NEW : All 24 passengers are safely on the ground , fire chief says . The Joker 's Jinx roller coaster stops on the tracks at Six Flags America . Comment: No one is injured , all riders `` are secure '' The ride will closed while officials investigate , she says .
NEW : All 24 passengers are safely on the ground , fire chief says . The Joker 's Jinx roller coaster stops on the tracks at Six Flags America . Six Flags spokeswoman : No one is injured , all riders `` are secure '' The ride will closed while officials investigate , she says .