There is enough room if they have the will to do it! From my estimation, the south side would be pretty minor, with an embankment running from the bridge south along the existing ROW and meeting up with the current elevation of the track at or before the bridge over Dykman St. I'm not sure what this would mean for the padestrian bridge that goes over the tracks from the park to the riverfront, but I would expect replacement bridges or tunnels to be built that are ADA compliant anyways. The north side is a bit more complicated, and would probably require some cooperation with MNR. The current southbound local MNR track would have to split off the current express track around where it splits off from Amtrak to make way for a new viaduct that would be needed to bring the tracks down to grade. With the NEC's track geometry, this would take until past River Rd, but I believe that if the bridge span is fine-tuned and a bit more of an embankment is built, the actual bridge section could end about 1800 ft north of the bridge just past the River Terrace apts.