How about we wait to hear the actual cause of the derailment instead of guessing?
If we wait to hear, we might wait forever. Or the publicly-released information might be very vague (e.g., "a track defect"). PAR generally releases as little info as possible, as we all know.
From a forum moderation standpoint, I'm fine with members having general discussions of possible causes, as long as they're not declaring any of those possibilities to be facts in this particular incident. Likewise, if a member has information that they've received from a reliable source and they want to share it, that's fine too... but only if they've received it directly from the source. "I heard it from a fellow railfan who heard it from another railfan who heard it from the deputy fire chief who heard it from a MoW worker" is not reliable.