A couple of months ago, I shared a couple of photos of the unique multiple-arch engineered dam design, and mentioned that the prevailing type of dam has always been the massive gravity dam, where the shear weight of the structure is what holds the water back. Typically, such dams are made of many, many tons of rock and earth piled up.
Today's photo shows just how this used to be done, although the location is unknown. A railroad bridge is built across the middle of where the dam is to stand, and train after train of cars hauling the fill dump off to the side, where the rock and earth are spread out by teams of horses pulling rakes. As thousands of trainloads are dumped, the mound is built higher, burying the trestle.