It's a semi-famous trestle from a railroad that has long since been abandoned. Its fame comes from the fact that it appeared on the back cover of R.E.M.'s album Murmur.
Image courtesy of Sleevage.com
There has been much discussion in the newspaper and online about whether or not to attempt to salvage the trestle. There doesn't appear to be a very good reason to save it, other than the fact that it was made famous by one of the local bands that happened to become very popular.
I'm guessing it will eventually be taken down out of concern for public safety. Either that or it will fall of its own accord.