This is from a few years ago, but still interesting for those who care about infrastructure:

https://youtu.be/8IRO3BygLOI

Captions are in German, but most of the action is self-evident. Basically covers three days.

They lifted out an old multi-segment bridge that had been the cause of a speed restriction and replaced it with a single new bridge that had been pre-built and which was hydraulically pushed into place once the old segments were gone.

Notice that they didn't even have to tear out the catenary to do this work. (I presume they may have had to make some minor adjustments before traffic resumed.) The new bridge also had an initial layer of ballast before it was even moved into place.