To interrupt the utility of bridges, tunnels, highways, railroads, Switzerland has established three thousand points of demolition. That is the number officially printed. It has been suggested to me that to approximate a true figure a reader ought to multiply by two. Where a highway bridge crosses a railroad, a segment of the bridge is programmed to drop on the railroad. Primacord fuses are built into the bridge. Hidden artillery is in place on either side, set to prevent the enemy from clearing or repairing the damage.