During the Spring Festival holiday from February 10 to February 17, the entire Shanghai Metro network transported a total of 39,183,100 person-times. In the network, Shanghai Metro Line 2, which connects the two major transportation hubs, Pudong Airport and Hongqiao, is a well-deserved "backbone", carrying a total of 5.39 million person-times in 8 days, accounting for 13.76% of the total passenger flow of the network.

But when many tourists shuttled among Shanghai's business districts and attractions, or when out-of-towners returned to Shanghai from faraway places, no one would know that the 23-year-old Line 2 had just undergone a sophisticated "heart surgery".

On the early morning of January 27, the first phase of ATO (automatic train operation) cutover of the new CBTC system on Line 2 was successfully completed. It only took 26 minutes to realize the "senseless" switching of the signaling system. This marks that Line 2 has officially launched a new model of "dual system dual standby” and become the world's first metro line to realize dual-system operation.

The cutover of the new CBTC system is completed

In the future, Line 2 will be equipped with both the new CBTC system and the original TBTC system for daily operation. When necessary, one-click senseless switching between the two systems can be achieved. With the support of the new system, the minimum operating interval can be reduced from the original 2.5 minutes to 2 minutes, and can even be shortened to 100 seconds in the downtown during peak hours.

A "customized solution" for signaling system renovation with innovation

The Shanghai Metro Line 2 signaling system renovation project is the world's first multi-mode train control system renovation, which enables seamless switching between two signaling systems of different eras, different standards, different manufacturers, and different designs. It's just like making both systems master "two languages" to achieve barrier-free communication.

This is an innovative system renovation plan "tailored" by CASCO and Shanghai Metro for Line 2.

As the busiest rail transit artery in Shanghai, Line 2 has a maximum daily traffic of 1.82 million person-times. The previous generation of TBTC signaling system is increasingly struggling to satisfy the rising operational demands. CBTC, as the most mainstream signaling system in the world, naturally becomes the best alternative. However, if CBTC is used to completely replace TBTC, the system cutover will be difficult, and all equipment in the later opened sections of Line 2 will be eliminated, which will inevitably lead to a waste of investment. Therefore, Shanghai Metro and CASCO jointly discussed and decided to boldly try to add a new CBTC system to the existing TBTC system without affecting the daily operation. The two systems will serve the line at the same time and complement each other.

The successful completion of this renovation project marks another successful innovation of CASCO in the field of rail transit renovation. The successful application of the new technology not only breaks through the traditional model of signaling system renovation, but also provides new solutions and reference models for metro overhaul and renovation in the industry. Furthermore, it is of important technical guidance and enlightening significance for exploring the integrated development of train control system under the background of "four-network integration" of China's rail transit.

Renovation commissioning rehearsed for senseless transition through refined management

The system cutover, empowered by digital means, connected all 58 operation points on the whole line, and covered 18 centralized stations, 12 non-centralized stations, 3 depots, 30 stations, 76 trains, and 480 screen doors on the main line. The cutover is like "senselessly" implanting a new blood vessel in a beating heart. While the normal "blood supply" of the original signal TBTC system of Line 2 is maintained, this surgery allows seamless switching to the newly implanted CBTC system.

On-site commissioning

Not only that, the principle of "senseless changeover" has been stressed in the implementation of the renovation project in the past three years. The project team took advantage of the extremely short night maintenance time after the operation to carry out more than 580 debugging activities and trials without occupying the operation time.

Since the completion of the cutover, the overall punctuality rate and performance rate of Shanghai Metro Line 2 have been well above 99.5%. In the next stage, CASCO will work with Shanghai Metro to accelerate follow-up works and continue to guarantee the safe and efficient operation of Shanghai Metro.