This fireman is shown, in a posed 1905 photo, stoking the firebox of a small switching locomotive. His scoop is laden with a great deal of coal - far more than most firemen would take in a single shovelful.
It was important to fire "light and often," meaning that the most successful technique was a light load of coal on each scoopful, and to direct that light load to a precise spot on the firebed (the bed of burning coals on the firebox grate).
The fireman never hit two shots of coal to the same spot successively, but spaced out the shots, so as to keep the firebed level and even, with no 'holes' (burned out spots) and no overly thick areas, which starved the burning coals for air and created excessive smoke.
Note the style of hat with stiff bill, which predates the supposedly traditional, narrow-striped, soft denim work cap that most people identify with railroaders. The style shown in this photo was common from the 1880s until the early 1930s, overlapping the advent of the denim cap. (The style shown was chosen for the engineer and fireman figures on display inside Southern Railway locomotive 1401's cab in "America On The Move.")