The 20.45 from Leeds is currently sat in Retford. Personally, if it was a long delay I'd much rather be on a platform than in the middle of nowhere. Happened to me once, 3-odd hours on p11 at Edinburgh!
As Yorkie said, it could (unfortunately) be a while, as far as infrastructure damage is concerned let alone persons hit by trains it's anyone's guess. Would depend a lot on the scale of the damage. Job stopped Peterborough - Hitchin and the problems appear to be in the Huntington/St. Neots area. There does appear to be a rescue train in the area but other than that nothing concrete to report unfortunately.