Rocket Propellant

Men and women were hurrying back and forth, up and down the streets and walk paths, but no one stepped into the corridors. I said: "With the exception of police and other emergency cars, all transportation in Bos-Wash is accomplished by public vehicle." "But where are they? I don't see them." "That's because they're not there… now." It was clear that she didn't understand. "For a long time," I explained, "we've been faced with the problem of safe transportation. In the past vehicles have run into each other, hit stationary objects, and have even collided with pedestrians. Well, we've finally come up with what we believe is a reasonable solution. Those corridors you see are depots for our tube cars. Tube cars are rocket propelled vehicles which criss-cross back and forth across the city, racing through time tunnels…" "Time tunnels?" "Holes punched through time," I explained. "The vehicles travel across this same space, but in a different time period. In a time period when there weren't any vehicles, or people for that matter, to obstruct their course ...»