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Signal control system for subway No 1

Location / Country : Beijing DaCheng Signal & Communication Co., Ltd.China

Product Solutions:
EDS-505A/EDS-508A Series

5 and 8-port managed Ethernet switches

Project Introduction

Subway No. 1 from Liuyuan to Shuanglin has a total length of just over 26 km, including almost 14 km underground. The subway has 23 stations, one train-distribution center, one train storage area, and a distribution control center. The trains use 750 VDC third-track power. To give you an idea of the complexity of the system, there are 4 bulk substations, 6 propulsion power substations, and 3 voltage-reduction substations, with signals transmitted by an ATP, ATS system. The trains are domestic and DC voltage powered. With a total of 156 trains, waiting time is only 2 minutes between shuttles, while serving 48,100 passengers each hour.

A subway system has many different sub-systems, including Environment Monitoring Control System (EMCS), Fire Alarm System (FAS), Fire Extinguisher System (FES), Supervisor Control And Data Acquisition (SCADA), Automatic Fair Collection (AFC), and Distributed Supervisor System (DSS). DSS is the most important of these. The core of DSS is the link system on the railway. The reliability, security, stability, and immediacy affect railway safety.

 From a technical aspect, the signal system for the railway is a computer link system, which is a combination of the mechanical link system and electrical link system (relay link system). Due to the unreliability of the computer link system, the devices must be highly reliable. In particular, the network system must have redundant and interference-free functions. What kind of network system has such functions?

Moxa Solution

The signal collection and link devices use equipment from the British company, Westinghouse. The company is well-known around the world for producing reliable and stable devices. In the subway, eight out of twenty one stations are equipped with WOC signal collection devices, and four out of these eight stations have two signal link devices. WOC and link devices are used for signal collection and on-site control, respectively. The highly reliable front-signal-link-devices must be connected in a safe and reliable network system to communicate with each other. In addition, the system needs devices with a wider bandwidth to achieve efficient communication and immediacy when collecting signals for distribution. The media redundancy, 260,000H MTBF, and 148,800 pps forwarding and filtering rate of Moxa EDS-508-SS-SC can satisfy the system's critical requirements.

Network diagram for subway signal control system

Why Moxa

  • Moxa Turbo Ring supports fast media redundancy (under 300 ms) to activate the backup path, helping to ensure the security of the network system.
  • In addition to configuring and managing EDS-508-SS-SC over the web, engineers can also monitor port status by SNMP-OPC Server.
  • EDS-508-SS-SC is equipped with signal mode fiber ports and can communicate end to end over a distance of 15 km.
  • The non-fan and low-power design ensures a 260,000 hour MTBF for EDS-508 series.
  • EDS-508 series has an automatic warning function that operates by email and relay outputs.


See More Real World Applications
Moxa’s solutions are deployed in major railway systems across Europe, the US, and Asia, and can be found in passenger information systems (PIS), automatic train control (ATC), automatic train operations (ATO), automatic train supervision (ATS), and CCTV systems. For more information, please click on the icon to download the railway success stories.