Stonearch

St. Paul, Minneapolis, and Manitoba Railway “Stone Arch Bridge” (1883-present)

Engineering for this bridge type

Perhaps the most graceful symbol of the importance of the Falls to the history of Minneapolis is the Stone Arch Bridge. Completed in 1883 for James J. Hill's St. Paul, Minneapolis, and Manitoba Railway (later the Great Northern Railroad Company), the bridge sweeps over the water and curves up the river, just above the Falls. Construction of the bridge cost $650,000, an amazing sum for its day. Hill, a major entrepreneur and “captain of industry,” and his partners built the bridge to connect their railway system to the new Union Depot planned for the intersection of Hennepin and Nicollet avenues. Hill originally planned to build a shorter, cheaper bridge above St. Anthony Falls but was advised by Charles Smith, his chief engineer, that such construction could result in the collapse of the Falls, already rendered unstable by the Eastman Tunnel disaster of 1869, and thus the loss of its waterpower resources. Smith recommended that the east bank bridgehead be located below the Falls. This, along with land owership complications, required that the bridge be aligned in the sweeping curve which gives it such visual drama, with the upstream section running parallel to the river to create a straight entry to the Union Depot. Most engineers at the time were dubious that a masonry bridge with such a curve would have the strength required to withstand the weight and vibrations of the trains. However, the final design, built of locally-quarried Platteville limestone, St. Cloud granite, and magnesium limestone from Stone City, Iowa, has proved to be strong and durable.

The 2,100-foot-long bridge was originally comprised of twenty-three limestone arches, each spanning between 40 and 100 feet and supported by granite piers and abutments. At its western end, at the approach to the Union Depot, the tracks crossed the open water of the milling canal “headrace” (intake) pool on a truss structure. When the Upper St. Anthony Lock was constructed in the early 1960s to facilitate upstream navigation, two stone arches and one pier in the vicinity of the lock channel were removed and replaced with a steel truss. In 1975, the bridge was designated a National Historic Civil Engineering Landmark.

Like other businesses that helped build the Twin Cities, rail transportation declined throughout the twentieth century. The last train crossed the Stone Arch Bridge in 1978, and the tracks were removed in the early 1980s. But this unique structure---the only arched bridge made of stone along the entire length of the Mississippi River---is a great physical reminder of all the hustle and bustle that once went on at the Falls. In 1994 the Stone Arch Bridge was re-opened as a pedestrian and biking bridge. From the middle of the bridge, a viewer can see the expanse of the Falls and imagine what it must have been like in the days when it was crowded with flour and lumber mills, and filled with people.