How Does Suzhou Rail Transit Ensure Traffic Safety?
Traffic safety has become the top concern among the public these days and one of the hot local topics is the reliability of the signal and automatic train protection (ATP) systems for Suzhou rail transit network. The reporter interviewed Chief Engineer Li Jin of Line 1 signal system and he answered some of the most frequently asked questions.
The emergency brake applies to the second train when it enters the " forbidden zone"
Li said the function of the ATP system is to prevent train collision from behind and to ensure traffic safety. Moreover, it can also control the train speed. At present, the top speed of Suzhou Rail Line 1 is 80km/hr and the system will identify and lower down the speed of any train faster than permitted. In case a train moving at a speed of 90km, the system will apply emergency brake to stop it.
ATP, ATS, & ATO Systems Ensure Train Safety
Actually, the entire automatic train control (ATC) system consists of three parts, ATP, ATS (automatic train supervision), and ATO (automatic train operation). The ATS supervises the real-time status of the moving trains, including the distance between two trains, and sends orders from control center to each train operator, while the ATO is the system capable of operating train automatically, including starting and stopping the train as well as opening and closing the doors. Li said the ATO played a supporting role and the trains of Line 1 will have drivers.
Instead of track circuit, Suzhou rail uses wireless technology for two-way communication between the train and ground control center, the latter being the prevailing signal system in global application. Li said the system was imported from Germany and had been proven in many countries as the most advanced and secured technology in the world.
Signal System Installation Completed in SIP Section
Standing on a platform at SIP Jinji Lake West Station, one can see various devices and traffic lights mounted along the tracks. "No train is able to start with the red light on," explained the chief engineer. "This is a chain control process." The light is red when a train stops at the station and will change to green only when all the doors are closed and the train is ready to go at the order of the control center. Moreover, the wireless network used exclusively for train control system is protected by complicated codes from hackers and free from the interference of other networks.
At present, all 11 stations along Line 1 in SIP have completed signal system installation and the technicians are working on other stations in New District and Old City Proper. The next stage is to debug the system to ensure its regular operation. Li said the entire installation would be finished in September and followed by an integrated debugging.
With the wireless communication system, the drivers of two trains can talk to each other without the dispatching center. "There is axle counter on every track and it will tell us the real-time location of every train," said Li Jin. He said that he was confident that the mature information technology, together with the fact that Line 1 is underground and free from the negative impacts of natural elements like rain, thunder, wind, would make the rail transit facility highly reliable and secure.
Originally published on Gusu Evening News
August 5, 2011