Looming out of the fog on an utterly still and silent February morning, this abandoned railroad bridge in Tazewell county stands as a forgotten relic of a bygone era. Located between Green Valley and South Pekin, IL, it is a 100 foot steel Pratt truss bridge that spans the Mackinaw river.
This bridge has an interesting history which is reflected in its unique appearance. It was constructed by the St. Louis, Peoria & Northern Railroad in 1897. That line was something of an upstart and part of an ambitious plan by a would-be railroad mogul to create a shorter and faster “air line” freight route between St. Louis and cities in northern Illinois. Its construction was seen as a threat to existing north-south rail lines, and none more so than the Chicago & Alton. There is far more to this story (which will be covered in future posts about this line) but in 1900, the C&A bought the Springfield-Pekin portion of this line in foreclosure and quickly incorporated it into its own network. In the line's early days it was primarily used as a freight route to haul coal from southern Illinois into Peoria (and beyond via connections with other roads).
Hauling such a heavy commodity over this line was not a difficult matter for the majority of its length, but there was one exception - the grade from the north side of this bridge to the top of the bluff. Known as “The Mackinaw Hill”, it was a notoriously steep grade that frequently caused freight trains to stall. When E.H. Harriman had wrested control of the Chicago & Alton away from Timothy Blackstone in 1899, it was an outdated road much in need of new equipment and infrastructure improvements. This change in management brought an influx of capital, and in 1900 the C&A engineering department set out on a multi-year plan to replace bridges, eliminate curves, and reduce grades throughout its entire network.
As part of that series of improvements, it was deemed that the Mackinaw Hill grade needed to be reduced to 0.3% in order for C&A 300 class locomotives (2-6-0 Moguls) to be able to pull the intended per-train tonnage up the hill without helper engines. This would be accomplished in two ways. One was to significantly deepen and extend the cut from the bottom of the river valley through the top of the northern bluff, and the other was to raise the truss span of this bridge by a height of 12 feet.
When the bridge had been constructed a few years before, the shoes of the truss had been placed directly on top of the poured concrete piers. Raising it up 12 feet from that position would be no trivial matter under any circumstance, but to complicate the situation, it was decided that the line was too vital to be closed during the project. This meant that the bridge would need to be raised just inches at a time over the course of several months while regularly scheduled trains still ran over it.
Work began in September of 1905 with two crews working in tandem, one extending the cut into the northern bluff and the other raising the bridge. The bridge raising was accomplished by using hydraulic jacks to lift the truss shoes off of the piers 3-4 inches at a time and placing short concrete blocks beneath them. The truss would then be set back down on the blocks, and the approaching rails adjusted to match the new height. Each time the bridge was raised to a new height of 18 additional inches, permanent concrete slab blocks (which were cast onsite) were placed under the truss shoes. This slow incremental process was repeated for the next several months until the blocks were stacked eight layers high, and their presence today is what gives this bridge’s piers such a unique look.
After the raising of the truss span was complete, new timber pile trestle spans were constructed on both the north (550’) and south (605’) approaches. Jagged remnants of the 1905 northern approach trestle can still be seen jutting up from the water at the river’s edge.
With the completion of the grade reduction in the spring of 1906, freight traffic boomed on the Peoria & Northern division (as this line was called) throughout the early 1900s. Declining demand for coal and competition from trucks for freight traffic took its toll on many branch lines throughout the mid 20th century, and this line was no exception. The C&A was merged into the Gulf, Mobile & Ohio in 1947 which later merged with the Illinois Central Railroad in 1972. As this line had been primarily used as GM&O’s freight route into Peoria, the merger with the IC made it redundant, and the last train to cross this bridge did so in 1979. It was abandoned that same year and the rails and ties were removed shortly thereafter.
Significant remnants of a mid-century replacement of the northern approach trestle still remain, but the southern trestle has been completely removed. The steel truss still sits atop the concrete blocks and piers, though. Abandoned now for nearly 50 years, it is seen only by farmers working the surrounding land and occasional recreational boaters floating along the Mackinaw river.
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