Milepost 9.1: Approaching Keystone. The old Chicago, Burlington & Quincy Branch line between Hill City, SD and Keystone features a number of timber trestles, many of which can be seen from Old Hill City Road. This one is at Milepost 9.1, less than a mile from the station at Keystone and just before the last of the 14 grade crossings that the line makes. Like many spots on this line, this one has light for most of the day. Here, we see Locomotive #110 with the second trip of the day, drifting downgrade and blowing for the crossing. Interestingly, with less than a mile to go, this train still has two more timber trestles to cross before it reaches Keystone.