#6 The Big Fill and the Big Trestle

The Big Fill and the Big Trestle

NPS/ncastoro

As late as December 1868, Central Pacific surveyors planned a route that would have required blasting an 800-foot tunnel through the east face of the Promontory Mountains. During an inspection of the site, Central Pacific President Leland Stanford overruled the idea as too costly and time-consuming. Surveyors selected a new route that avoided tunneling but posed a new challenge: how to cross Spring Creek Ravine.

In February 1869, the construction firm of Benson, Farr, and West—whose members were part of the Latter-day Saints—began work on the Central Pacific’s Big Fill to span the ravine. Imagine placing the first small, mule-drawn dump-cart load of fill at the bottom of the ravine below you. The work that followed required more than two months of intense effort by 250 dump-cart teams and over 500 workers. Load after load of fill, totaling more than 101,000 cubic yards, was needed to conquer the 500-foot chasm. The Big Fill remains one of the most impressive construction efforts in the history of American railroading.

To span Spring Creek Ravine, the Union Pacific constructed the Big Trestle, located 150 feet east of the Big Fill. Because it was intended as a temporary structure, construction of the Big Trestle took only 36 days, compared to the Central Pacific’s Big Fill, which required more than two months.

The trestle stood 85 feet high and stretched 400 feet long. As one reporter observed, there were no words that “…would convey an idea of the flimsy character of that structure.” Another reporter suggested that it “…will shake the nerves of the stoutest hearts of railroad travelers when they see what a few feet of round timbers and seven-inch spikes are expected to uphold—a train in motion.”

Within the year following completion of the transcontinental railroad, the Central Pacific gained control of the route from Promontory Summit to Ogden, Utah, and trains began using the Big Fill rather than the Big Trestle. Ogden soon replaced Promontory Station as the primary terminus for both railroads, and track was removed from the trestle. Today, only photographs, abutments, and footings remain to remind us of the Big Trestle.