baffle gate bags closed control covered entrance exit faregate gate gates hooded hoods mass transit stations mass transit turnstiles movement control not used one-way people traffic passenger control passenger movement passengers pedestrian control railway station sealed signs turnstile turnstiles waist-high turnstiles adults barrier barriers ccrowds controlled controlling crowd entering families gathered gathering guided guided-movement large-crowd men mobile-barriers movement on-the-move pedestrians people public shadows shelter sheltered sunlight sunny sunshine thoroughfare underpass visitors walkers walking women active activity angles appearance body-parts clean-hands close-up computer computer-mouse finger-nails fingers grip hand holding mouose-pad mouse sleeve work access alert authorities authority availability available boat boating-control communicating communication deployment equipment fast flag foam froth Hong-Kong law law-&-order light naval observation on-duty on-the-job order patrol patrolling power presence regulations responsibility responsible sea secure security speed transport wake water watercraft white aircraft anchored balloon cable checks circular colors colours duty-pilot engineers fabric filled flight-operation gondola height helium helium-balloon high inspected inspections large limited mesh metal-cable metal-line monitored monitoring motion net pilot piloted registered ride safe safety secured sights sightseeing Singapore tethered tourists views weather-limits wind-limits