Line 9
Boarded the train there's no getting off.
This line, which is enjambed with the previous line, seems to imply that boarding the train is either along the same thought-line, or as a result of eating the bag of green apples.
This line shows us that our speaker knows that, so to speak, once she's gotten pregnant, she's boarded a train that she can't get off of—her life is forever changed and there's no going back.
For other women, who perhaps choose another path (abortion), or have it thrust upon them (miscarriage), there's a chance things may change, but this woman knows that she is stuck with this baby, this life as a mother, for good.
This train stretches for at least nine months, and, if the baby is not given up for adoption, for the rest of the mother's life.