Salter said. And tunnels, he added, need not be so expensive to dig is people think. The most expensive thing about surface routes is the acquiring right-of-way and removing buildings that stand on the chosen route. The tunnel would not incur this expense. The tunnel, besides carrying tubes for passenger and freight gondolas, would carry many of the utilities now strung across the countryside on high wires. Salter said these underground power "lines" could be super-cooled with helium, like the electromagnetic loops in the floors of the gondolas. He said this would so reduce resistance that power could be transferred from one end of the country to the other with