This bridge design was originally downloaded by me (I don't remember the name of the original designer who created the bridge) from the LEGO Factory / Design By ME page in 2010-ish and was never built in real life due to questions about it's strength. I came across it again while looking at my MOCpage account's older files and made it into the version seen above using newer parts and a longer frame.
The bridge fits any of my trains, and should fit all official LEGO trains except for double stack containers such as sets 10219 (Maersk Train) and 10170 (TTX Intermodal Double-Stack Car).
Side view of the bridge.
The old design is on the left, new is on the right. (NOTE: The new bridge is in the LDD file, but the old one is NOT!)
EDIT 12/7/17: Revised the diagonal bridge supports to fit into place, thanks to Wes Turngate over on Flickr. The LDD file has been updated as of now.