'The West Midland Underground goes from to . Or should I say went? Should I have said went? Should I be saying went? Or even will go. May go. Could go. Could have gone. Was to have gone. Is to go. Is to have gone. Is it possible to say is to have gone? Are there certain tenses that do not exist, may not, cannot, will not, did not; though now do? Perhaps the impossible tenses are needed for the impossible underground. Perhaps the hitherto impossible tense will bring into being the hitherto impossible West Midland Underground.' (Introduction)