What fake name does Holden use with Ernest Morrow's mother on the train from Pencey?

Holden uses the fake name Rudolf Schmidt when he meets Ernest Morrow’s mother on the train from Pencey.

The scene occurs after Holden has been expelled from Pencey Preparatory School and is traveling toward New York City. When the woman notices the Pencey sticker on his luggage, she identifies herself as Mrs. Morrow, Ernest’s mother. Holden does not give his real name; instead, he introduces himself as Rudolf Schmidt.

Rudolf Schmidt is not a random invention. Holden says it is the name of the dormitory janitor at Pencey. He then launches into an elaborate series of lies, praising Ernest as unusually popular, modest, and sensitive, even though Holden privately considers Ernest one of the school’s most unpleasant students.

The episode highlights one of the novel’s central ironies: Holden condemns other people for being “phony,” yet he repeatedly lies himself. The other options are real names from the Pencey world, but they belong to different characters or situations rather than serving as Holden’s alias in this train encounter.