Black Hills Central #110. Keystone, SD. James Willmus, 2012 The Chicago Burlington and Quincy Railroad built a rail line through the heart of the Black Hills known as the "High Line". The branch, which would one day become the George S Mickelson Trail had steep grades and sharp curves, but at the turn of the Twentieth Century there was a need to haul freight on the line to and from Deadwood. Large, solid frame engines couldn't make the turns and big drivers wouldn't do well on the grades, so a new engine was needed for the fleet. Fortunately, other railroads had the solution, articulated locomotives. Instead of one long set of driving wheels, the drivers were divided into two sets of bogies with their own separate valve systems. The most common arrangement of articulated locomotives was the compound mallet. This type of engine used the steam twice with high-pressure cylinders in the back and low pressure cylinders in the front. While traveling between the dri