Hack Brueken (Brueken - or Brücken - means 'bridges' in German...Thank you Google Translate!) creates pre-assembled metal bridges in an interesting array of styles and lengths (and in multiple scales). I came across these bridges on eBay and from the description seemed like a something worth checking out for my overpass on the 'red line'. I have to say, I am very pleased!
Despite being made of metal, they are very lightweight, and definitely feel more solid than any plastic kit you would purchase and assemble (well, maybe not you, but for me..... yeah, some of these plastic kits require far more dexterity and patience and skill with tweezers than I have, but that's another story....). While very close inspection does not show a lot of detail (e.g. no rivets), I find the general scale of the girders and beams to look a bit more 'realistic' than the usually much thicker 'plastic varieties'. I think each has its place, and the idea for me is to have a little bit of diversity on the layout for different lines, so it works for me to have both. Below is the Kato double-track bridge compared to a Hack single track bridge I'm using on my 'expansion':
So if you're looking for a bridge that is a bit different than the normally available ones, I'd recommend checking out "Hack"...either on eBay or on their website (I shouldn't have to say this, but I have no relationship with this company, just passing on some neat stuff I found).