Chinadidn'thaveahigh-speedrailfiveyearsago.Butnowtheticketsofhigh-speedtrainsareusuallysoldoutveryquickly,eventhoughthedepartureintervalisquiteshort.AndpeoplecanconvenientlytravelaroundthenationataspeedthatdoublesthespeedofthefastestAmericantrain.Theoperationofhigh-speedrailsystemisverysuccessful;itcarriestwiceasmanypassengersasthenation'scivilaviationsystem.Chinahasoneofthemostadvancedrapidtransitsystemswithlowemissionsintheworld,anditonlytakesfiveyearstoachievethis.