Looks like the strike might have hit right on the transom through the decking and knocked the columns down (wow). Both sets of lanes went down—not only the outer set. The train above might have caught the splatter/ricochet from the hit on the lower lanes.
Kerch Bridge On Fire After an Explosion (Video of Strike Included)
https://en.defence-ua.com/news/kerch_bridge_on_fire_after_explosion_videos-4466.html
More video, live?
https://www.youtube.com/watch?v=5mLOO-krTcI