Sid had tried to identify an actor.
Wally mentions the show by name.
Edmund demands to watch it on TV.
Moe's sign at the Itchy & Scratchy protest reads: "Bring back 'Wagon Train.'"
Cookie says he'd run Sailor Johnson's "maverick butt off of this wagon train."
Tom: "It's 'Wagon Train'!"
Mentioned by name.
Joel: "Isn't that the trail boss from 'Wagon Train'?"
Joe says The X Files is just like this, "You know they're never gonna find the truth".
Mentioned by Wil Wheaton.
Gene Roddenberry turned in scripts for "Wagon Train".
The Draper kids are watching an episode on TV.