BONUS SONNET: In Which I Muse On A Strange Literary Trope

A city that's a giant railway train
Seems to me a most strange motif to keep
Encountering in fiction, e'en the strain
Called speculative. And there's a small heap
Of books I've lately read that featured such:
The characters must build the way before
Then tear up rails and ties behind. A crutch
For storytelling? I think maybe more
Is going on than that in these great books:
Mieville's Iron Council, Reynold's Gap,
And Christopher Priest's Inverted World looks
To do it, too. Allusion to the trap
Of civilized life is what I most see,
But still most strange this trope appears to me.