Doesn't surprise me too much. The excavator arm was pointed forward,
caught the bridge beam, and then tilted up and back. The main forces on
the excavator put the first arm into straight compression with all the
resulting force into the base casting of the frame and then out to the
tracks. No bending moments involved. The main cylinders would have been
in tension, that will blow the seals and end caps out, again, no big
damage. In one of the pictures in the middle of the sequence, you can
see the right side main cylinder sticking straight up, no shaft sticking
out. The left side cylinder is intact, must mean that the lower mount or
eye is broken.

Ignoramus21938 wrote:
On 2008-03-22, RoyJ wrote:
From the looks of things, the cleanup cost $134,000, the offending span
was completely replaced at a cost of about half million.

http://c141heaven.us/jokes/truck_bridge.html
Scroll down to the bottom for a June news article.

It is amazing how little visible damage was sustained by the Huindai
excavator.