propagation path is predicted by using the mixed‐mode fracture criterion. The results show that the maximum relative humidity gradient (RHG) appears at the interface between the track slab and the sleeper after concreting the cast‐in‐place track slab, which causes the maximum principal stress due to the drying shrinkage property of concrete materials. When the maximum principal stress exceeds the tensile strength of the interface, an interface crack will be generated and converted to a splayed crack with an initial angle of about 45° at the sleeper corner, which will be further propagated under the action of drying shrinkage deformation and finally forms a transverse through‐wall crack in the track slab. The simulated crack propagation path agrees with the observed one at the site well, and thus the results are beneficial to understand the formation mechanism of through‐wall crack in the track slab and further guide the construction design of the bi‐block ballastless track system.

The railway rapid transit network construction scheduling problem

We consider the problem of scheduling the construction of a railway rapid transit transportation network. We assume that the network topology is already known. The problem consists of sequencing the construction tasks in order to maximize the long term profit of the project. The problem can be viewed as a resource-constrained project scheduling problem, where both the budget and available construction equipment act as resources influencing the schedule. Since lines segments can be put into operation as soon as they are finished, both the costs and the revenues are dependent on the schedule. We propose a quadratic integer programming model which is solved to optimality by branch-and-cut. To illustrate the methodology we apply the model to the construction of the Metro network of the city of Seville, and we perform sensitivity analyses on several model parameters.

Integrated Railway Rapid Transit Network Design and Line Planning problem with maximum profit

We solve the Integrated Network Design and Line Planning Problem in Railway Rapid Transit systems with the objective of maximizing the net profit over a planning horizon, in the presence of a competing transportation mode. Since the profitability of the designed network is closely related with passengers’ demand and line operation decisions, for a given demand, a transit assignment is required to compute the profit, calculating simultaneously the frequencies of lines and selecting the most convenient train units. The proposed iterative solving procedure is governed by an adaptive large neighborhood search metaheuristic which, at each iteration, calls a branch-and-cut algorithm implemented in Gurobi in order to solve the assignment and network operation problems. We provide an illustration on a real-size scenario.

The Railway Rapid Transit frequency setting problem with speed-dependent operation costs

In this paper we deal with the problem of determining the best set of frequencies in a Railway Rapid Transit network considering convex non-linear variable operation costs at segments. The operation cost at each track will depend on the train model characteristics operating each line, the passenger load on trains and the average train speed. Given the network topology and the passenger mobility patterns, we propose a methodology to determine the best regular timetable, taking into account both, users’ and service provider points of view. Since the frequency setting and the passengers assignment are intertwined problems, the proposed procedure solves a succession of interrelated transit assignments and frequency setting models. At each iteration, given a transit assignment, the resultant frequency setting problem turns into a Mixed Integer Non-Linear model which is solved to optimality in a sequential way, both considering the different train models and the passenger load on trains. The proposed methodology is illustrated on a real-size scenario.

Measuring the Accessibility of Railway Stations in the Brussels Regional Express Network: a Node-Place Modeling Approach

As a result of mounting concerns over the adverse ecological and socio-economic effects of mobility systems dominated by individual motorized transport, metropolitan areas worldwide have expressed a renewed interest in the role of public transport. Like many other metropolitan areas, the Brussels Capital Region (BCR) faces the problem of an increasingly congested transport system. Against this backdrop, the Regional Express Railway (RER) network is intended as a rapid-transit railway system serving an area of 30 km around the region, with the objective of improving the capacity and frequency of the railway services between the BCR and its periphery. In order to inform policy prescription, this paper reports on a systematic empirical assessment of all RER railway stations in terms of transport and land use characteristics, by drawing on the node-place modeling and transit oriented development literature. The proposed accessibility instrument considers different catchment area sizes in order to increase its empirical basis. Based on this systematic railway station inventory, cluster analysis was conducted revealing seven comparative accessibility profiles, of which some prove highly robust over the different precinct sizes. When combining the quantitative analyses reported in this paper with the more intuitive expertise of practitioners and stakeholders involved in the planning process, the accessibility instrument may effectively assist the identification of differentiated development opportunities for the RER stations.

A study on an analysis model for the thermo-mechanical behavior of a solid disc brake for rapid transit railway vehicles

One of the primary interests in the railway field is to improve speed as well as to secure the safety of railway vehicles at a high speed. In light of this, the demand for braking systems that offer improved performance and safety has also been growing consistently. The braking system is a critical element directly connected with safety. In order to secure reliability and establish the maintenance standard for the braking system, it is necessary to secure an accurate evaluation technology. As the braking disc of the braking system is very sensitive to safety and maintenance, a method to evaluate thermal cracking must be developed. Because the brake disc goes through a repeated process of heating and cooling due to the friction energy and the heat convection, respectively, in every braking action, it is subject to thermal fatigue. As well, the partial contact area caused by friction between disc and pad during the braking process results in thermal distortion, causing a hot band and a hot spot. This thermal distortion may also cause thermal cracking on the friction surface. The aim of this research was to find the cause of thermal cracking through a thermo-mechanical friction analysis of disc and pad, and to verify the analysis model through the dynamo machine.

The integrated rolling stock circulation and depot location problem in railway rapid transit systems

Rolling stock management is one of the key operational issues for a railway transportation company. It constitutes the fourth phase of the classical Railway Planning Process, after Network design, Line Planning and Services Scheduling/Timetabling. Rolling stock circulation consists of defining individual train paths over the network accomplishing pre-defined services. Those services are previously designed in order to attend certain passengers’ demand, and fulfilling some design criteria. In this paper we propose, in the context of Railway Rapid Transit Systems, a general mixed integer programming model in order to design rolling stock circulation plans and simultaneously considering the problem of determining the number and location of rest facilities. The model yields then rolling stocks plans that facilitate the posterior design of rotating maintenance schemes. According to the problem structure, we propose a sequential solving approach. We first determine the minimum number of vehicles needed to perform the complete weekly train schedule. In a second phase, we obtain the set of daily routes that must be performed at each line every day. In a third stage, we deal with the problem of determining weekly circulations and depot locations by means of a Genetic Algorithm. The objective at this stage is to minimize empty movements and to equilibrate the number of kilometers covered by each unit. In order to illustrate the proposed approach, this is applied to design a rotating rolling stock plan for the RRT Network of Seville.

Design of energy-Efficient timetables in two-way railway rapid transit lines

A methodology to design energy-efficient timetables in Rapid Railway Transit Networks is presented. Using an empirical description of the train energy consumption as a function of running times, the timetable design problem is modelled as a Mixed Integer Non-Linear optimization problem (MINLP) for a complete two-way line. In doing so, all the services in both directions along a certain planning horizon are considered while attending a known passengers’ demand. The MINLP formulation, which depends on train loads, is fully linearised supposing train loads are fixed. A sequential Mixed Integer Linear solving procedure is then used to solve the timetabling optimization problem with unknown train loads. The proposed methodology emphasizes the need of considering all the services running during the planning horizon when designing energy-efficient timetables, as consequence of the relationship among train speeds, frequency and fleet size of each line. Moreover, the convenience of considering the energy consumption as part of a broad objective function that includes other relevant costs is pointed out. Otherwise, passengers and operators could face up to an increase in the whole cost and a decrease in the quality of service. A real data scenario, based on the C-2 Line of the Madrid Metropolitan Railways, is used to illustrate the proposed methodology and to discuss the differences between the energy-efficient solutions and those obtained when considering operation and acquisition costs.

Integrated approach to network design and frequency setting problem in railway rapid transit systems

This work presents an optimization-based approach to simultaneously solve the Network Design and the Frequency Setting phases on the context of railway rapid transit networks. The Network Design phase allows expanding existing networks as well as building new ones from scratch, considering infrastructure costs. In the Frequency Setting phase, local and/or express services are established considering transportation resources capacities and operation costs. Integrated approaches to these phases improve the transit planning process. Nevertheless, this integration is challenging both at modeling and computational effort to obtain solutions. In this work, a Lexicographic Goal Programming problem modeling this integration is introduced, together with a solving strategy. A solution to the problem is obtained by first applying a Corridor Generation Algorithm and then a Line Splitting Algorithm to deal with multiple line construction. Two case studies are used for validation, including the Seville and Santiago de Chile rapid transit networks. Detailed solution reports are shown and discussed. Conclusions and future research directions are given.

An adaptive neighborhood search metaheuristic for the integrated railway rapid transit network design and line planning problem

We model and solve the Railway Rapid Transit Network Design and Line Planning (RRTNDLP) problem, which integrates the two first stages in the Railway Planning Process. The model incorporates costs relative to the network construction, fleet acquisition, train operation, rolling stock and personnel management. This implies decisions on line frequencies and train capacities since some costs depend on line operation. We assume the existence of an alternative transportation system (e.g. private car, bus, bicycle) competing with the railway system for each origin–destination pair. Passengers choose their transportation mode according to the best travel times. Since the problem is computationally intractable for realistic size instances, we develop an Adaptive Large Neighborhood Search (ALNS) algorithm, which can simultaneously handle the network design and line planning problems considering also rolling stock and personnel planning aspects. The ALNS performance is compared with state-of-the-art commercial solvers on a small-size artificial instance. In a second stream of experiments, the ALNS is used to design a railway rapid transit network in the city of Seville.

Setting lines frequency and capacity in dense railway rapid transit networks with simultaneous passenger assignment

We propose a Mixed Integer Non-Linear Programming (MINLP) model in order to determine optimal line frequencies and capacities in dense railway rapid transit (RRT) networks in which typically several lines can run over the same open tracks. Given a certain demand matrix, the model determines the most appropriate frequency and train capacity for each line taking into account infrastructure capacity constraints, allocating lines to tracks while assigning passengers to lines. The service provider and the user points of view are simultaneously taken into account. The first one is considered by selecting the most convenient set of frequencies and capacities and routing passengers from their origins to their destinations while minimizing the average trip time. The second one by minimizing operation, maintenance and fleet acquisition costs. Due to the huge number of variables and constraints appearing in real size instances, a preprocessing phase determining the best k-paths linking origin and destination stations is followed. Then, the best paths are used to define sparse index sets in order to drastically reduce the size of the problem. As illustration, the model is applied to a simplified version of the Madrid Metropolitan Railway network.

Corporate sustainability and customer loyalty: the case of the railway industry

Introduction of the mass rapid transit railway system through the Gautrain has not only addressed the transport issue in South Africa but has also motivated and promoted the country’s economic growth by creating employment. Despite the increase in research focusing on the importance of the Gautrain to the South African economy, the influence of perceived convenience, image and safety on commuter satisfaction and loyalty in the South African mass rapid transit railway system context is still limited. This paper used a data collected from 206 Gautrain commuters in the Gauteng province of South Africa to examine the interplay between perceived convenience, image, safety, commuter satisfaction and loyalty. Smart PLS software technique was used to statistically analyse the measurement and structural models. The results revealed that perceived convenience, image and safety positively influenced commuter satisfaction, which, in turn, influenced commuter loyalty. These results may be used by marketers in mass public railway systems to initiate strategies intended to increase both commuter satisfaction and loyalty

고속철도시스템에서 낙뢰로 인해 전차선에 유도되는 서지전압의 해석

Lightning is one of hazards affecting the rapid-transit railway system. There are two effects, which are direct lightning surge to electric car line and induced lightning surge. Protection methods for the direct lightning surge are studied with various occasions, however, study of induced lightning surge is insufficient in spite of a large or small effects. In this paper, it is analysed the way that serge voltage is induced to electric car line by lightning strikes. By modeling the propagation process and the coupling phenomenon of electromagnetic wave produced by lightning strikes, it is achieved to make integrative circuit model combined with existing electric car model. The study is conducted into three different waveform of electromagnetic wave produced by lightning; rectangular wave, double exponential distribution wave, triangle wave. It is also simulated that the inducing serge is coupled to electric car line in an arbitrary location. The simulation results in that, when rapidly changing rectangular wave is supplied, maximum power is induced to electric car line.