The Emmett Water Clock.
Well, I suppose it made up for the destruction of Nottingham Victoria Station - four through platforms and four bay platforms at each end on two islands. Six platforms in each direction constrained into two track tunnels. A huge cavern containing a great railway station. I remember the spot where I stood and watched my father being taken back to his minesweeper when I was about three.
It was on the Great Central Line - built to continental loading gauge with a view to linking it to continental rail services by means of a Channel tunnel. And linking Manchester, Sheffield, Nottingham and Leicester with ... eventually ... Wembley Stadium.