This story starts in Sandusky, Ohio, in 1821. How do we get from Ohio in 1821 to this old railroad bridge in 2009? Well, we start by going to Philadelphia. Financier Jay Cooke was born in Sandusky, Ohio, on August 10, 1821. Cooke's father was a prominent attorney and a Congressman. Cooke used this wealth and connections to successfully build a fortune as the Jay Cooke and Company. Cooke founded a private bank in Philadelphia in 1861. When the Civil War broke out, he arranged financing for many war projects, including a large loan for the state of Pennsylvania.

As the Civil War progressed, Cooke became interested in railroads. Cooke established the Lake Superior & Duluth Railroad in 1863. While construction was slow during the war, the rail line was completed between Carlton and Duluth in 1870. The original line ran through Thomson, along the north and east side of the Saint Louis River, through Fond du Lac, and into the west end of Duluth.

Cooke became fascinated with Duluth. He had a vision that a northern railroad would connect Duluth to the Pacific Ocean, allowing cargo to connect through the Great Lakes to European markets. He saw Duluth as being the next great American city. He was so sure of this vision that he bet his fortune on the Northern Pacific Railway. Unfortunately, Cooke was caught short during the Panic of 1873, and he ended up bankrupt.

The Lake Superior & Duluth Railroad became the Saint Paul & Duluth Railroad in 1877, eventually connecting the Twin Cities to the Twin Ports via Hinkley. The Northern Pacific Railway purchased the Saint Paul & Duluth Railroad in 1900. The steep grade between Thomson and Fond du Lac was increasingly impractical, so the Northern Pacific Railway rebuilt the line between Carlton and Duluth a little further north and east, coming down the bluffs between the current day Spirit Mountain Ski Hill and the Lake Superior Zoo. This 1906 project coincided with the construction of the Thomson Dam. The new route ran east and west through Thomson just south of present day MN-210 and Thomson Road. The rail line crossed the Saint Louis River about 1,200 feet south of the Thomson Dam using a 150-foot long steel truss bridge.

Known as the ‘Skally Line’, the Northern Pacific Railway mainline between Saint Paul and Duluth was an important rail connection. It featured passenger traffic until 1930. The line did suffer from competition given the large number of railroad links between the Twin Cities and the Twin Ports. In fact, at one time, there were 11 different railroads with passenger depots in Duluth. Traffic declined after World War II. This forced the Great Northern and Northern Pacific to merge, which they did with the Chicago, Burlington, and Quincy in 1970 to form the Burlington Northern. The BN had two lines running from the Twin Cities to Duluth that were almost parallel for much of that distance, so the Northern Pacific route was abandoned in the 1970s. The right-of-way between Hinkley and Duluth became the Willard Munger State Trail.

What happened to Jay Cooke? He had repaid his debts by 1880. He invested in a silver mine in Utah, which struck it big. Cooke again became very wealthy. Some people simply have the golden touch. Cooke's legacy here in Minnesota is the Jay Cooke State Park. Cooke was an avid outdoor sportsman who lobbied for the creation of national parks. It is fitting that Cooke is honored by having his name attached to the crown jewel of the Minnesota state park system.

The photo above is looking downstream to the south towards the Willard Munger Trail Bridge over the Saint Louis River. The vantage point is along a difficult trail over the rocks along the east bank of the river heading south from the University of Minnesota Duluth Outpost parking lot and passing under the highway MN-210 bridge. While the trail is a challenge, the views are worth the effort.

These two photos are views of the north side of the truss structure as seen from the edge of the cliffs at each end of the bridge. The photo below is looking west from the east side of the river, while the photo below is looking east from the west side of the river. The trees make it impossible to see the entire bridge from these vantage points, and the cliffs make it dangerous to attempt any more adventurous shots.

These two photos are views looking down the bridge deck through the bridge truss structure. The photo above is west down the center of the bridge, while the photo below is looking east from the west end of the bridge.

The photo above is looking west down the Willard Munger Trail from midspan of the truss structure. The wooden deck and railings were added as part of the conversion from railroad to state trail. The photo below is a closer view of one of the observation bump-outs on the bridge deck.

The photo above is looking upstream to the north from the bridge deck. The river falls 449 feet between the outflow of the Thomson Dam and Lake Superior, creating a spectacular series of cascades along the way. One can see the high water marks on the rocks showing where river levels were prior to much of the Saint Louis River being diverted into the Forbay Canal and the Thomson Energy Project power house. The photo below is looking downstream from the bridge deck into the bright mid-day sun.

The photo above is the bridge abutment at the east end of the work. The stonework dates this bridge to a pre-WWII structure. Concrete would have been used increasingly throughout the 1920s and 1930s. The photo below is a view of stonework and drainage at the north west corner of the structure. Trees growing out of the stonework is not good for the long term health of the structure since it can move the stones and collapse the wall.

These two photos are details of the steel construction of the bridge truss. This is a pin-connected bridge, meaning that welds and gusset plates were not used to join the beams. Rather, the beams are held in place by steel pins and tie bars. These two photos are examples of two pin connections, the photo above near the west end of the bridge, and the photo below at the center of the bridge span.

The photo above is an example of a steel beam in the trusswork above the bridge deck. This style of using crisscross tab joining two paralleled U-channel members is a classic feature of bridge built around 1900. Steel was expensive and labor was cheap, so it made for an ideal solution. The photo below is a pin connection at the northwest corner of the bridge. The rivets are used to attach plate-doublers to the steel, increasing the strength of the beam where the pin goes through the beam. The large nut on the end of the pin keeps the pin from sliding sideways out of the hole as the bridge flexes during heat and cool cycles each day.

The photo above is a sign warning visitors to beware of the river currents, which have trapped and drowned a number of people over the years. The photo below is the bridge plate.

A flash flood of historic proportions hit the Duluth area in June, 2012, resulting in serious damage to the Thomson Hydro Project. As a result, the entire flow of the Saint Louis River was diverted down the old river channel under the Munger Trail Bridge. These views are looking south towards the upstream side of the structure in the summer of 2013. The photo above is looking downstream from an overlook on the east bank of the Saint Louis River. The photo below is taken from the west side of the river just upstream of the bridge.

The Munger Trail was heavily damaged in the 2012 flood. There were washouts, culvert failures, landslides, and places were the pavement was lifted and moved by the water. Once the landslides were stabilized and the washouts filled, the trail had to be regraded and paved. At the same time, the deck and rails were replaced on the Munger Trail Bridge. The photo above is the east end of the structure, while the photo below is the west portal.

The photo above is the new bridge deck that was installed in 2013. The photo below shows the new railing, which is much sturdier than the railing that it replaced.

The photo above is a detail view of one of the bridge columns. I am fascinated at how much work must have gone into building these columns in this manner with the uncountable number of tabs and rivets that went into each frame member. This must have been built in an era when labor was cheaper than materials. The photo below is the steelwork at the top of the west bridge portal.

While I was under the bridge to get a photo of the river as it heads downstream beyond the bridge, I decided to get a few shots of the pin connections. Pin connected bridges were commonly built between 1885 and 1915. They had the benefit of using less material compared to fixed connections, and they could be erected very quickly (a matter of days once the falsework was in place). They have two key disadvantages in that the pin becomes a key failure point and that the pins are impossible to inspect. These two photos are views of two different pin connections on the upstream side of the structure.