We refer to Ms Claire Huang’s article (Safety under spotlight after trains collide in Hong Kong, 18 March 2019).
The Land Transport Authority (LTA) is concerned and we are closely monitoring Hong Kong MTR’s investigations into the collision of two Tsuen Wan line trains on 18 March 2019. Initial reports indicate that the issue is linked to a software problem with the Tsuen Wan line’s new signalling system during the testing phase.
While the developer of the signalling system, Thales, also developed the new Communications-Based Train Control (CBTC) signalling system for Singapore’s North-South and East-West Lines (NSEWL), it is important to note that there are many versions of the SelTrac system built by Thales. No two CBTC systems are identical as they need to be custom-built. Each metro uses a unique system architecture, with software logic that is customised for the local environment and infrastructural conditions.
The SelTrac system has been in existence for many decades and has been adapted for 86 metros in 40 different countries, including multiple lines in London, Shanghai, Dubai, Toronto and Vancouver.
Based on preliminary information, the causes and conditions leading to the Joo Koon station incident in late 2017 are completely different from what happened in Hong Kong this week. What we faced was due to interface issues between the NSEWL’s legacy and new signalling systems. Immediately after the incident, LTA and SMRT delinked operations between the two systems to decisively remove this risk. LTA also invited Thales to set up a CBTC simulation laboratory in Singapore – the first-of-its-kind in Asia. This has allowed LTA and SMRT, since April 2018, to perform additional tests to fine-tune the new signalling systems’ software and hardware before it is implemented on our rail lines.
The NSEWL has seen an improvement in Mean Kilometres Between Failure (MKBF) from 115,000 train-km in 2017 to 556,000 train-km in 2018. The NSEWL has been operating entirely on the new CBTC signalling system since May 2018.
Chua Chong Kheng
Deputy Chief Executive, Infrastructure and Development
Land Transport Authority