First a little background as to why the news is a big deal.
The Kerch strait bridge connects the eastern end of Crimea to Russia. It has two rail lines and two two-lane roadways. It WAS the only safe road/rail line supporting Russian forces on the Kherson/trans-Dnieper front. Supplies/ troops transiting north of Crimea are within range of Ukrainian artillery. The high quality roads in this part of the world are what we would call good country roads. Their country roads we would call unimproved dirt roads.
The bomb that dropped two sections of one side of the road bridge also set the fuel tank cars of a passing train on fire. The actual strait is to the left of the photo. The bulk of Russian wheat exports pass through the Kerch strait. The picture looks north. 
The Russians just got the rail line cleared and inspected today. Rails of both sets of tracks were deformed and must be replaced. This will not be convenient. It will take several weeks to be repaired at best. What is not known, at least to me, is whether or not the rebar and/or concrete of the supporting track bed was damaged enough to make it unusable. If it is, one or both sides of the rail line can be out for several months.
So, what does this all mean?
It means that for at least another 2-3 weeks the Russian forces in the Kherson region will be critically short of fuel. I counted 20 tank cars on that particular train. The Russians probably run at least that many a day. It would take two large military fuel-bowser trucks to replace each tank car. Unfortunately for the Russians, most of their military trucks have been destroyed. It would take roughly six civilian trucks to replace each tank car.
Now consider the distance those trucks would have to drive over bad roads through a war zone. They are looking at needing 700-1000 fuel trucks just to keep the Kherson front supplied.
I'm not sure the Russians can come up with 120 civilian tanker trucks, much less 700-1000 they really need. And if they are transporting military fuel they aren't taking care of their civilian customers further damaging the Russian economy and driving up discontent at home.
I'm going to end this here. It is already much longer than I had intended to make this.
WWG1WGA
Garde la Foi, mes amis! Nous nous sommes les sauveurs de la République! Maintenant et Toujours!
(Keep the Faith, my friends! We are the saviors of the Republic! Now and Forever!)
LonePalm, le Républicain du verre cassé (The Broken Glass Republican)