What she means is that she had made 19 trips to Maryland, helped 300 people to freedom, yet she was never captured and didn’t fail to deliver her "passengers" to safety. As Tubman herself said, "On my Underground Railroad I [never] run my train off [the] track [and] I never [lost] a passenger." During these journeys she helped rescue people that were from her own family and people who weren’t from her own family. You can check her story in the America Library.
Answer: all of the moods
Explanation: There is no right answer to this. Different people have different reactions to this poem but, I'm going to go with a mysterious, secretive mood.