Admittedly, I read this for its relationship to Moby-Dick. The novel certainly does capture what I consider central to MD: not the whale hunt that drives its plot, but rather the exploration of epistemologies--Ahab/Naphi's vengeful philosophizing (in a brilliant turn, Captain Naphi reveals that her amputation is a construction that follows, rather that precedes her hunting Mocker-Jack) v. Ishmael/Sham's quest for meaning. Where Ishmael concludes that the whale must remain unpainted to the last, Sham seeks to(as a less sinister Ahabian) map the world to the edge of what is known and beyond it.

Outside this association (and it's certainly not necessary to have read Moby-Dick to enjoy Railsea), it's a wonderfully fun story. It's especially great to see post-modern literary quirks trickle down to YA lit in a way that is accessible to a younger audience.