Sadly, not an answer.
I've had mixed results with re-rail portal. I had given up on it working and added the delete derailed trains rule and was testing that when the rerial portal put up a message that it was handling the derailment. (which it did, a little more than the minute later that it was set for). when it wasn't working it seemed that the derailment was blocking its access to the track (of course it was going to delete that train before replacing it, but...).
All I know is if it's going to work you will see a message immediately following the "Consist xx has derailed" telling you the rerail portal is handling it.
Wish I knew why this works sometimes and not others. (come to think about it there's very little about trainz where that's not true)
Any insight would be greatly appreciated.
chris