The Niagara class was a 24th-century Starfleet design with three warp nacelles, known from the wreck of the USS Princeton among the ships destroyed at Wolf 359.
The class appears in The Best of Both Worlds, Part II, in the field of wreckage left by the Borg at Wolf 359. One of the destroyed ships combines a saucer and a compact secondary hull with three nacelles, two above and one below.
The name is not given in dialogue. Production sources and reference works identify the wreck as the USS Princeton and the type as the Niagara class, and also assign to it the USS Wellington, the ship on which Ro Laren served before the Garon II incident.
The model was one of several built quickly from kit parts for the graveyard scene.