But why a bridge? If they have a plane, particularly a DC-10 as pictured, why waste it on just a bridge? Minimal body count.
The Hell Gate Bridge, today has the 17th longest main steel arch span in the world, and continues to play a central role in rail transportation in the Northeast. Only three of the four tracks are used on the bridge. The two south tracks carry Amtrak Northeast Corridor trains, while the north inner track carries CSX and Norfolk Southern (the owners of the former Conrail routes) freight trains. The north outer track is no longer in operation.
I batted this around some with 'Zilla some time ago. I'm of the opinion that if they have a limited access to their method of destruction, be it aircraft, explosive or even nuke or combo thereof, then a high body count is the ticket. But say the attacks are far wider ranging encompassing multiple levels.
Level one is the primary set of teams: The nuke/WMD stuff or multiple aircraft strikes, say ten. The next level is the infiltrated suicide/truck bombers. These would have specific missions and contingencies. Level three is the random shooter who take targets of opportunity at random, surely the most difficult to interdict. Level three has no "handler" and perhaps has a universal "GO" code. Remember 911 was the "tip of the finger" while the next attack would be the rest of that finger.
IF it's big enough, then taking down a span across the Mississippi or Ohio rivers makes perfect sense. It would be a major blow to the American economy and literally divide the country into geographical sections. They want to "tear us apart." of course the barriers could be easily overcome, via air, etc but the symbolic damage would be worse than 911. And take longer to clear.
Well, my thinking is a bridge is not just a bridge.
Taking out such a structure would cause maximum damage to the economy, to life in general. Depending on the bridge of course. It wouldn't be a body count issue, but disruption of the economy, life, etc.
There are bridges all around NYC that would fit that bill, as well as any number of other sites.