Only looking at width of bridges and tunnels cannot be conclusive, as sometimes they provide sidewalks, escape routes, or even parallel approach roads alongwith the tracks - but not enough space for the 2nd track. For example, look at Pir Panjal Railway tunnel, which is very much a part of USBRL project. click here
Look at the photo on this wikipedia page. The tunnel cannot house a second track in any case, though it is wider than say a Konkan Railway or CR ghat section tunnel.
Going by this example, I doubt they've...
more... planned 2nd line anywhere on the section. Though I would love to be proved wrong in this respect.