I wasn't specific about how quickly a railway bridge could be replaced during wartime when I wrote about pontoon bridges or about the Baltic Invasion scenario. The reason was that researching this topic wasn't very fruitful.
Now I learned why; apparently,
"H-17. The MAN SE railway bridge is a panel bridge that is similar to the Bailey bridge but is much stronger. It has two configurations: upper deck and lower deck. With the upper deck configuration, it can span gaps up to 40.95 meters; with the lower deck up to 50.4 meters. It is designed to withstand the crossing of locomotives with 30 tons per axle and wagons with 20 tons per axle. Installation time is 20 to 30 hours with a 50-man crew and two cranes. This bridge requires a prepared abutment (existing railway abutments or concrete abutment). Spain and Italy are the only NATO countries with existing military railway bridges in their inventory."
source: FM 3-90.12/MCWP 3-17.1 (FM 90-13), page H-17, (July 2008)
Well, it's difficult to find info if there's hardly anything in existence. Thus this is not a blog article about military engineers' railway bridges as much as about them not having the same.
There is an important Oder bridge at the border between Germany and Poland. I suppose the central span over the water (104 m long) could be taken down by two well-aimed cruise missile hits. The MAN SE railway bridge would be less than half as long as needed.
Maybe there's a way to realise a railway pontoon bridge, but you'd need to lay the rail lines to and from it as well, and would still suffer from the vulnerability of the mostly unguarded rail lines and their signal systems.
This marginal capability to reconnect railway lines of communication reflects the reduced reliance of armed forces on railway transportation; we can make do with roads nowadays, though particularly tank transporter semi-trailers are in rather short supply for this.