Water at Hill City. Shortly before departing for on the first trip of the day, Black Hills Central Locomotive #108 pauses at the wooden water tower in the yard at Hill City, SD. Unlike most steam locomotives, which take on water in a tender, the saddle-tankers on this railroad require a bit of climb on the part of the fireman, to add water to the massive, blue tank which sits over the boiler. While that tank technically holds enough water for the entire round trip to Keystone, the locomotives typically take on some additional water from a much smaller water tower on the other end of the line, just for safety. Keeping that tank full has other advantages. Being centered over the two sets of drivers, that saddle tank, when full, gives this engine a better grip on the rails, enabling it to tackle grades not seen by rod engines on any other tourist railroad in the US.