The Dick's Sporting Goods Pittsburgh Marathon is set to begin in less than 36 hours, uniting tens of thousands of runners and spectators for Pittsburgh's premier running event."Chronicle: The Runners of Pittsburgh" -- Watch the full episode in the video player aboveThe event, which includes a record estimated 45,000 participants, features stories of runners who have trained intensely for months.Many young runners started their journey with the Kids of Steel program and now are participating in the half-marathon. Pittsburgh's Action News 4 anchors Mike Clark and Kristen Powers will be live on Friday from the Pittsburgh Live Well Expo, presented by GNC, where runners will be preparing for Sunday's big event. Looking for information on the Pittsburgh Marathon? We have a handy guide to help you track a bib, find road closures and even see the finish line.