Sunday, July 9, 2017

Old Up-and-Over Wood Bridges

John Carson shared four photos with the comment:
ANOTHER AGING SURVIVOR: From the CB&Q RR, a CB&Q style road overpass bridge. This survivor is just north of Vermont Illinois. There were many of this style of bridges carry roads and streets over the CB&Q back in the day. We still have a few survivors in this area, but they are gradually being removed or replaced. These all have posted weight limits per axles, which max at 28 tons. Enjoy!
Steve R Hampton I loved taking this bridge at 60! We'd fly for yards! !

A comment confirmed it was the Heitz Road overpass.




I have already described the Oak Street Bridge in Hinsdale.

Helmer, IN, used to have an old wood up-and-over bridge for IN-327 over the Indiana Northeastern/Wabash RR. It looks like you can see a "land scar" of the old bridge in a contemporary satellite image. Note that this track did not go through a cut. The ramps had to go up the full height needed to clear a train. Since the ramps were short, they were steep.

Unlike the teenagers around Vermont, IL, you did not need this bridge to experience negative Gs. IN-327 itself was built with minimum grading so a segment over hilly land behaved like a roller coaster. At the old legal speed limit of 65mph you lost noticeable weight at the top of each hill.

In addition to weight limits, I'm surprised they don't specify a minimum distance between axles. It struck me that you could easily have the front axles going down while the rear axles are still going up and the body would end up stuck on the top of the bridge. The number of trains on these tracks is low enough that I'm sure the farmers would rather trade waiting for an occasional train to go through a grade crossing for being able to use modern grain trailer trucks in this area. As you can see in the photo below of the trucks lined up to unload at the South Milford grain elevator, grain trailers have two hoppers underneath so they have less road clearance than a normal semi-trailer. BTW (by the way), this grain elevator is why the former-Wabash tracks still exist in Helmer, IN.

20151030 5150, cropped
These wood bridges were not unique to CB&Q by any means. There used to be two of them in a row south of IN-130 over the CFE/CSX/Pennsy and NS/NKP. Unfortunately, by the time I got my new camera in 2014, they had been replaced. Satellite images show that they moved the CFE track closer to the NKP track so that one, shorter bridge can cross both railroads. I guess they never plan to double track either route again. According to Historic Aerials, the bridges were replaced between 1998 and 2003.

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