When travelling on the MTR, we sometimes hear the announcement that there is
a signalling failure causing delay. Why does it not affect safety?
The signalling system is designed and operated under the "fail-safe" principle.
The "fail-safe" feature ensures that, in the event of a signalling failure,
the system will respond in such a way that it will cause no harm to other devices
or danger to personnel. Very often, this will cause stoppage of trains and hence
prevent the occurrences of hazardous conditions that may arise due to train movements.
Hence, safety of passengers is always protected.