Urban rail transit connecting with a comprehensive transportation hub should meet passenger demands not only within the urban area, but also from outer areas through high-speed railways or planes, which leads to different characteristics of passenger demands. This paper discusses two strategies to deal with these complex passenger demands from two aspects: transit train formation and real-time holding control. First, we establish a model to optimize the multi-marshalling problem by minimizing the trains’ vacant capacities to cope with the fluctuation of demand in different periods. Then, we establish another model to control the multi-marshalling trains in real time to minimize the passengers’ total waiting time. A genetic algorithm (GA) is designed to solve the integrated two-step model of optimizing the number, timetable and real-time holding control of the multi-marshalling trains. The numerical results show that the combined two-step model of multi-marshalling operation and holding control at stations can better deal with the demand fluctuation of urban rail transit connecting with the comprehensive transportation hub. This method can efficiently reduce the number of passengers detained at the hub station as well as the waiting time without increasing the passengers’ on-train time even with highly fluctuating passenger flow.

Fire is one of the most common disasters that threaten the safety of the crowd in metro stations. Due to the variations in the design of metro stations, the hazard posed by the spreading products of the fire can pose different risks. The typical structures of metro stations in Guangzhou and Washington, D.C., are very different from each other. In Washington, D.C., the “high-dome” structure is predominant in the construction of metro stations, while in Guangzhou, most metro stations have the “flat ceiling” structure. In this article, a numerical modeling for fire dynamic simulation is used to predict and compare the spreading characters of fire products (the smoke height change, the temperature distribution and the visibility change) when fires with 2.5 MW heat release rate occur in the platform center and at the platform end in the two kinds of metro stations. The results show that, in the same fire scenario, the lowest smoke heights monitored in the Guangzhou model is 0.6 m (fire at the platform end) and 0.8 m (fire in the platform center) above the safe smoke height in 360 s after a fire breaks out, while it is 6.15 m (fire in the platform center) and 6.2 m (fire at the platform end) above the smoke height in the Washington model. The temperature increment in the Guangzhou model is 23 °C (fire in the platform center) to 29 °C (fire at the platform end) in 360 s after the fire breaks out, while the temperature increment in the same period in the Washington model is 8.5 °C (fire at the platform end) to 9 °C (fire in the platform center). The visibility of most areas on the platform of the Guangzhou model is about 1 m no matter the fire is in the platform center or at the platform end at 360 s after the fire begins, while in the Washington model, the visibility of most areas is 1.5–13.5 mm (fire at the platform end) to 4–14 m (fire in the platform center) at the same moment. Based on the results, the environment is worse when the fire happens at the end of the platform than that when the fire happens in the platform center of the Guangzhou model. While the fire location has fewer impacts on the smoke height, temperature, and visibility in the Washington model, metro stations with a high-dome structure can be beneficial to fire evacuation safety; however, the construction cost can be high. Metro stations with flat ceiling are widely used in more cities for it has lower construction cost; to compensate for its weaker abilities under fire conditions, it is suggested that smoke exhaust systems should be carefully and fully considered.

Track–vehicle severe interaction on track with small curve radius results in rail wear and corrugation, and wheel polygonization, which drain considerable resources for rail grinding and wheels re-profiling in metro lines. To reduce the damage caused by track-vehicle severe interaction, the paper analyzes the reasons leading to rail wear and then proposes an architecture of a metro vehicle with independently rotating wheels driven directly by permanent magnet synchronous motors. The architecture is axle guidance, offered by passive linkages, which ensures that all axles are oriented radially, while control strategy was kept as simple as possible, identifying only two basic traction conditions. The concept is first discussed and then validated through a comprehensive set of running dynamics simulation performed with a multibody software to evaluate rail wear and rolling contact fatigue in traction/braking, coasting with different cant deficiency/excess conditions. The multibody dynamics simulation shows that the proposed architecture is virtually capable of avoiding both wear and rolling contact fatigue damages, and achieves the highest possible track friendliness. The concept of the proposed architecture is a track-fiendly metro architecture and could be a good reference for reducing rail-track interaction damages and maintainace cost.

With the accelerated urbanization in China, along with the growing scale of the metro transportation network, the energy consumption of metro systems continues to increase. To face the tough challenge of climate change, China has put forward the goal of peak carbon emissions by 2030 and achieving carbon neutrality by 2060. Energy consumption has become a serious burden for metro operation companies, since 10.2% of the total operational budgets is spent on electricity. Thus the development of methods to realize energy saving and emission reduction has become a major challenge for metros. In this study we conduct an in-depth research and analysis on metro energy load classification and energy management, focusing in particular on the design and usage of power supply systems for metro weak current electromechanical systems, including tunnel fans, station air conditioners, station escalators, automatic ticketing equipment, screen doors, drainage pumps, sewage pumps, platform doors, communication systems, signals, integrated monitoring systems, automatic ticketing and various lighting equipment and facilities. It is proposed that the five weak current systems, namely platform doors, communication systems, signals, integrated monitoring and automatic fare collection, should adopt a backup power supply. In order to ensure the reliable operation of all weak current systems in the station, the traditional decentralized power supply mode is changed to a centralized power supply and uninterruptible power supply (UPS) (1 + 1) parallel double-bus system. At the same time, combined with the data on equipment quantity, station passenger flow and station building floorage, the Boruta algorithm is used to filter out the equipment related to station weak current energy consumption, and a principal component analysis (PCA) algorithm is used to further reduce the dimensions of the filtered features to reduce the algorithm overhead of the subsequent quota analysis model. The XGBoost algorithm is used to establish a prediction model for station weak current system energy consumption. Analysis shows that there is a strong correlation between the energy consumption quota and the equipment quantity as well as station building floorage. By setting different metering instruments for power supply circuits, the main energy consumption data are collected to meet the requirements for graded metering of metro energy consumption, and then the energy consumption quota for the station weak current system is reasonably predicted. By adding metering instruments to the power supply circuits of different areas and equipment, the energy consumption of the weak current system can be measured and monitored in different grades. The combination of the energy management platform and energy consumption quota provides the basis for energy management of each energy-consuming unit, and ultimately realizes energy saving and reduced consumption.