Safety tests of fully automated Metro trains in Shanghai

With over 800 kilometres of track, it’s the longest underground railway network in the world. Moreover, no other underground railway boasts as many passengers: some 3.88 billion passengers use it every year, with over ten million people on average taking the underground every single day. TÜV NORD China has undertaken an independent safety assessment under CNAS accreditation (ISA) for the fully automated line 18. For the last 3-and-a-half years, the railway technology team has been closely scrutinising the 50 train units.

As the vehicles at issue consist of 50 complete trains of the same type, type testing was carried out. The documentation for these trains also had to be scrutinised, and inspections in the factory itself were also on the agenda: the units were made by CRRCZELC in Zhuzhou in central China. “Alongside the on-site inspections, we also ran remote inspections using a new method. This entailed our expert on the ground controlling the camera, with additional specialists assessing the recordings from the office,” railway expert Gene Wang explains.  “This has proved its worth for particular tasks.” What makes this project especially interesting is the fact that the trains involved are fully automated (GoA4), which is why the interactions between the trains and the signals, power supply and infrastructure were also tested. For the specialists, the emphasis was very much on safety during the ISA inspections; also taken into account at the same time was the operator’s desire for increased availability of the trains.

Reconciling these two requirements was made possible by the special approach adopted during the independent safety assessment, which is prescribed by the European Committee for Electrotechnical Standardization (CENELEC) These assessments are based on the EN 50126, 50128 and 50129 standards, which are concerned with the development of electrical, electronic and programmable systems that perform safety functions. These standards regulate functional safety for the railway sector in accordance with the IEC 61508 standard. Reliability, availability, maintenance and safety – RAMS – are the focal points of the inspection of the individual vehicles. To assess RAMS, systematic analyses are carried out to identify risks to functional safety and, as a second step, to come up with  options to counter them, be these construction-related or organisational in nature. The task at hand is therefore to investigate the likelihood of occurrence of such events, as is standard practice in the railway technology sector. Further analyses concern the software used, alongside safety-related aspects of individual subsystems and the railway signalling system over the entire service life of the vehicle.

Final acceptance tests at the point of commissioning rounded off the work; these included the interaction between the trains and the platform doors and camera surveillance. Wang: “For the independent safety assessment we looked at the trains and their interfaces with other systems.

Shanghai’s Metro is a magnet for superlatives: it is the third oldest underground railway in China but is also constantly being modernised. At over 800 km in length, the system boasts the longest underground network in the world, and there are plans to extend it yet further, to over 1,000 km, by 2025. The 396 stations are currently served by 19 lines. By passenger volume it is the world’s second largest Metro network. Most of the lines are semi-automated (GoA2); five of them, including the new line 18, operate fully automatically without personnel. The fully automated part of the network is 164 km long, the second longest of its kind in the world. The trains which are being tested have been earmarked to serve the 38.9 kilometre line from Yuqiao in the south to Changjiang Road with its 18 stations. A further extension of the line to Dakang Road is currently being planned.