Abstract: This paper introduces the development history of the Automatic Fare Collection (AFC) system in China's urban rail transit, pointing out that "one-card-for-all" is the development direction of the AFC system. The application of IC card technology has enabled the subway fare collection system to share a single card with other public transportation fare collection systems. To ensure the steady development of the AFC system, key points and corresponding measures to be grasped to guarantee the smooth implementation and efficient operation of the system are proposed. Keywords: Urban rail transit automatic fare collection system, IC card. In the subway system, the automatic fare collection system (AFC system), with its highly intelligent design, plays the roles of ticket seller, ticket inspector, accountant, statistician, and auditor, realizing a high degree of automation in ticket management through data collection and control systems. With the rapid development of electronic technology, the concept and technology of automatic fare collection systems have also undergone tremendous changes, and the application of convenient means such as one-card-for-all and e-wallets is becoming increasingly popular. Faced with this ever-expanding social demand, it is necessary to review the development history of China's urban rail transit AFC industry, effectively solve the problems that must be considered in the current and future development of the AFC industry, and ensure the orderly and healthy development of the system. 1. The Development History of AFC in China's Urban Rail Transit Over the past decade, China's AFC (Automatic Fare Collection) system for urban rail transit has grown from nothing to something, experiencing three stages: enlightenment, practice, and adjustment. 1.1 Enlightenment Stage In the late 1980s, Shanghai Metro, relying on data collected abroad, painstakingly began developing its AFC system and equipment. At that time, the concept of an AFC system for urban rail transit was still a blank slate in China. In the feasibility study report for Guangzhou Metro Line 1 in the early 1990s, whether the fare collection method would be manual or automatic was still an important chapter. During this stage, the functional design of the AFC system was mainly based on learning from successful foreign systems. During this period, Hong Kong MTR shared its valuable construction and operation experience with the mainland; at the same time, internationally renowned professional manufacturers also introduced many of their good technologies and experiences in urban rail transit AFC systems to China through product and system introductions. All of this laid the foundation for the Guangzhou Metro and Shanghai Metro AFC systems to have basically complete functions from the beginning of their construction. The first AFC system supply contract for urban rail transit in China was signed in the mid-1990s. At that time, international magnetic card AFC system technology was quite mature, while research on the application of IC card technology in transportation fare collection had just begun. The Paris Metro and Hong Kong Metro were considering applying contactless IC cards to rail transit and bus fare collection, while research on the application of IC cards in public transportation in my country was still at the level of contact IC cards. Due to the very high cost of IC cards at the time, magnetic cards were preferred over other media such as magnetic cards, IC cards, and barcodes. 1.2 Implementation Phase Starting at the end of 1998, the AFC system was put into use in urban rail transit in mainland China, gradually demonstrating its excellent ticketing management level and efficient passenger flow handling capabilities. This enabled metro companies to manage ticketing revenue with minimal manpower and resources, achieving high efficiency and low cost. The system's effectiveness was accepted by designers, builders, and passengers. During this phase, domestic rail transit AFC system users, through use and exploration, mastered the rich and diverse, scientifically rigorous functions of the original system while summarizing and refining many new functions suitable for rail transit ticketing management, further improving the functionality of the AFC system. After several years of practice, the superiority of the rail transit AFC system can be seen from the following aspects. (1) Accurate passenger flow and ticketing statistics and analysis data: provide scientific decision-making basis for operation control, marketing and new line construction, and also create conditions for improving service quality and information processing capabilities. (2) Efficient AFC equipment: enables orderly and rapid passenger flow in stations, reduces intentional and unintentional fare evasion, and ensures the ticket revenue of the subway company. (3) Automatic fare collection system: can greatly reduce cash transactions, manual accounting and statistical work, streamline personnel, and has high accuracy and efficiency. (4) Maintenance management system: enables better utilization of maintenance resources and achieves the effect of fast response and fast repair. 1.3 Adjustment stage In just a few years, the application of IC card technology in rail transit AFC system has rapidly developed from research and exploration to large-scale practical application. With its large storage capacity, strong confidentiality and the ability to realize multiple uses of one card, contactless IC card has gradually replaced the magnetic card and has now become the preferred ticket medium for urban rail transit fare collection systems. The large-scale application of contactless IC card technology in rail transit AFC systems has significantly impacted existing AFC systems that use magnetic cards as the ticket medium. Simultaneously, it has driven the functional expansion and performance improvement of AFC systems on newly built lines, resulting in simpler, more efficient systems with reduced costs. Guangzhou and Shanghai, while constructing new lines, have prioritized adjustments to their existing systems, placing the transformation of their original magnetic card AFC systems on their important agendas. During the adjustment phase, they faced a choice similar to many major international cities: one was to immediately switch to a full IC card system, using IC cards for all ticket types; the other was to first convert stored-value tickets to IC cards, while retaining the existing magnetic cards for single-journey tickets, and then switch to a full IC card system when the time was right. In considering the transformation plan, we believe that one of the biggest differences between rail transit in my country and in major international cities is that my country's rail network is still in its early stages of construction, while some major international cities have already built relatively stable networks spanning hundreds of kilometers. In major international metropolitan areas, it's perfectly feasible to switch from stored-value tickets to IC cards while retaining magnetic cards for single-journey tickets. However, my country's urban rail transit network is still in its early stages of construction, making the adoption of a full IC card system for new lines imperative. If existing lines continue to use magnetic card single-journey tickets or only partially add IC card single-journey tickets, magnetic card single-journey tickets will not be accepted on new lines, or the system will become complex due to the coexistence of two types of single-journey tickets, causing passenger confusion. Therefore, the simpler the existing network, the more advantageous it is to upgrade to a full IC card system. After analyzing and comparing domestic and international situations, Guangzhou Metro made a decisive decision: while constructing the AFC system on Guangzhou Metro Line 2, it upgraded the original magnetic card fare collection system on Line 1 to a full IC card system, providing a unified technical standard for the AFC systems of new lines. Currently, Guangzhou Metro's full IC card AFC system is in operation, and Shanghai Metro has also completed its upgrade and implemented IC card stored-value tickets, and will soon launch IC card single-journey tickets. 1.4 Current Status Currently, all newly built rail transit AFC systems nationwide utilize contactless IC card technology, which boasts high information processing capabilities and enhanced security. The system equipment is simplified, significantly reducing ticket-related issues and consequently decreasing the workload of mechanical maintenance and adjustments. Simultaneously, it provides greater convenience for passengers, allowing them to pass through ticket checks without needing to retrieve their tickets from their bags. The application of IC card technology has made joint operations in the public transportation industry a development trend, bringing greater convenience to passengers. Currently, Shanghai's "One Card" and Guangzhou's "Yangcheng Tong" systems have expanded to the transportation sectors of multiple cities. For example, Shanghai uses a unified card for buses, subways, taxis, ferries, parking lots, and light rail transit; Beijing and Dalian have also implemented unified cards for buses and light rail transit. 2. Key AFC System Development The AFC initiative aligns with the development direction of urban informatization, allowing people to enjoy public transportation, municipal services, financial services, medical services, shopping, and landscaping services with a single card. However, we must also recognize that for cities like Shanghai, Guangzhou, and Beijing, which are expanding their networks, or Shenzhen, Hangzhou, and Nanjing, which are just starting to build their networks, as well as cities planning AFC (Automatic Fare Collection) projects, the following seven aspects should be considered during system construction. 2.1 System Security Should Be the Top Priority. System security is crucial to the success of urban transportation smart cards. It relates to the vital interests of citizens and passengers, as well as the economic benefits of various operators. During system design, system security must be prioritized. A strict security management system must be established, and a series of standardized requirements must be formulated. This includes preventing attacks on cards, improving the key management system, and strengthening equipment and network security to comprehensively ensure system security. The key management system is a vital component of system security. Since the system is open to various operators, the independence and security of each operator must be considered. This ensures both high key security and facilitates the participation of relevant operators to guarantee the system's reasonable and healthy development. Therefore, urban smart cards must have unified key management standards and IC card structure specifications. 2.2 Determining AFC System Functions Based on the Network Generally, urban rail transit is a network of lines. When constructing the AFC system for each urban rail transit system, an overall system plan is necessary to ensure stable operation and sustainable development. The AFC system is a unified large system within the entire network. Functional requirements should be determined based on the network as a whole, rather than on individual lines. The fare policy for the network must be prioritized, using the most comprehensive possible fare policy as the basis for formulating system functional requirements. This will determine the system's scale, applications, and investment. Even cities just starting construction of their first rail transit line should consider functional requirements from a network perspective, reserving some functions and capacity. It is crucial to avoid building a simple system to meet current needs and then improving it later, as this would lead to significant waste. In terms of system structure, the characteristics of future multi-application systems should be considered. Regarding system scalability and compatibility, the update cycle of electronic and computer technologies and the increase in information volume should be considered. In terms of on-site equipment selection, a forward-looking and user-friendly passenger interface is essential. In terms of system composition, a regional central computer can replace the central computer for each line, improving the level of management and command. 2.3 Coordinate and Promote the Healthy Development of the Urban Public Transportation System The public transportation smart card is a subsystem of the urban smart card system and should also follow the Ministry of Construction's principles of "unified planning, unified card issuance, unified standards, and multi-purpose use" for IC cards. Since IC cards have been used in the "large public transportation" industry (including buses and rail transit) for a relatively long time, and conditions in many places are already quite mature, we can first establish and improve the urban "large public transportation" smart card system. At the same time, considering the compatibility and entry conditions of the urban smart card system, and based on unified principles and standards, we can then expand it to other service payment areas such as gas, tap water, landscaping, community property management, and shopping. It is crucial that, at the outset of establishing the transportation smart card system, all operating parties must start from building a common information platform, fully negotiate the system's functional positioning and interface standards, and make a good overall plan for the system. This will avoid independent actions or preconceived notions, functional deficiencies or incompatibility, and redundant construction and resource waste. Therefore, coordinating the establishment of an efficient and safe urban public transportation system that integrates urban rail transit and ground public transportation is a key focus of our work in the coming period. However, since the system establishment process involves the economic interests of multiple operating companies, in order to effectively promote the smooth implementation of the project, maximize the role of urban public transportation, and realize the city's unified transportation card as soon as possible, strong coordination and support from local governments are needed. Shanghai's work in this regard has yielded significant results. 2.4 Strengthening Information Management and Utilization In the era of economic globalization, it is crucial for enterprises to grasp and analyze market information at any time. The application of IC card technology has opened up vast opportunities for information utilization. While providing convenience to citizens, the unified transportation card system also collects a large amount of public transportation information. Through this basic data, the development trends of various public transportation operating systems can be analyzed, providing decision-making references for the utilization and adjustment of urban public transportation resources, promoting the improvement of urban management levels, and also promoting the improvement of the operation management, service levels, and economic benefits of various public transportation systems, enabling enterprises to embark on a path of sustainable development. Therefore, improving information utilization and enhancing the system's decision-making and analytical capabilities are among the development directions of the AFC system. The system's ability to organize and analyze raw data and information should be strengthened, combining the ticketing system with the network's information management system to identify ticket revenue patterns, providing timely and accurate decision-making and analytical opinions for urban public transportation services and management, and promoting the marketing and promotion of the transportation market. 2.5 Optimization of Maintenance Management Methods With the formation and development of the subway network, products from different companies will inevitably be integrated into the AFC system, leading to an increasing number and variety of AFC field equipment. Due to the large workload and high technical difficulty of software and hardware maintenance, highly qualified system maintenance personnel are required. Therefore, achieving optimal quality and efficiency in maintenance should be a key focus during the continuous development of the subway network's AFC system. The current maintenance management model of the Hong Kong MTR is highly valuable for reference. When a city has more than two subway lines, the subway company should adopt a station-integrated management maintenance strategy. This involves delegating the routine maintenance of many simpler field equipment tasks to general electromechanical workers responsible for station maintenance or outsourcing them, while allowing personnel with AFC maintenance experience to focus on more technically demanding system maintenance and workshop repair work. This fully utilizes existing technical resources and improves operational efficiency. Of course, mastering frontline maintenance of new lines and providing practical experience for new personnel are indispensable to ensure the smooth operation of system maintenance. 2.6 Building New Systems According to Standardization Currently, many places across the country are actively promoting city smart cards or transportation smart cards for local informatization construction, a trend that is both exciting and concerning. While the application of IC cards in my country is developing rapidly, the corresponding technical standards and specifications are lagging behind. Existing systems lack unified coordination and planning, and there are significant differences in the technical standards and levels of systems within the same region or industry. The lack of a unified information platform, a unified key system, and a unified data format results in insufficient system scalability and compatibility, posing considerable difficulties for the implementation of city smart cards and transportation smart cards. Therefore, standardization of smart cards must be given high priority. Currently, the state and industry have established clear standards and specifications for IC cards and related equipment. In future IC card engineering projects, users and system suppliers must strictly adhere to these standards and specifications. To ensure the healthy and stable development of city smart card and transportation smart card systems, it is also necessary to accelerate the formulation and improvement of relevant standards and specifications for AFC systems. During project construction, it is essential to ensure consistency in the system's software and hardware technical standards to facilitate system expansion, updates, and upgrades. System security and product quality should be built on a unified technical standard platform, enabling resource sharing and interoperability. 2.7 Achieving Full Localization of AFC Systems The localization of AFC systems in urban rail transit is a common concern for both users and system integrators. Looking at my country's current rail transit AFC market, the localization of system equipment is progressing steadily. Internationally renowned manufacturers are collaborating with domestic companies to manufacture high-quality AFC field equipment in China, aiming to gain a larger market share. Some core components are also gradually being localized, a very encouraging trend. However, it should be clearly recognized that there are currently no truly mature urban rail transit AFC system software developers in China. This is because developers must possess extensive experience in ticketing management and integrate it into the program design, rather than simply programming according to the client's requirements. Currently, foreign manufacturers do not offer open software design, leading to strong user dependence on them for project maintenance and upgrades, while domestic manufacturers are unable to provide effective assistance. Given this situation, domestic AFC equipment manufacturers and system integrators should proactively seek cooperation opportunities to compensate for the lack of system development capabilities, thereby achieving full localization of AFC systems. It is recommended that domestic manufacturers and system integrators hire internationally experienced AFC system design experts to participate in and guide software design, establish an efficient, practical, rigorous, and comprehensive program library, and gradually achieve the standardization of AFC system software. 3. 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