The Underground Railroad situates itself in the province of memory, rather than history as such. Whitehead borrows from multiple eras and aspects of the African American "experience," drawing on the Tuskegee study and Jim Crow just as much as slavery. The railroad--both as link between and tree branches of--literalizes the slippage between atrocities and keeps them distinct from one another even as the episodic nature of the text piles them up. While not all of the events could have happened to Cora--any more than the train is real--Whitehead's book is more concerned with the book as a record of lived experiences. It is, for lack of a better term, a guidebook. But it's also a story of how historical events become personalized. It's a book that tries to tell a truth, rather than a history. I think, for all its discomfort and confusion, it succeeds.