I loved Railsea too, especially the concept of Mocker-Jack as a "Philosophy" and the comparisons of the rails to the symbol "&". That embodiment of linguistic concepts like the infinite deferral of meaning links Railsea to Embassytown in my mind. Mieville makes my theorist heart go pit-a-pat!

Also, I hadn't even heard of Dial H, but looking it up, I will have to check it out. Thanks for the mention!