Here is a page from the Bulletin No. 15 from Roberts and Schaefer Co. of Chicago. It dates from around 1912.

Coaling stations/towers were designed to fuel steam locomotives.  They came in all sizes and shapes.  Some were behemoth structures, while others consisted of a pile of coal, and a power shovel along a sidetrack. In the 19th and early 20th century, coaling stations were an integral part of every railroad. There were numerous coal stations; most towns with locally based locomotives had some type of coal facility.  There were also coaling stations located at intervals along routes, so that locomotives of through trains could fill up quickly, and maintain their schedules. Some were combined with water and sand holding structures. The introduction of diesel locomotives, led to the replacement or abandonment of these structures, and the use of  smaller overhead tanks holding diesel fuel.