A two-hour window to maintain the network each night
At 2 a.m., the video shows an army of highly skilled mechanics descending into the tunnels of Hong Kong's subway. They have just two hours before commuters begin pouring into the stations.
The margin is narrow. If a single task overruns by 15 minutes, the video says, the entire city could grind to a halt. Even so, the narration states that 99.9% of journeys run on time, a reliability it attributes not only to human effort but to predictive AI and thousands of sensors that catch mechanical faults before trains break down.


