Question:  The Mark VI monorail (or M-VI) is a monorail train used in the Walt Disney World Monorail System and the Las Vegas Monorail which connects several large casinos in what 2 unincorporated communities in Clark County, Nevada?
Sentence (from "Mark VI monorail"): The Mark VI started replacing the Mark IV monorails at Walt Disney World in 1989, replacing the final Mark IV by 1991.
Relevant evidence: No