In traditional metro weak current systems, subsystems built by different manufacturers are physically separated, and devices are redundant while data are isolated. This causes low resource use, high maintenance cost, long customization cycles, and high interface complexity. In this paper, based on an analysis of the problems in traditional metro weak current systems, a novel cloud and microservice-based urban rail transit integrated supervisory control system (ISCS) named ISCS Plus is proposed. The integration mode of each subsystem is determined by analyzing safety requirements, real-time performance, and business characteristics. An infrastructure platform is designed to share resources and isolate applications based on cloud computing technology, while traditional subsystems are decomposed as microservices and merged into different applications. Finally, the entire architecture of ISCS Plus is established and its features are discussed. ISCS Plus plays a key role in the systematic, intelligent, and automatic solution for metro weak current systems and supports the development of the world's leading metro weak current systems.
Rail transit systems are one of the most important and popular types of transit systems used daily in metropolitan areas all around the world. The third rail is one of the providers of traction power in electrified rail systems, but it faces several issues, such as insulator failures. The purpose of this study is to investigate the causes of insulator failures, which have not been comprehensively studied and presented in the literature. To accomplish this objective, eight transit systems with third rails were selected to (1) investigate the characteristics of third-rail systems, (2) determine the causes of insulator failures, (3) analyze the costs associated with insulator failures, and (4) determine mitigating practices to reduce the number and cost of insulator failures. After a thorough literature review, details of eight case studies were collected from different transit agencies, and their subject matter experts were asked to complete a survey and provide input. The results revealed that a build-up of dirt was the major cause of the 17 identified causes of insulator failures; carbon dust and dirt were identified as the most present particles in third-rail systems. It was noted that transit agencies often implement multiple mitigating practices such as cleaning the insulator, performing visual inspections, and conducting regular maintenance to reduce the number and cost of insulator failures. The findings of this study will help decision-makers for transit systems make timely decisions to prevent third-rail insulator failures and adopt appropriate practices that best fit their transit system.
The rail vehicle door system is one of the key components of rail vehicles. Its failure rate accounts for more than 30% of vehicle failures. By analyzing early warnings provided by subhealth data from the door system, the efficiency and reliability of their health maintenance can be effectively improved and stable operation of the door system can also be guaranteed. In this paper, early-stage resistance changes in the subhealth state of rail vehicle door systems are considered as the research object. Firstly, the distribution rules for the motor parameters are studied, and the time-domain and normal operating envelope features of the operating motor are extracted. Secondly, subhealth conditions with different resistances are simulated using a test rig, and the experimental data are applied to summarize the rules. According to the subhealth types and the distribution of features, diagnostic rules for subhealth are formulated. To check the possibility of fault diagnosis, a verification using running rail vehicle door system data is carried out in MATLAB. The results reveal that the misdiagnosis rate of resistance subhealth is 0% while the rate of missed diagnoses is 2%. Meanwhile, the diagnostic process based on the established rules is relatively efficient. This method is suitable for application for resistance subhealth diagnosis of urban rail vehicle door systems.
Understanding the service quality of public transportation based on users’ perception is an important input for local governments and transit service providers in their planning efforts to improve system performance. Using the Addis Ababa Light Rail Transit (AALRT) as a case, this study aims to examine service users' views and perspectives by using 18 quality attributes. Factor analysis and ordered logit model were employed for this study. Factor analysis with principal components was used to extract the most important factors of satisfaction from the 18 attributes. The results showed that safety and security, ticketing system, travel information, crowdedness, frequency, cleanliness, and comfort are the most important factors influencing user satisfaction. The level of importance of these factors varies depending on different socioeconomic and travel characteristics of AALRT users. Riders who use the light rail at afternoon peak hours, have high household income and short travel duration, and use LRT for shopping purposes have a negative perception regarding the crowdedness, frequency, ticketing, and information system of the AALRT. Passengers with longer travel distance, those who use the AALRT frequently, and full- or part-time workers and students have a positive perception towards several attributes of the system.
The aim of this study is to investigate the effects of traffic loads and track parameters, including track curvature, superelevation, and train speed, on vertical and lateral rail wear. The Yenikapi–Ataturk Airport Light Rail Transit (LRT) line in Istanbul was selected as a case study, and rail wear measurements were carried out accordingly. Passenger counts were performed in all wagons of the train on different days and time intervals to calculate the number of passengers carried in track sections between stations regarding traffic loads on the LRT line. Values of traffic load, track curvature, superelevation, and speed were determined for each kilometer where measurements of rail wear were conducted. A multiple linear regression analysis (MLRA) method was used to identify effective parameters on rail wear. Independent variables in MLRA for both vertical and lateral wear include traffic load, track curvature, superelevation, and train speed. The dependent variables in MLRA for vertical and lateral wear are the amount of vertical and lateral wear, respectively. The correlation matrix of the dependent and independent variables was analyzed before performing MLRA. Multicollinearity tests and cross-validation analyses were conducted. According to the results of MLRA for vertical and lateral wear, the obtained coefficients of determination indicate that a high proportion of variance in the dependent variables can be explained by the independent variables. Traffic load has a statistically significant effect on the amount of vertical and lateral rail wear. However, track curvature, superelevation, and train speed do not have a statistically significant effect on the amount of vertical or lateral rail wear.
Passenger ropeways are a promising alternative for the development of public transport infrastructure in large cities. However, the construction of ropeways has a rather high cost and requires taking into account a significant number of restrictions associated with the features of the existing urban development and the placement of urban infrastructure. The main objective of this research is to develop optimization models that minimize the total cost of modular intermediate towers of a discretely variable height and a rope system due to the optimal placement and selection of the height of these towers, taking into account the features of the surface topography and urban development. The proposed modular principle for the construction of intermediate towers also enables the cost of construction to be further reduced. As a specific example, the design of a ropeway in the city of Bryansk, which has a complex terrain, is considered. The developed models are conveniently used at the initial stage of the design of the ropeway to compare the cost of various options for the location of the ropeway route in order to reduce the risk of error when choosing the least expensive option. The calculation results can serve as a guide for a preliminary assessment of the number and height of intermediate towers, their installation locations on the ground and the characteristics of the cable system.