On February 22, 1941, Arturo Toscanini conducted Traubel and tenor Lauritz Melchior in excerpts from Wagnerian operas, including act 1, scene 3 of "Die Walküre" on the live radio broadcast concert of the NBC Symphony Orchestra. RCA Victor later released recordings of excerpts from the concert, as well as a classic studio recording of Traubel in Brünnhilde's Immolation Scene from "Götterdämmerung". Traubel later triumphed in "Tannhäuser" and in "Tristan und Isolde". She was renowned for her powerful voice, which was often described as a "gleaming sword"; her endurance and purity of tone were unsurpassed, especially as Brünnhilde and Isolde. Although she longed to sing Italian opera, she never appeared in an Italian opera performance onstage, although she often included Italian arias and songs in her recital repertoire. Towards the end of her career at the Met, she added the Marschallin in Richard Strauss's "Der Rosenkavalier" briefly to her repertoire.