David points out a neat Chinese scheme to reduce traffic congestion while increasing public transport. A massive bus that travels over the traffic - it may make a lot of sense. I could certainly see these in Manhattan.
a tip of the hat to David.
Greg adds this historical note:
Called the “Leap Frog” railway, here is a bit of info here
“Dreamland’s Leap Frog Railroad, built out on a special 400 foot long pier jutting into the sea, was a one track railroad that went nowhere. It was built to meet an absurd challenge once posed by Mark Twain; “the only thing Yankee ingenuity had not accomplished…the successful passing of two carloads on a single line of tracks.”
Each of the Leap Frog cars were equipped with a pair of bent rails on their roofs that allowed the approaching cars to glide over or underneath each other. The 32 frightened passengers bracing for a collision, were relieved when the other car safely passed overhead. On the return trip the cars changed positions so that passengers on both cars got to experience the sensation.”