TFA indicates a 40cm gap — huge!
No, that gap was created after the rail broke and the train derailed as a result.
The crack was in the weld, causing one side to sink and the wheel to hit the start of the next section of rail which was no longer welded to it, causing stress fractures to form in the rail which later caused that 40cm piece to break off.
I suppose that counts/was caused by a fracture but almost a half meter of gap in the track is nuts. Like describing a limb that’s totally removed as a bone fracture.
Though conceivably the break was very small and a train impacting the slightly lifted rail just caused a good chunk of it to explode.