Awesome work Nick

It is indeed possible to make your Bridge functional with the DBE. I will describe the steps below...

Never mind the reskin in on this demonstration! I will show why later in this post.
So basically to get an orthogonal segment of the rail network you can do the following...
1) Draw over the road with the Rail network.
2) The network will be DTR as a default so you will have to override it to STR.
3) Once the water is put back in place you will have something like in the picture below...

Now here is why I was using the reskin...
I have made some RRW default to Reskin that can be overridden to STR as well as the default DTR as shown below...

For the bridge I recommend making it into pieces such as an end piece and a middle piece.
Thanks for all your great creations

I hope the method I described was constructive for you?
-eggman121 (Stephen)