I know Bendorsey has done a ton of them. Search his name on the DLS (check 04 box too). Though it may take you a while to find what you need as he has done a lot.
You could also do a title search for FMA on the DLS (04 box). Their arch bridges are curveable, maybe a few others too.
I've tried downloading Bendoreys Curved Trestles but they all go red in the Download Helper bit of the DLS and won't download, is this because they are not TS12 compliant???
The were made for TRS2004. Try running them thru CCP. They don't have any fancy stuff in them (just lots and lots of track attchment points).
Oops - just realized you can't as they never make it into TS2012 (sorry - my booboo).
I see you have TS2010 - try downloading them to that and if successful run them thru its CCP. Then transfer them from 2010 to 2012 (however you do that, lol).