In that sentence, "down" doesn't give any real extra information. We would know just as much from "I see there's been trouble at the factory". The use of "down", however, indicates that the speaker and listener are probably locals, they both know which factory is being talked about and possibly that the speaker lives either north or uphill of the factory.
You'll hear BrE speakers use these kind of directional words quite frequently, with no useful meaning.
I'm going down the shops. Do you want anything?
She's gone down the pub.
He's heading up to town.
They're going up to Mark's parents this weekend.
I'm going round [to] Sarah's later.