Abstract

All stations along the metro line, the control center, and the vehicle depot require a unified time‑synchronization infrastructure to support train dispatching, signaling systems, and passenger‑information display screens. Zhongxin Chuang provides this solution. DNTS Beidou Master Clock Series + A comprehensive suite of digital sub‑clocks and a complete clock‑synchronization solution, with the entire system certified for reliability by leading authorities in the rail transit industry. It enables unified clock synchronization across all stations along the line and is supported by a network‑wide time‑monitoring platform for remote operations and maintenance, covering all scenarios—including station platforms, waiting halls, dispatch control rooms, and vehicle depots—and suitable for both new metro projects and clock‑upgrade initiatives on existing lines.

I. Core Business Requirements for the Metro Line-Wide Clock System

1. Unified time across the entire network: All station sub‑clocks, dispatch large displays, signaling interlocking systems, and public address systems are fully synchronized.

2. High-reliability continuous operation: The subway operates year-round without interruption, and the clock system… 7×24 Operates continuously for hours, with seismic resistance and wide-temperature compatibility to suit underground station environments;

3. Remote centralized operations and maintenance: Hundreds of sub‑clocks across the entire line require no manual time synchronization at each station, with online fault monitoring and unified remote configuration.

4. Scheduling Coordination: The master clock synchronously outputs standard time to the train signaling system, ATS Automatic Train Supervision system, ensuring the safety of train dispatching;

5. Industry Compliance: The system has passed reliability testing for rail transit equipment, meeting the acceptance criteria of subway design specifications.

II. Overall Architectural Design of the Complete Clock System

1. Control Center Primary Master Clock: Primary and backup units are deployed in the Line Dispatch Center’s equipment room. DNTS The multi-mode Beidou time server serves as the system’s primary timing reference, receiving standard time signals from Beidou satellites.

2. Secondary master clocks at each station: A compact unit is deployed in the equipment room of every station. NTP From the clock, receive the time signal transmitted by the primary master clock at the control center.

3. Station terminal clock networking: On the platform, in the station concourse, and in the dispatch room, time‑division, full‑information, temperature‑and‑humidity‑monitoring multifunctional digital clocks are deployed and synchronized to the local slave master clock via the station’s LAN.

4. Scheduling system synchronization link: primary master clock output IRIG-B、 NTP Signal Access ATS Train dispatching, signal interlocking, and video surveillance systems;

5. Line-wide centralized operations and maintenance platform: All master clocks and slave clocks are connected to an intelligent, network-wide unified time monitoring platform, enabling the control center to centrally view the operational status of all equipment across the entire line.

III. Selection and Matching Criteria for Master Clocks and Digital Sub‑Clocks

1. Master Clock at the Line Control Center: DNTS-9D High-capacity data center‑class servers, supporting concurrent synchronization across all sites and the entire service line.

2. From the master clock at a regular station: DNTS-9-B A single‑北斗 economical server that meets the synchronization requirements of standalone terminals.

3. Subway platform clock: displays hours, minutes, and seconds. LED Sub‑clock, wide‑temperature range, waterproof and dustproof, visible in bright light;

4. Data center clock: a multifunctional digital sub‑clock with integrated temperature and humidity monitoring, facilitating environmental monitoring in the server room.

5. Vehicle Depot / Office area: Use low-cost, time‑division simple sub‑clocks in combination with round‑face analog clocks.

IV. On-site Deployment and Implementation Process for the Metro Project

1. Control center equipment room construction: installation of primary and backup master clock cabinets, erection of a Beidou satellite antenna on the rooftop, and associated supporting facilities. DNSIS Interference with protective signals of the isolation device;

2. Network cabling at each station: Establish an independent local area network for the station and install network cables to connect the master clock with the digital sub‑clocks at all locations.

3. Cross-site network configuration: Establish dedicated lines from the control center to each station and configure them. NTP Inter-segment synchronization policy;

4. Dispatch system integration and debugging: Completed the master clock and… ATS , Interface alignment of the signal system’s time‑frequency interface; testing for timing synchronization consistency.

5. End-to-end joint commissioning and testing: The network-wide monitoring platform has been activated, and each station has been tested for sub-clock synchronization status and fault alarm functionality, continuously… 72 Hourly full-line stable operation testing.

V. Post-Implementation Operation and Maintenance Management Mechanism for the Metro System

1. Remote Operations and Maintenance at the Control Center: Operations personnel use the monitoring platform to view the online status and synchronization offset of all sub‑clocks in real time, with automatic fault alerts.

2. Quarterly station inspections: Conduct on-site verification of antenna signals and sub‑clocks each quarter. LED Display the operating parameters of the master clock in the equipment room;

3. Line capacity expansion and compatibility: Newly added stations and platform‑level time‑display clocks can be directly connected to the existing master clock, eliminating the need to modify the primary master clock at the control center.

4. Rapid fault resolution: Remote diagnosis of black‑screen or network‑disconnection issues; on‑site replacement of the entire unit, with no impact on clock synchronization across the entire line.

VI. Application Outcomes of Implemented Projects

Several lines of the Hangzhou Metro and the Shanghai Metro have adopted the Zhongxin Chuangcheng master clock system. + The digital sub‑clock system ensures unified time synchronization across more than a thousand sub‑clocks along the entire line. Remote centralized monitoring from the control center significantly reduces the frequency of manual inspections at each station, while maintaining stable timing for train dispatching and the signaling system, successfully passing the rail transit industry’s reliability acceptance on the first attempt.

Conclusion

Beidou Master Clock + The digital sub‑clock synchronization solution is tailored for new and upgraded metro projects, addressing three core requirements—train‑operation dispatch safety, passenger‑oriented visual time‑keeping guidance, and centralized remote operations and maintenance—and constitutes a comprehensive, standardized clocking system for urban rail transit.