Q: Context: "Big Iron" is a country ballad written and performed by Marty Robbins, originally released as an album track on Gunfighter Ballads and Trail Songs in September 1959, then as a single in February 1960 with the song "Saddle Tramp" as the B-side single. Members of the Western Writers of America chose it as one of the Top 100 Western songs of all time.

Question: who sings the song big iron on his hip?
Let's give stream of consciousness below
The relevant information to answer the above question is: "Big Iron" is a country ballad written and performed by Marty Robbins, originally released as an album track on Gunfighter Ballads and Trail Songs in September 1959, then as a single in February 1960 with the song "Saddle Tramp" as the B-side single. So the answer is Marty Robbins.