This route crosses two passes on the Continental Divide and is full of history and interesting sites. The route follows the grade of the Denver South Park and Pacific Railway beginning at the ghost town of St. Elmo. The railroad grade has been converted to a county road until it reaches the ghost town of Hancock, where the route turns to a trail with a very gentle grade leading to the east portal. At the east portal (closed tunnel entrance) it's necessary to ride (sometimes it's a three point carry the bike) over Altman Pass to the west portal of the tunnel on the on the Pacific side of the Continental Divide. There is a remaining turntable for the engines and some other railroad structures at the west portal. Returning over Altman Pass on the same path, the route then climbs Williams Pass, the second crossing of the Continental Divide). It's a fast ride back down to the mouth of Chalk Creek after reaching the second climb of the day.