The wood-line. Of the three major types of fuel used by steam locomotives, wood is probably the most time-consuming to load. Unlike coal and oil, which can be poured into a tender from dedicated facilities, wood pretty much has to be loaded and stacked by hand. With all of the locomotives at Clark's burning wood, the folks here are very much used to the drill. Here, at the end of a service day, the crew forms a wood-line, with one member picking the logs and the remaining ones passing them up into the locomotive cab to the Engineer/Fireman, who carefully stacks them for the most efficient use of available space. Another disadvantage of wood is that it does not have the BTU value of coal or oil. Wood-burning locomotives go through their fuel supply very quickly, meaning the operation you see here has to be repeated fairly often. Fortunately, for the folks at Clark's, this isn't a big deal, because the entire railroad is only a mile and half long, so they refuel perhaps once a day.