Sham Yes ap Soorap is a young assistant doctor on a moletrain, captained by Abacat Naphi, that hunts giant moles for meat in a similar fashion to whaling.

They rescue them from their now almost incapacitated train and with a navy wartrain in close pursuit, venture out onto the lonely rail leaving the sea behind them.

The moletrain crew decide to return with their valuable salvage to the known world, whilst Sham and the Shroakes press on by foot to see what lies beyond.

[4] Stephanie Burt remarked on Miéville's inventive language and world-building, and noted that the author's far-left politics are reflected in the slowly emerging history of Railsea's derelict world, which amounts to a "funny, far-reaching indictment of modern capitalism".

Writing for io9, Chris Hsiang noted that it abounds with "impish literary games", and praised its avoidance of either "dystopian romance tropes" or political sermonising in favour of a challenging, weird but still approachable language and structure.

Club wrote that while Miéville's swift and absorbing (if dense) prose and lean plot yielded a "brainy and thrilling" result, it would have been improved "if only he'd stopped less to comment on his own cleverness along the way".