Optimization of inverter placement for mass rapid transit systems using genetic algorithm

This paper is to investigate the proper expansion planning of traction substations (TSS) for an electrified mass rapid transit (MRT) system. The motion equation of train sets is used to solve the mechanical power consumption at each time snapshot according to the operation timetable, the passenger ridership and various types of operation resistance. The mathematical models of power converters in traction substations for different operation modes have been derived. With all train sets operated along the main line, the AC/DC load flow analysis is performed to find power demand of all traction substations for annual system peak operation over the study period. The objective function is formulated by considering both the voltage drop of train sets and investment cost of traction substations as the equivalent cost of all feasible states of each year. By performing the dynamic programming (DP) to minimize the objection function, the expansion planning of traction substations to achieve the minimum overall cost has been obtained by identifying the optimal capacity and locations of new traction substations to be committed at each year.

As cities grow in size, the vehicular trips on roads increase substantially. This necessitates adopting strategy to debilitate private transit modes and support public transport once the traffic volume level along any transit corridor in one way surpasses 8000 people for every hour. The introduction of a rail based Mass Rapid Transit System (MRTS) or Bus Rapid Transit System (BRTS) becomes essential. It has been observed that in developed countries, making arrangements for mass transit system start when population of city surpasses 1 million, and the system is in position when the city population is 2–3 million and once the population exceeds 4 million planned extensions to the MRTS are quickly taken up. Both the mass transit systems are taken into consideration and compared for analyzing the benefits and limitations of the systems. The comparative analysis was done by considering different BRTS and MRTS. In terms of investment, the both systems are very costly. In terms of environmental impact, the MRTS is more effective than BRTS. It was also observed that if Intelligent Transportation System is incorporated the service of both systems may result in enhanced efficiency. It can be stated that the combination of various public transportation systems should be planed during the stages of design considering the integrated approach as a need for good public transportation system

As one of the primary business centers of China, Guangzhou has been undergoing rapid growth and expansion. Over the past decade, the Guangzhou Municipality Government has significantly upgraded its transport infrastructure, especially with the highly beneficial expansion of its Subway Mass Rapid Transit (MRT) system. Positive steps have also been taken to continue planning the construction of new roads, a Bus Rapid Transit (BRT) system and other transportation facilities. Further administrative and regulatory measures have also been implemented to control the situation, such as the banning of motorcycles from the central city area and the limitation of new automobile registrations. However, Guangzhou continues to face serious challenges of traffic congestion in and around the city center owing to further intensification of its population with economic growth. The need to ease Guangzhou’s stretched public transportation resources, and at the same time to support the realization of its “Eastward Advance” strategy, presents a unique challenge and opportunity to develop an advanced high-efficiency public transportation modality for Guangzhou, viz. the Group Rapid Transit (GRT) involving the use of automation-guided (driverless) smart-vehicles. This paper outlines the PRT/GRT (PRT: Personal Rapid Transit) smart-vehicle modality and also puts forth a proposal of Guangzhou’s first GRT route as the city’s first dedicated transportation link to the scenic landscape of the Eastern Tourism Zone. This GRT route will help in diffusing the city’s traffic congestion as well as support the effectuation of Guangzhou’s “Eastern Expansion” strategy, supplementing the ongoing expansion of the Guangzhou Municipality’s subway MRT networks.

The global population growth increased by 0.88% at the end of 2022 compared to the previous year. Jakarta and Singapore, as two densely populated areas in Southeast Asia, need to pay extra attention to the need for infrastructure, including adequate transportation systems. One of the prominent transportation modes in both regions is Mass Rapid Transit (MRT). MRT is an urban rail-based transportation mode aimed at providing regular and sustainable public services. The MRT system excels in capacity, speed, and reliability compared to other transportation modes, as it operates on fully separated tracks. Despite both regions having MRT systems, there are differences in several aspects. This research is conducted using a qualitative method, applying techniques such as the analysis of literature. The differing aspects between the Jakarta MRT and the Singapore MRT are headway (time between trains) and payment methods. The Singapore MRT has a smaller headway compared to the Jakarta MRT. The shorter the time, the better the service. In terms of payment methods, the Singapore MRT predominantly implements a cardless payment system, in contrast to the Jakarta MRT. The Jakarta MRT still offers the purchase of Single Trip Tickets and Multi Trip Tickets.

Mass rapid transit (MRT) systems are the backbone of transportation infrastructure in many cities. During emergencies, indoor subway stations become particularly susceptible to panic and overcrowding, making evacuation difficult. Therefore, simulating the evacuation and sheltering processes of a large number of individuals during emergencies is key in urban disaster response. In this study, a spatial evacuation risk model was used to enhance the safety of evacuation strategies in an MRT system. Data were collected on spatial architectural floor plans, and a database for communication and pedestrian flow was established. The behavioral patterns and distribution of individuals within stations and the characteristics of refuge spaces were also investigated. To simulate the processes of evacuation and sheltering, the Pathfinder evacuation simulation tool was used to construct a three-dimensional spatial model of a subway station. Specific scenarios were then constructed to simulate the procedures of evacuation and sheltering. Subsequently, the factors contributing to overcrowding-related hazards were analyzed to examine the spatial risks associated with crowd aggregation and evacuation and provide recommendations for improvement. Given its numerous advantages, this approach can serve as a valuable reference for conducting risk assessments in other large-scale crowd aggregation spaces.

This paper deals with the application of a heuristic-based evolutionary algorithms (EAs) on a specific industrial problem - the scheduling of rapid transit systems. The system under consideration is a medium-sized mass rapid transit (MRT) system and the dual objectives of minimizing operating costs and passenger dissatisfaction are considered. Making use of concepts such as Pareto-optimality and multiobjective evolutionary algorithms, the authors applied a multiobjective evolutionary algorithm (MOEA) to solve the problem. Comparison studies were done with current method, obtaining satisfactory results.

The asymmetric effects of gasoline prices on public transportation use in Taiwan

A genetic algorithm (GA) is proposed to optimise train movements using appropriate coast control that can be integrated within automatic train operation (ATO) systems. The coast control output for a train changes with the interstation distances and gradient profiles, and the current operating conditions of the mass rapid transit (MRT) system, namely, (i) train schedules, (ii) expected passenger loads and (iii) expected track voltages. The algorithm generates an optimum coast control based on evaluation of the punctuality, riding comfort and energy consumption. Before the train sets off to the designated station, a coast control table is generated that will be referenced by the train at runtime for deciding when to initiate coasting or resume motoring control. Each coast control table is encoded into variable length chromosomes with each gene representing the relative position between stations where coasting should be initiated or terminated. Each generation is evolved from mating of the paired equal-length chromosomes with possibilities of crossover, mutations, gene duplications and gene deletions. The key feature of this method is that it has a solid mathematical foundation. Effectively, the implementation provides good, credible and reasonably fast solutions for this variable dimensional and multiobjective optimisation problem. The algorithm has the potentials for on-line implementation for producing the coast control lookup table for each interstation run before the train sets off. The results, although preliminary, suggest that the method is promising.

The progressive industrialisation and urbanisation of urban areas have significantly altered hydrological factors such as terrain, imperviousness, and surface flow. These developments, accompanied by increased traffic congestion and carbon emissions, contribute to climate change. Consequently, implementing Mass Rapid Transit (MRT) systems is crucial for alleviating traffic congestion and reducing carbon emissions globally. However, the changes in urban hydrology following development, combined with increased rainfall due to climate change, exacerbate risks of flooding, erosion, and sedimentation for the MRT development and surrounding low-lying areas. Therefore, researching urban drainage systems under climate change conditions for MRT development is essential. This study utilised 1D/2D hydrodynamic modelling and simulation to investigate the performance of an existing MRT drainage system designed with a control-at-source concept and a new sustainable drainage system incorporating infiltration engineering and flow-retarding techniques, including porous layers and a bioecological system to mitigate urban flooding erosion and sedimentation. The results show that the new sustainable drainage system, featuring permeable pavements and bioretention facilities, effectively integrates 30% of the MRT-developed land typology without requiring additional land acquisition, which is cost-effective and practical for mitigating major flooding and reducing total suspended solids, thereby controlling erosion and sedimentation.

A number of studies have examined the impact of mass rapid transit (MRT) systems, especially the transit station, on house prices, and the conclusions vary. While most studies focused on the analysis at an aggregate level, this paper develops a hierarchical hedonic price model of individual growth to investigate the effects of real estate’s proximity to the train stations, together with other house/neighborhood-specific characteristics, on the longitudinal growth pattern of house prices in Great Taipei. Sample houses are those located within a radius of one kilometer from selected MRT stations. The empirical results show that: (1) the growth pattern of housing price in real terms over time is significantly upward; (2) the city in which the house is located and the type of building positively moderate such growth trajectory; and (3) the influences of both the distance to MRT on house prices and on the growth pattern of house prices are insignificant. Discussion and implications of these findings were provided.

Singapore is one of the most densely populated countries in the world. In this land-scarce city-state, public transport plays a crucial role in reducing road congestion, with the Mass Rapid Transit (MRT) system serving as a key component. The Circle Line (CCL) is one of the major lines within the MRT network, designed to connect key points across the island and improve overall transit efficiency. To complete the orbital loop of CCL, three new stations (Keppel, Cantonment and Prince Edward) between Harbour Front and Marina Bay stations are planned. However, the area around the three stations is heavily developed, posing significant challenges for underground construction. This paper presents the construction of a 52 m-long underground linkway at Keppel Station. This underground linkway was proposed to connect one of the entrances to the station’s main box. This underground linkway was constructed beneath a live 9-lane carriageway and above two operational MRT tunnels, all of which remained fully functional throughout the construction process. Due to the presence of the carriageway which could not be diverted, a trenchless construction method known as the pipe roof method was adopted instead of the conventional cut-and-cover technique. The method employed a three-sided pipe roof along with ground improvement at the base of the excavation rather than the typical full enclosure pipe box system. This paper outlines the key design considerations and construction challenges encountered. It also discusses the observed performance of the mined excavation and compares it with predictions from a two-dimensional finite element analysis (FEA). The successful application of this design methodology provides a valuable reference for similar underground linkway construction in dense urban environments.

In early 1996, the Singapore Government announced its decision to expand the country's mass rapid transit (MRT) system by building the North-East Line from the World Trade Centre in the south of the island to the new towns of Hougang, Sengkang and Punggol in the north-eastern part of Singapore. The 2.55bn North-East Line is approximately 20 km long and is built primarily underground using precast tunnel-lining segments. Contract C708 of this project included a stretch of bored tunnel passing through bacterially active marine clays and underneath the Singapore River, possibly the worst soil and groundwater conditions to be found in Singapore. The specification requirements for the project referred to a 100-year design life and included the use of high-performance concrete with a maximum water-cementitious material ratio of 0.45 and a minimum 28-day compressive strength of 60 MPa for the concrete used in the precast tunnel segments. In addition, the specification included the use of high yield bars with a fused epoxy coating to mitigate corrosion of the reinforcing steel due to chlorides in the groundwater. At the request of the contractor, the specifying agency accepted the use of a dense silica-fume concrete and integral waterproofing corrosion inhibitor as an alternative to the epoxy-coated bar. Over 8,000 precast, high-performance concrete tunnel-lining segments were produced for the construction of the underground tunnels, which were completed in December 2000. This paper summarises the development of the high-performance concrete mixes for the tunnel lining segments, production issues and QA/QC measures that were implemented to ensure compliance with the specification. For the covering abstract see ITRD E116313.

Mass rapid transit systems around the world are typically designed for all-stop operation schemes, in which train overtaking is not possible. To accelerate transit operation, the conventional A/B skip-stop scheme may be planned. This research explores alternative skip-stop schemes with three stop patterns, aiming to better match transit services with the spatial distribution of travel demand. The proposed generalised skip-stop operation model considers both the total cost of passengers and operator. A genetic algorithm is employed to solve the stop-plan optimisation problem, and a heuristic is tailored to determine an optimal dispatch headway for the respective stop plan. Based on computational experiments using synthetic data, the results suggest that skip-stop schemes have the potential to reduce total time costs by about 10%, particularly when there are structured demand concentrations, transit systems can operate safely with low time headway and short-distance demand is low. Although the total-cost saving of the best A/B skip-stop plan found is generally superior to those of other three-pattern skip-stop schemes, a three-pattern skip-stop scheme was found to offer a better total-cost saving in a scenario without short-distance travel demands. Overall, this research offers valuable insights into the potential benefits and limitations of different skip-stop schemes, contributing to a better understanding of their impact on passengers and operators.

This paper generally describes the various touch voltage protection measures adopted mass rapid transit (MRT) systems. Particular reference is drawn from the practices adopted in the Singapore MRT system. There are potential hazards of electric shocks to passengers and working staff touching conductive surfaces of different voltage potentials e.g. around the platform edge particularly between the platform screen doors and train or train depot workshop area. As such, there is a need to address this concern through the application of appropriate touch voltage protection. It is recognised that prior to examining the earth (grounding) details, an important but often obscure concept of touch voltage protection must be fully understood and considered to ensure that the touch voltage protection have been properly catered for to mitigate the potential hazard. This paper also outlined the touch voltage protection methods adopted in the existing Singapore MRT depot areas. Problems experienced on touch voltage protection issues in existing Singapore MRT system are also highlighted. Provisions of touch voltage protection devices i.e. running rails to earth voltage limiting device (64P relay) and fault voltage monitoring equipment (FVME) are also discussed in the paper. Various civil provisions for touch voltage protection issues at stations especially at those stations with platform edge columns are also covered. In addition, the paper also outlines the adopted integrity measurements for installations within the protection zone for the required touch voltage protection purposes.

The effect of proximity to a transit system on property values has become a key issue of debate regarding public infrastructure and economic development. This article aims to examine the impact of selected stations along the Blue line of Delhi Mass Rapid Transit System (MRTS) on commercial property prices. The research analyzed 1,413 commercial property parcels sold before and after the commissioning of Blue line in 2005. Hedonic Price Analysis (HPA) was used to estimate the effects of proximity to the metro rail on commercial property values. The method was applied to two time periods, i.e., from 2000-2004 and 2005-2008, coinciding with planning and construction (pre-commissioning phase and the operation phase (post-commissioning phase) of metro rail using actual sale prices of commercial units. The results indicate that a station node shows a negative trend during the planning and construction period. However, the operation period has produced a significant price premium associated with commercial properties, connected with improved accessibility. The coefficients indicate that MRTS has induced an increase in prices from INR 732.80 to INR 246.19, and its radius of impact covers an area of approximately 1/2 km from the stations. The methodology and results provide insight with a specific focus on commercial real estate values in other metropolitan cities developing and expanding MRTSs.