[freerover]

I think the trail on both sides is easy. You just need an arch gap in the bridge supports for people to pass under. It doesn't need to have 20' clearance. I feel like blue line goes underground at the MACC parking lot, goes down red river, uses the corner of the convention center to round that corner to 4th with an underground station at the fire station parking lot. The future gold line would keep going north on Red River instead of Trinity. I assume you would need each tunnel at different elevations for turning clearance and so you can have the future gold line split without crossing into opposing train tracks.