Even in the US they can be like that. I just went to Portland, and the MAX trains both run on the street in downtown, with fairly frequent stops, and also on dedicated ROWs outside of downtown, with further station spacing. I remember in San Francisco the Muni Metro also ran in a tunnel under Market Street, but ran on the surface like a streetcar route outside of downtown. I know the MBTA's Green Line also does this on one of the branches, with other branches running on dedicated ROWs