The format to follow is similar to a book chapter citation, for example, a poem from the edited collection, Seven Centuries of Poetry in English would look like this:
First footnote:
3. Seamus Heaney, "The Railway Children," Seven Centuries of Poetry in English, ed. John Leonard, 5th ed (South Melbourne: Oxford University Press, 2003), lines 7-8.
Subsequent footnotes:
5. Heaney, "The Railway Children," 11.
Note: you can omit "line" or "lines" from the shortened footnote as long as the numbering you're using has been explained in the first footnote.
Bibliography:
Heaney, Seamus. "The Railway Children." Seven Centuries of Poetry in English, edited by John Leonard. 5th ed. South Melbourne: Oxford University Press, 2003.
Further examples can be found in the complete Chicago Manual of Style - see links below.
