Looking over the news footage, I have noticed several things:

1) All of the bridge beams look great, no signs of rust, evenly applied protective coatings.

2) This Collapse (domino) Pattern reminds me of either an Earthquake Effect (per the USGS website, no current activity) or a militarily applied solution to a crucial bridge target.

a) Notice that the ramp on one side of the river is still standing while the river span and the entire ramp on the opposite river bank has all collapsed.

b) This collapse has negated the use of a railroad track, the Upper Mississippi River above (6 miles of navigable waterway???)the collapse. It has restricted the use of (created a chokepoint) of an Interstate Highway (I-35). It has negated the use of a USA COE Lock, as well.

c) Could this have been a better soft target for domestic or imported terrorist???? It would provide a lot of bang for the buck!!!!

3) I find it interesting that a train was passing underneath the bridge at, what appears to me, to be the point of initial piling failure/collapse.

a) Most of that long train had already passed under the bridge and there were 6-7 cars left to pass when the bridge collapsed on top of it.

b) I am wondering about the associated vibrations of a long train moving at slow speeds.

4) My initial conclusion is that the train passing underneath what appears, to me, the collapse point, has to have a connection to the collapse of the bridge, based on what I observed via CNN's coverage.

5) No, I am NOT an ENGINEER!!!!

6) What do the Engineers on ETS think???