“I think the way we are looking at this is we are really interested in the [Pittsburgh-Columbus-Chicago] corridor and this is a really interesting concept,” said William Murdock, executive director of the Mid-Ohio Regional Planning Commission. “We thought it was worth pursuing.”  The proposal for a hyperloop, called Midwest Connect, is simply an idea at this point, Mr. Murdock said. With the selection as a semifinalist, the agency will begin the serious detail work with the other cities to determine the cost, exact path of the hyperloop, where stations might be located and how public-private partnerships might help pay for it.