A step up from sitting in coach, where you get a regular train seat, a Roomette is a private space with a door and blinds to cover up the windows.
Inside, there are two seats across from each other, a table that folds out in-between, and a bed above the seats that pulls down. The seats also pull out into a bed.
And in some Roomettes (mine included), there's a side table that swings open to reveal a toilet. Above, there's a folding sink and mirror.