The penultimate episode of Trackdown Season 1, "The Brothers," is a very entertaining episode not so much for Steve McQueen, but for Richard Devon in the role of Fenn.
Hoby is ambushed on his way to pick up a prisoner and relieved of his gun and credentials. Upon his arrival in the town, Hobie is told that a ranger named Hobie Gilman has already picked up the prisoner, and the unsympathetic sheriff tells a cash-strapped and badgeless Hobie to get out of town.
Steve McQueen plays a dual role, and he's much better in this episode than he was in "The Bounty Hunter" earlier in the season. Even though McQueen is playing both Mal and Wes, they're clearly distinguishable from each other in personality, and not just in the dialogue they're spouting.
But Richard Devon, who generally played ruthless outlaws or backstabbing criminal accomplices (e.g., Machine Gun Kelly, The Twilight Zone episode "Dead Man's Shoes") is what raises this episode above other '50s westerns with twin brothers being mistaken for each other. His nonchalance meshes well with Gilman's usual nonchalance, and his dialogue with Gilman paints as complete a portrait of the town as a gaggle of citizens or narration (as with "The Town" earlier in Season 1, absent from this episode) ever could. This and Devon's recurring role as Jody in Yancy Derringer make me wish Devon had had more varied roles during his career.
There are definitely more layers to this episode than the usual "I don't know which brother is which" turn this type of plot line usually took in '50s TV westerns, and Richard Devon as Fenn is a highlight.