I've been working on an N scale around-the-room layout. I left a section open to avoid a duckunder, but I still need to get trains across. I want to build a removable bridge. I've got 4 tracks to get from one side to the other, 2 on the main level, and 2 about 6" higher. Has anyone tried building a double decked bridge? Does any one have suggestions on how to keep it steady and have the tracks line up exactly but still easy to get out of the way? I also haven't figured out how to wire it so I don't have to unplug it when I need move it.