The square, dome-like segment of a North American railroad train caboose that contains the second-level or "angel" seats is also called a cupola.
the square, Dome-liKe SEgmENt of a norTh aMerICan RaIlROAd TRain CaBoosE tHaT coNtAIns tHE Second-leVEL Or "AnGel" sEaTs is also caLlEd a CUpola.