The MTR Corporation has made public the results of its investigation into the Tsuen Wan Line (“TWL”) incident which occurred during a drill for the new signalling system at non-traffic hours on 18 March 2019.
It was concluded that the incident was caused by software implementation errors made by the contractor of the new signalling system, Alstom-Thales DUAT Joint Venture, during the process of performing a software change. A number of improvement measures have been recommended for the contractor.
During the drill conducted on TWL in non-traffic hours on 18 March 2019, an MTR non-passenger train was entering Central Station through a crossover when it collided with another non-passenger train that was departing from Central Station through the same crossover. MTR set up an Investigation Panel and looked into the cause of the incident and made recommendations for preventing the recurrence of similar incidents.
Dr Jacob Kam, Chief Executive Officer of MTR Corporation said, “For a corporation that always puts safety as our top priority, we take every incident which has an impact on the safety of people inside MTR premises very seriously and would spare no effort in identifying the cause and looking at ways to prevent any recurrence. We will make sure all necessary improvements are made by vigilantly monitoring the contractor to implement necessary follow up work and enhancing our own monitoring system.”
After the incident,the contractor has replaced the software design and development team who caused the software implementation errors. To enhance the software development quality and prevent the recurrence of similar incident, the Panel recommended the contractor to adopt different improvement measures, including:
- Fix the software issue and confirm with substantiation that there are no wider implications in software development quality;
- Enhance the software coding and testing practices to avoid future programming errors, and introduce effective and traceable measures for detection of any programming errors;
- Employ an external Independent Software Assessor (“ISA”) to enhance the software development process for the signalling zone controller computers; and
- Review, re-check and demonstrate robustness on its approach with traceable evidence in applying a fail-safe principle.
Additionally, the Panel recommended MTR to adopt measures, including but not limited to, expanding the scope of the ISA from the safety assurance for passenger service to the inclusion of on-site train related testing certification etc.
The MTR Corporation will oversee the contractor in implementing the improvement measures, and will exercise extra vigilance and strengthen monitoring on the contractor’s deliveries.
