The composition of train tracking interval is analyzed in depth with comprehensively considering of various influencing factors, including train performance, line conditions, signal system, transportation operation. Train tracking interval is accordingly decomposed into train performance operation time, additional operation time under line conditions, additional operation time under signal system and other additional operation time. Definitions of each operation time and its contribution rate to train tracking interval are proposed. Taking CR400BF EMU and its operation parameters as an example, the contribution rate of each operation time to each train tracking interval is calculated using simulation calculation software, under the combination conditions of different operation speeds, different gradients and different block section lengths. The influence of each factor and its combination on train tracking interval is quantitatively analyzed. Conclusion: For train interval tracking time and train passing tracking interval, the leading factor is signal system when the operation speed is low, and the leading factor is train performance when the operation speed is high. For departure tracking interval and arrival tracking interval, the leading factor is line conditions.

To further extend the automation scope of the high-speed railway ATO system, a brief analysis of the high-speed railway automatic turn-back operation scenario is presented. Based on the high-speed railway ATO system, a scheme is proposed to add the automatic turn-back function, and the interfaces and functions of the ground equipment, the head on-board equipment and the tail on-board equipment are defined and assigned. The different state transitions during the automatic turn-back process are described. Based on the semi-physical simulation platform, the scheme is experimentally verifi ed and the results prove its eff ectiveness.

With the issuance of the development plans for core metropolitan areas in China, and the acceleration of the construction of suburban railways that expand the urban framework, there is an increasingly urgent demand for the selection of signal system modes for suburban railways. In view of the status and technical specifications of the signal system industry, the main signal system modes selected for suburban railways are CTCS-2+ATO system, CBTC system, etc. Therefore, a sufficient discussion is needed for the selection of and integration between CBTC system for metro lines and CTCS system for national railways. The two systems need to be comprehensively considered in terms of onboard equipment architecture, wayside equipment, system software and hardware, communication protocol, etc. This paper discusses the possibility of integration and interoperability between CTCS-2 and CBTC on the basis of the requirements for the selection of signal system modes for suburban railways. It proposes relevant designs and conducts feasibility analysis for three different schemes, i.e. CTCS-2 and CBTC fully integrated with each other, interoperable with each other and switching between each other. In particular, it performs research and analysis in terms of the interoperability scheme, interfaces, switching area, switching process, etc., and provides detailed schemes, on the basis of the requirements for interoperability. The interoperability scheme is found to be more feasible than the full-integration scheme.

This paper takes the exploration of the application of 5G in Nanjing Metro as the starting point, makes use of the high bandwidth and low latency characteristics and resource isolation means of 5G on the public network to empower the urban rail transit industry, covers all the scenarios of rail transit, creatively proposes a cross-industry business model, explores a green and low-carbon development path suitable for the urban rail transit industry, and achieves noticeable results in the coordinated development of digitalization and greenization, promoting the high-quality sustainable development of the urban rail transit industry.

In order to meet the demand for centralized control of CTC central stations of common speed railways and realize the goal of reducing personnel and increasing effi  ciency in modern railway transportation, the CTC regional centralized control system scheme can be deployed according to the transportation demand of lines and stations on the premise that the overall system structure and operation organization principle of CTC remain unchanged. Through in-depth analysis of CTC regional centralized control system structure, system function realization and system deployment scheme, this paper discusses the system function realization, project implementation and the improvement eff ect on railway construction and operation benefi ts. It provides support and reference for the high-quality development of railway transportation in China. 

According to the network and public transportation characteristics of the metropolitan area rails, the technical goal of integration of signaling systems is proposed, which is, the integration of existing C2/C2+ATO and CBTC systems and the integration of signaling systems using new interconnection technology. Based on the analysis of differences in technical level, working mechanism and system function between the ground and vehicle equipment of the existing mainstream CTCS and CBTC systems, the interconnection schemes of "ground-to-vehicle compatibility" and "vehicle-to-ground compatibility" are proposed. Combined with the current researches of relevant manufacturers, the new interconnection technology route of suburban railway is analyzed.

The ZDJ9 AC five-wire switch control circuits exhibit the phenomena of arcing, burning, and oxidation of the first and second groups of strengthening contacts of the 2DQJ relays, resulting in poor contact of the contacts. Due to the fact that the first group of front contacts and the second group of rear contacts of 2DQJ relays are shared contacts, oxidation of these contacts can lead to loss of indication of a switch ; at the same time, there is a risk of instantaneous starting current striking and damaging outdoor diodes, which can also lead to loss of indication of a switch. The principle of the switch control circuits is analyzed, the circuit logic is adjusted, and the ZDJ9 AC five-wire switch control circuits are optimized to avoid loss of switch indication failure and improve the overall reliability of the switch equipment.

The paper briefly introduces the function and structure of CTCS+ATO train control system, analyzes and proposes the optimization items to be carried out for the application of CTCS2+ATO train control system in suburban railway train control system. Reducing the tracking interval time, shortening the effective length of the arrival and departure track, supporting "four networks integration", and supporting multi-mode Train-to-Wayside Communication(TWC) are analyzed and discussed respectively. Further, combining with the existing research results, some recommendations and solutions are proposed.

When it is not possible to install a distant signal between two adjacent railway stations, a liaison circuit between the stations can be used as a block device. This paper mainly studies the typical problems that involve the acquisition drive circuit which occur when Computer Based Interlocking (CBI) is combined with the liaison circuit between the stations, including the problem of automatic reversal of section direction when the CBI system of the receiving station restarts, and the problem of“double approaching” when a departure route is set and then immediately canceled.This paper analyzes the causes, and puts forward improvement ideas and specifi c solutions in order to provide reference for similar engineering problems. 

This paper analyzes the characteristics of acquisition of functions in the technical conditions of the centralized signal monitoring system and verifies the analysis results through on-site trial in specific projects. In this way, it seeks to find installation methods to greatly improve the product quality of the centralized signal monitoring system. Decentralized installation means installation  nearby monitoring objects, this installation method will shorten the monitoring and acquisition wirings and reduce the safety risks. Preinstallation at the factory will advance the field wiring to the assembly and prefabrication stage, which improves accuracy and achieves standardization. The installation method combining these two has been proved to be an effective approach.

According to the definition of main line and the provisions of signal aspect and indication in Technical Management Regulations for Railway (High Speed Railway) (TG/01-2014) and the provisions of temporary speed restriction design in Technical Specification for Temporary Speed Restriction of Train Control System (Q/CR 662-2018), this paper analyzes that the line design and signal design are not unified for the processing of main line in the station, It is the reason why the speed restriction cannot be issued, and explores reasonable solutions.

Railway signal circuits are used to control signal equipment to ensure driving safety and improve transportation efficiency with safety and reliability. However, in the actual use of relay circuit equipment, it is possible that the circuits fail to respond in a safe manner in the event of failure. This paper analyzes the potential unsafe factors in signal circuit design, conducts research and fault hypotheses, analyzes the risk factors of circuit design, eliminates loopholes and hidden dangers through checking and benchmarking, prevents problems before they occur, and ensures that the signal circuit design conforms to the "fail-safe" principle. 

The fully automated FAO system for urban rail transit is a highly comprehensive large platform system, and a cutting-edge technical innovation in urban rail transit. The engineering design liaison is a key link for the implementation of new technologies in specific projects. Focusing on fully automated systems, this paper explores the importance of engineering design liaison from the perspective of urban rail transit operators, and describes and analyzes the key issues for urban rail transit operators in the engineering design of fully automatic systems.

Starting with adding the section logic inspection equipment, this paper analyzes the reasons for the phenomenon that the block section in rear of the home signal is cleared later than the section in rear of the home signal and cannot be unlocked normally after adding the equipment, and puts forward measures and suggestions to improve the circuit diagram design, so as to ensure the interlocking safety and reduce the impact on transportation. It has practical value and significance of easy operation and promotion for the design, construction, maintenance and operation units in their daily work.

There is a need to upgrade the maintenance measures associated with balise equipment, by improving the management method of balise telegrams dominated by manual operation, to continuously enhance management efficiency. To this end, this paper studies the management of balise telegrams. It briefly describes the main functions and roles of the balise telegram management system. Then, it analyzes the overall requirements for the balise telegram management system, proposes an overall design scheme, and elaborates on the network structure design and functional module partition of the balise telegram management system. Moreover, it describes such issues as the relevant technologies and specific data structures, module functions and operation interfaces to implement the software. Thanks to the intelligent management system of balise telegram based on real-time parameterized data, a whole-process safety management system of balise telegram has been established, with the railway bureau performing the integrated management, and the signaling personnel at all levels performing the dynamic management of the balise telegrams under the "cloud-edge" collaboration framework, to provide reliable guarantee for the safe train operation of high-speed railways.

Based on Qingdao Line 6 project, this paper proposes a fusion technology of signal and vehicle, which redefines the boundary of signal and vehicle. With the goal of "safety, reliability, efficiency, convenience, green and environmental protection", it focuses on the intelligent upgrading of rail vehicles and on-board core systems, and constructs an integrated solution of intelligent train control. The fusion system includes the following functions and optimization: single vehicle and multi-vehicle energy-saving operation control function; integrated intelligent vehicle control optimization; integrated full-automatic coupling and uncoupling function; real-time tracking and guiding function of passenger capacity; integrated intelligent self-test function. This paper introduces the design and implementation of the fusion control technology of urban rail transit signal and vehicle in detail.

This paper introduces the construction background of intercity railway in Shenzhen Metropolitan Area and the operation and maintenance status of the signaling system, proposes the construction goal of the integrated intelligent operation and maintenance platform. By analyzing the operation and maintenance requirements of the equipment, a set of specific software and hardware construction schemes are given. After the completion of the platform, it is conducive to comprehensively improving the O&M and management level of the equipment, and is also conducive to the integration and optimal configuration of data resources.

When there are asymmetric high-voltage pulse track circuit and 25 Hz phase-sensitive track circuit in the main line of the station at the same time, due to the inconsistent time characteristics of the two track circuit systems, there are phenomena of missing unlocking, train loss and code loss in the track section during single locomotive operation, causing interference to normal train operation. By analyzing the time characteristics of the two track circuit systems in detail, this paper analyzes three operation fault scenarios, and gives different solutions for each scenario, which has certain guiding significance for future engineering design.

High-speed railway communication optical cables carry information such as train dispatching, command and control, which are an important part of ensuring the safety of high-speed railway transportation. Therefore, the analysis and handling of optical cable faults is particularly important. Through the summary of years of on-site maintenance experience, the analysis and handling methods of optical cable faults are derived, which are helpful to quickly judge and solve optical cable faults and are able to provide a reference for the maintenance of high-speed railway communication optical cables.

The signal systems under the traditional architecture have a high degree of independence and cannot achieve information fusion among multiple systems. In order to realize information sharing with the urban rail production network and enable big data mining, the signal ATS subsystem can be included in the urban rail cloud platform. On the basis of ensuring the independence and safety of the core equipment of the signal systems, the ATS subsystem center-level servers and workstations are included in the cloud platform. This paper calculates the computing resource requirements of the ATS subsystem with a reuse ratio of 1.0 as an example. The connection between the cloud part and the non-cloud part of ATS is realized through the core switching network of the cloud platform. The application server and interface server are configured with blade servers, and the database server is configured with a rack server. To meet the requirements of ATS subsystem redundancy and undisturbed switching, the cloud platform provides two sets of server resources with the same configuration for the ATS subsystem. Considering that the urban rail signal systems need to meet the requirements of Level 3 of Information Security Level Protection , the cloud platform should also be built according to Level 3.