An "Upside-Down" Bridge?

Or Just A Way to Save Money?

The story of The Erie Canal becomes more interesting the more it's told.  Enjoy each of our Classroom Collection video clips, and don't forget to scroll down this page for more images and information!

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The railroad bridge in the distance looks upside down
The picture above is a view overlooking Lockport's famous "Flight of Five" looking east. The railroad bridge you see crossing the canal in the distance doesn't look like most other bridges. Trains cross this bridge on the very top, and the trusswork that gives the bridge strength between supports is beneath the tracks, rather than above. This makes the bridge appear to have been built upside-down.
This bridge looks like it was built upside-down
Tour guides at the site like to explain the unusual bridge by saying that because railroads were in competition with the canal for freight cargo business, they used the hanging bridge trusswork as a way to limit the size of ships that could navigate on the canal. If you visit Lockport and hear this on one of the tours, don't believe it. The real reason is far less interesting, but much more sensible. Bridge truss-work is built above the traffic - in this case the railroad - only when there's not enough room underneath the bridge to do it this way. Building it above means that the bridge has to be wider to accomodate both the traffic AND the truss-work. That means more material and higher building costs. Here the clearance from the water to the railroad bed was far enough to allow the railroad to save some money by building a narrower bridge with the truss-work beneath, with plenty of room to spare for canal traffic.
A bowstring truss bridge over the Erie Canal at Lockport
In case you're still not convinced, consider the highway bridges you see in the distance in this shot taken from the top of the "upside down" bridge. The railroad engineers weren't concerned about tall ships getting under their bridge. They knew that the waterway was already crossed by hundreds of bridges like these that were a lot lower than the one they were building here for the railroad.
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