Regularising rolling stock and rail gauge would pay back in many ways, I realize it's the kind of <groan> moment, but being behind a 60 day troop/materiel movement delay because of 10cm of steel is painful.<p>We've done this before. It's slow. The best time to be on 4ft 8-and-a-half inches is 194 years ago. The second best time is to start now.<p>(Stephenson opened the liverpool to manchester line on this gauge in 1830)