Abstract: Research Objective: To establish a comprehensive monitoring system with appropriate scale, scope, depth, and function, and to leverage its comprehensive coordination role in subway operation, is a primary issue in the design of such a system. Therefore, it is essential to first conduct research on the operation mode of the rail transit comprehensive monitoring system. Research Results: Through comparison of multiple schemes regarding system integration scope and depth, a suitable integration scheme was proposed. For different operating conditions in subway operation, such as normal operation, congestion, faults, maintenance, platform fires, concourse fires, and section fires, schemes on how to coordinate the operation of each subsystem were proposed. 1 Overview of the Comprehensive Monitoring System In urban rail transit operation, various electromechanical systems are set up to ensure the normal operation of the rail transit system and the safety of passengers and staff. Although their functions and responsibilities differ, they are intricately connected. Changes in one system often require adjustments to other systems, especially in situations such as train section congestion or fires, where multiple systems need to work together. To improve the level of automated operation management in rail transit, some domestic rail transit lines are already considering and experimenting with comprehensive automated control and management of rail transit operations. After adopting the integrated monitoring system, the system integration and interconnection of related functions of the station and control center were realized, improving the technical level of the equipment; the sharing of data information can improve the utilization rate of data and realize the organic linkage between systems under different operating conditions, improving the automation and scientific level of management. The flexible setting of the operation terminal provides conditions for optimizing the operation management system in the future, improving the efficiency of rail transit operation and reducing operating costs. 2 Overall Composition of Integrated Monitoring System 2.1 Integration Method of Integrated Monitoring System Due to the different integration scope and integration depth, the integrated monitoring system can be divided into the following methods. 2.1.1 Classification by Integration Scope The integrated monitoring system can be divided into three methods according to the integration scope: full integration, quasi-integration, and partial integration: 2.1.1.1 Full Integration: Based on the ATC system and core, communication, signaling, control system and all weak current monitoring systems are integrated into one system, which is an ideal integration scheme. However, it involves too wide a scope and the technology is very complex, and it is currently too difficult to implement. 2.1.1.2 Quasi-integration: In addition to the main communication system, the ATC system (related to train safety), and the AFC system (related to financial security), multiple monitoring systems are integrated into one system. This significantly improves the current fragmented and disorganized situation of separate systems and facilitates the implementation of system linkage functions, greatly enhancing the automation level of rail transit system operation and scheduling. 2.1.1.3 Partial integration: This integrates some single-function monitoring systems (such as FAS, BAS, SCADA, etc.) into one system. The advantage is ease of implementation, but the disadvantage is that it does not significantly improve the overall operation and maintenance effect of the rail transit system. 2.1.2 Classification by Integration Depth: From the perspective of integration depth, integrated monitoring systems can be classified into three integration depth schemes: field-level integration - full integration (deep integration), execution-level integration - quasi-integration, and management-level integration - surface integration (top-level integration). 2.1.2.1 Top-level integration: Subsystems are integrated at the monitoring layer of OCC and stations. The integrated monitoring system collects and processes data from various subsystems at the management level, realizing information sharing, interaction, and system linkage functions between subsystems. The advantage of this approach is its simplicity, but it still suffers from drawbacks such as a large variety of station-level equipment and interfaces, and difficulties in implementing联动 (interconnection/linkage). This approach has the lowest integration level. 2.1.2.2 Quasi-integration: The communication protocols between the field acquisition, drive equipment, and execution layer are all internal system protocols. The two layers of equipment are inseparable, and integrated monitoring systems generally do not choose to integrate at this level. 2.1.2.3 Field-level integration (deep integration): The integrated subsystems are completely integrated using the same software platform. The central layer, station monitoring layer, and control layer of the integrated subsystems are integrated onto the integrated monitoring platform, and their functions are all implemented by the integrated monitoring software. The system application software is completely unified, data processing is simple and rapid, and the inter-system联动 (interconnection/linkage) functions are diverse, secure, and simple. The coordination between the integrated monitoring system and each subsystem is handled by the integrated monitoring system integrator, reducing the project management workload for the construction party. Deeply integrated monitoring systems are a type of system independently innovated in my country's subway engineering practice. It overcomes the shortcomings of top-level integration by using a single software platform to fully integrate the subsystems into the comprehensive monitoring system. The software platform can be extended to the field level, enabling real-time control and remote operation, resulting in good system effectiveness and responsiveness. 2.2 Scope of Integration into the Comprehensive Monitoring System From the perspective of the current state of comprehensive monitoring system construction, certain specialties (such as signaling and automatic fare collection (AFC)) are not yet suitable for inclusion in the comprehensive monitoring system. The subway signaling system is the main specialty of the subway. Currently, the system technology used in my country's subway signaling specialty is mainly imported from abroad, forming a self-contained system with incomplete open communication protocols and strictly confidential software. Furthermore, the signaling system must ensure train operation safety; analyzed from the perspective of computer control systems, it is a safety system. Therefore, it must operate independently and is not allowed to be excessively interfered with by other systems, nor can it be connected to non-safety systems that could affect operational safety. Therefore, the subway signaling system should ideally operate independently, only interconnecting with the subway information platform to exchange relevant information. The subway automatic fare collection (AFC) system involves ticketing management and financial management. Both ticketing and financial data require secure and relatively independent collection and transmission to improve security. Therefore, the AFC system has certain limitations in information exchange and resource sharing with other systems. Thus, limited information interconnection and data sharing are only suitable for the AFC system. The subway fire alarm (FAS) system is a system with strict industry management, requiring construction entirely according to local fire department requirements. From the current technical level, it is entirely possible to integrate it into the integrated monitoring system, but it must be designed according to local environmental conditions. If integration is not permitted, it should be designed according to interconnection methods. 3. Functions of the Integrated Monitoring System 3.1 System Functions under Normal Operating Conditions Under normal conditions, the central dispatcher will be responsible for the scheduling and management of the integrated monitoring system and its subsystems, coordinating the work between relevant business stations, sharing the operational information of each subsystem on the network, coordinating the cooperation between relevant dispatching stations, and monitoring the relevant operating status of each system's equipment. In the daily monitoring and management mode, the OCC monitors all stations and relevant professional systems along the entire line. It starts and stops various equipment according to pre-arranged sequences and prescribed modes, and can adjust system parameters such as power supply, lighting, environmental control, guidance display, and ticketing based on train operation information, passenger flow information, and environmental detection parameters, monitoring the working status of each system. 3.2 Interlocking Control Function in Fire Mode When a fire occurs, relevant emergency response measures are formulated based on the actual situation on site, timely decisions are made, and the disaster prevention command center is supervised to complete various procedures and effectively command the operation. Once the on-site detection equipment at the station and control center confirms the fire alarm information, the OCC automatically switches to the disaster prevention command center and automatically switches to the system-wide disaster mode. At this time, the integrated monitoring system integrates on-site alarm information, train location, and other relevant information to coordinate the work of various related systems. The environmental control workstation at the control center automatically becomes the disaster prevention command center station, displaying the main disaster prevention command screen; the large screen system can divide the screen according to the fire mode, becoming the display window of the command center system, and sending fire alarm information to the dispatch center. Each station's environmental control system, smoke extraction system, fire pump station, platform screen doors, power lighting system, access control system, broadcasting system, passenger information system, CCTV system, automatic fare collection system, etc., automatically enters fire mode and simultaneously and automatically enters the corresponding working state according to the predetermined method. 3.3 Centralized Interlocking Function in Congestion Mode: When congestion occurs, the system formulates relevant emergency response measures based on the actual situation on site, coordinates the work between various operational stations with the OCC command center personnel, and makes timely decisions and provides effective command. When a train is obstructed at a platform or in a tunnel, the metro operation is disrupted. After receiving information from the ATS, the integrated monitoring system automatically enters congestion mode. The OCC large screen displays a message indicating the entry into congestion mode, and the alarm system alerts operators in the OCC and station control rooms to enter congestion mode. The system also displays the train's location, status, and direction of travel on the OCC large screen and the duty officer's workstation in the control room. All relevant systems will also coordinate and interact to assist OCC dispatchers in clearing the congestion. 3.4 Centralized Interlocking Function in Fault Mode: When a major system equipment malfunctions, affecting the safe operation of the metro system or endangering equipment or personal safety, the integrated monitoring system automatically enters fault mode. The OCC large screen displays a message indicating the entry into fault mode, and the alarm system alerts operators in the OCC and station control rooms to enter fault mode. All relevant systems will also coordinate and interact. 3.5 Centralized Maintenance Mode Under normal circumstances, the maintenance dispatcher is responsible for monitoring the operational technical status of relevant equipment within the scope of each business station's monitoring, establishing equipment ledgers, organizing and formulating comprehensive maintenance plans and measures, providing equipment maintenance plans to relevant business stations, and performing maintenance management work. It also organizes and directs regular or temporary on-site equipment maintenance work. After train operation ends, if maintenance of important systems such as tunnel structures, tracks, and overhead contact lines is required, the integrated monitoring system enters maintenance mode, and all relevant systems will coordinate and interact. 3.6 Maintenance Dispatch Function in Abnormal Situations When a fire or blockage occurs, it cooperates with the disaster command center to participate in disaster and accident rescue work, understands the operational status of on-site equipment, grasps the post-disaster equipment operation situation, and formulates maintenance plans and measures based on the actual situation. 4 Integrated Monitoring System Coordination Modes under Various Operating Conditions 4.1 System Operating Mode under Normal Circumstances Under normal circumstances, the integrated monitoring system enters normal operating mode, which is the daily monitoring and management mode of the integrated monitoring system. The OCC monitors all stations and professional systems along the entire line. The station's integrated monitoring room monitors all professional systems within the station. 4.2 Interaction between Systems During a Fire When the on-site detection equipment at the station and control center confirms the fire alarm information, the OCC automatically switches to the disaster prevention command center and automatically switches to the disaster mode of the entire system. At this time, the integrated monitoring system will integrate on-site alarm information, train location and other relevant information to coordinate the work of various related systems. The control center's environmental control workstation automatically becomes the disaster prevention command center station and launches the main disaster prevention command screen; the large screen system can divide the screen according to the fire mode to become the display window of the command center system. When the FAS confirms the fire alarm information, the integrated monitoring system automatically starts the disaster mode of the entire system. At this time, the integrated monitoring system will integrate FAS alarm information, CCTV real-time images, the operation status of trains on the entire line and other information to monitor the coordinated work of various professional systems. The entire subway operation automatically responds quickly to the fire and automatically enters an orderly and coordinated disaster prevention work mode. The entire disaster prevention process can be displayed in an orderly and hierarchical manner on the OCC large screen. 4.2.1 Fire Occurs in the Station Area When a fire occurs in the station hall or platform, the BAS system will receive the fire alarm signal from the FAS and the corresponding mode. (1) The station’s integrated control room automatically becomes the disaster prevention command center and notifies the control center to coordinate and dispatch the operation of all trains on the line. (2) The FAS monitoring station automatically becomes the disaster prevention command workstation and pops up the main disaster prevention command screen. (3) The BAS operates according to the fire mode control command, the station tunnel fans and platform fans operate according to the station monitoring main station mode command, and the elevators and escalators enter the disaster prevention position. (4) The power SCADA system cuts off the non-fire power supply of the station and starts the emergency lighting. (5) The power supply of the station ticket machine gates is cut off because it is not for fire protection, and the ticket sales and inspection work stops. (6) The controlled doors of the access control system will be automatically unlocked. (7) According to the passenger evacuation direction, some platform screen doors open to assist passengers in evacuation, while others close to prevent smoke from entering the platform. (8) All trains on the line operate in a disaster prevention manner according to the fire location information (dispatched by the control center). (9) The CCTV automatically controls the relevant cameras to aim at the accident site and passenger evacuation channels, and pops up the video real-time monitoring screen on the large screen of the disaster prevention command center (OCC). (10) The broadcasting system automatically selects zones to broadcast messages under fire mode, including the location of the fire, the fire situation, the direction of passenger evacuation, the position and direction of train operation, etc.; (11) The passenger guidance system and the station information system broadcast various passenger guidance command information from the disaster prevention center, and the station plasma screen mainly plays real-time information related to the disaster and disaster prevention command information. (12) The control center large screen system can divide the screen according to the disaster mode and become the display window of the disaster prevention command system. 4.2.2 When a fire occurs in the tunnel area, the alarm information is formed by the train position signal provided by the OCC environmental control integrated monitoring system and the train driver's verbal report of the fire information at the front and rear of the train. The corresponding mode is also determined by human judgment. The corresponding mode is manually triggered by the OCC environmental control, or the OCC environmental control notifies the corresponding station operator. (1) The control center automatically becomes the disaster prevention command center, directing the two connected stations in the fire area, and the control center coordinates and dispatches the operation of all trains on the line; (2) The FAS monitoring station automatically becomes the disaster prevention command workstation and launches the main screen of disaster prevention command; (3) The environmental control ventilation system of the two connected stations in the fire area operates according to the fire mode control command, and the station tunnel fans and platform fans operate according to the station monitoring main station mode command; (4) The power SCADA system cuts off the non-fire-fighting power supply of the two connected stations in the fire area and starts the emergency lighting; (5) The elevators and escalators of the BAS system of the two connected stations in the fire area enter the disaster prevention position; (6) The power supply of the ticket vending and inspection machine gates of the two connected stations in the fire area is cut off because it is non-fire-fighting, and the ticket vending and inspection work stops; (7) The controlled doors of the access control system of the two connected stations in the fire area will be automatically unlocked; (8) Passengers are allowed to evacuate in the direction of fresh air evacuation; (9) All trains on the line operate in a disaster prevention manner according to the fire location information; (10) CCTV automatically controls relevant cameras to point at the accident site and passenger evacuation routes, displaying real-time video monitoring images on the large screen of the disaster prevention command center. 4.3 Interaction of Systems During Blockage When a train is blocked at a platform or in a tunnel, the subway operation is disrupted. After receiving confirmation from the ATS, the integrated monitoring system automatically enters the blockage mode. The OCC large screen sends a message indicating that the system has entered the blockage mode. The alarm system reminds operators in the OCC and the control rooms of each station to enter the blockage mode, and displays the train's location, status, and direction of travel on the OCC large screen and the duty officer's workstation display in the control room. All relevant systems will also coordinate and interact to assist the OCC dispatchers in eliminating the blockage. (1) The BAS controls the fans and air conditioners according to the mode control instructions of the OCC, and increases the ventilation and cooling capacity of the platform. (2) The elevators and escalators of the station equipment operate under the blockage condition and are under the command of the integrated monitoring system. The platform screen doors open automatically to evacuate passengers. (3) The CCTV cameras are aimed at the blockage site and the passenger evacuation passage and displayed on the station video display and the OCC large screen for use by the command personnel. (4) The broadcasting system broadcasts according to the blockage mode (the broadcasting and the content of the broadcast are determined according to the actual situation). (5) The passenger guidance and station information system guides the evacuation of passengers on the terminal display screen and reflects the operation status of the train. (6) The position, status and direction of the train are displayed on the monitoring screen of the OCC and the station integrated monitoring room to assist the OCC commander in eliminating the blockage. 5 Conclusion (1) Through comparison of multiple schemes, the scheme of deep integration of the integrated monitoring system without integration of signal, AFC and interconnection of FAS system is more suitable. (2) Under different operating conditions such as normal operation, congestion, malfunction, maintenance, platform fire, station hall fire, and section fire during subway operation, each electronic system should operate in coordination according to the plan predetermined by the integrated monitoring system in order to give full play to the role of the integrated monitoring system and effectively improve the level of automated management of urban rail transit operation.