The record starts with the groove already complete — a churning guitar riff over light drums on a single chord. There is no build and no introduction; the pattern that will carry the whole track arrives at once, and the only thing withheld is the voice.

The voice enters at 0:10 with the title line, ah-oh, smokestack lightnin', two sung lines answered by the whoo-hoo moan that will end every verse. A second cycle at 0:37 — tell me baby, what's the matter with you — repeats the shape exactly: short questions, wail, drop back to the chug. By 1:00 the form is fixed; each verse is a brief vocal island inside one continuous instrumental run.

The only role change in the track. The singing stops and a harmonica moves to the front for about fifteen seconds, bending over the unchanged chug. Formally this is the bridge — not a break in the groove, only a swap of lead voice.

Three more verses keep the same schedule: where did ya stay last night at 1:14, stop your train at 1:36, fare ya well at 2:06. The form does not change; the lyric does the moving, from accusation to pleading to farewell. Instrumental gaps between verses stretch longer here, so the repetition itself becomes the content.

The last verse — who been here baby since I been gone — lands at 2:31 and closes with girl, be on and a final whoo near 2:44. The chug carries on briefly, then eases: the motion thins through 2:51–2:59 and the last chord rings out into silence by 3:06. No cadence and no return of the refrain — the track ends by stepping off the groove it never left.