The force said on Thursday evening that it had received a report at about 2pm the previous day that the two men had forced their way into the depot by cutting sections of barbed wire at the top of its walls.
They allegedly spray-painted each of the carriages with a five-metre-by-one-metre graffiti design in green, yellow and pink.
“By going through vast amounts of CCTV footage … and intelligence analysis, police successfully arrested two suspects in the restricted areas of the airport who were waiting to board at around 8pm on the same day, six hours after the report,” Chief Inspector Chan Chi-leung said.
The force identified the suspects as a 34-year-old Australian and a 30-year-old American. They are currently in custody under investigation.
Officers said the pair left behind nine cans of spray paint, a wooden ladder and two high-visibility vests as they fled after being spotted by staff. They allegedly scaled a three-metre-high wall before running off towards Shing Tai Road.
