A national recreational trail advocacy group has launched a petition to have the $2.5 billion Miami-to-Orlando passenger rail corridor include a pathway for walking and biking. The Washington, D.C.-based Rails-to-Trails Conservancy has collected more than 800 of the 10,000 required signatures needed to petition Coral Gables-based passenger rail developer All Aboard Florida and the Federal Railroad Administration to include a walking/biking trail alongside the train system. The group has matched…