Can anyone fill in these blanks?:

Peanut something something
Sitting in the gutter
Along came something;
Oops! Peanut butter!

The closest I could find was this:

Peanut sitting on a railway track
Heart all a flutter,
Around the corner comes the train,
Whoo, Whoo, peanut butter

Must be plenty of slightly different versions among small schoolchildren. I remember hearing (when my experience of life still hadn't included peanut butter. so I didn't 'get' line 4) the following one:

A peanut lay on a railway track.
His heart was all aflutter.
Along the railway came a train.
Toot, toot, peanut butter.

Thanks to you both. I guess it wasn't the gutter (and my residual visual of a Cadillac coming 'round the bend) after all, but exactly like the apple:

Apple on the railroad track,
Feeling mean and cross,
Along came the 5:15,
Whoops! Applesauce!