The Kansas City Streetcar Authority Inc. unveiled potential alignments for the planned Main Street extension on Tuesday. Kansas Citians weighed in on the 3.5-mile line south to the University of Missouri-Kansas City's Volker Campus at an open house meeting. "We're wanting this to be the spine of the transit service," said Chuck Ferguson, chief planning officer for the Kansas City Area Transportation Authority. Because the route is more transit-focused than the streetcar's starter route, the stops…