Toppin' Tin Mill Hill. After struggling on the 4-6% grades for about 8 minutes, the Black Hills Central Railroad's 9AM train for Keystone SD, reaches the top of Tin Mill Hill, emerging from a rock cut, just prior to crossing Old Hill City Road for the 3rd of what will be 14 times in the next hour. The locomotive is barking pretty loudly here, and this is one of the few places where you will see her make smoke. On the point this morning is Locomotive #110, a Baldwin 2-6-6-2T, built for the Weyerhauser Timber Company in 1928. Although she's a brute of a locomotive, she's often on her knees on this hill with a 7-car passenger train. Fortunately, just barely a mile into the journey, the bulk of the heavy lifting is done, at least for the eastbound run. There's just one more grade to go, before it's all downhill to Keystone.