The decision was made to construct the bridge off to the side of the road on a separate spot, then to create a special purpose roadway across the road to the location where the bridge would be placed. And finally, to move the bridge from the construction site to the final destination in one piece.
The whole thing was conceived and executed according to plan, including a < 24 hour closure of the road and one week of interruption on the rail line (it was not possible for many reasons to have the track installed prior to moving the bridge).
That is engineering. In the 'move fast and break stuff' world that would be 'move fast and kill people'.
If this were software we'd be looking at a multi-year software project with a few hundred programmers delivered on-time, within the budget and working flawlessly on the day of delivery.
I have yet to see such a project. But as you say, 'Amazing!', the fact that you make it seem like this is 'no big deal' is exactly what is so good about it, you fully expected it to work didn't you?
The trick apparently is to make the complex and impressive stuff look so boring, I really wished that we could make software look that boring.