Golden Spike Cultural Landscape Report

Natural Features and Systems

The alignments of the Union Pacific and Central Pacific grades were determined in part by the physiographic character of the area. The level pass at Promontory Summit attracted railroad surveyors as a way through the Promontory Mountains. However, although the summit basin produced few engineering obstacles, the slopes of the mountains on either side, particularly those on the east slope, did challenge the UP and CP engineers. Numerous cuts had to be blasted through the rocky terrain and the deep ravines had to be either filled or bridged with trestles.

The steep terrain required that the grade follow the contour of the hill slopes, necessitating the use of numerous sharp curves rather than straight tangents.

As authorized by the 1862 Pacific Railroad Act, the railroad's construction crews made use of any and all available natural materials found within the landscape along the route of the road. Local stone sources were quarried for material to build culverts. The rock rubble blasted from the grade cuts was used at other locations along the line as base course fill, while gravel deposits were excavated for use as ballast along the completed grade. Numerous borrow pits were excavated to provide much needed soil for the extensive fill areas along the route. Water was not readily available, so it was hauled to the construction areas and camps by tank cars and wagons.

The construction crews made use of the landscape's natural features for the siting of their campsites. In some areas hills and rock outcrops were used to shelter campsites from the prevailing winds. A few naturally occurring rock shelters were used as campsites. Locally gathered rocks were used to create low masonry walls for simple dugout structures or for outlining tent platforms. Ranch families who settled in the area tell of gathering the locally available sagebrush for use as fuel, so it is likely that the construction crews did the same.

Certainly, the workers in their temporary campsites used locally occurring materials to construct shelters for themselves. Photographic images of graders' campsites show men in front of small, sod-covered shelters (Figure 41). Some appear to have been built with the rear of the shelter formed by a hill slope.

Figure 41. Photograph of unidentified railroad construction camp snowing individual sod-covered shelters. Source: Unknown photographer and unknown date, negative #F-14094, on file at the Colorado Historical Society, Denver, CO.

Summary

The natural systems and features of the Promontory Mountains had a great influence on the construction of this segment of the transcontinental railroad — influence felt at a variety of levels. At the largest scale, this influence is still apparent — manifest in the location of the grade in relationship to the natural topography of the area. At a smaller scale, the influence of natural features is seen in the use of naturally occurring rock shelters as worker's campsites.

Contributing landscape features include the level basin in the summit area, the steep, dissected hill slopes on the west and east sides of the summit, and the natural rock shelters used as campsites by railroad construction workers.