Nothing to suggest so far 1K50 was involved in any other way apart from making the emergency call to report 2K71 has derailed.

Pretty sure 1K50 isn't involved as I've been sent an image of the view of the derailment from 1K50 and it doesn't look like a collision has taken place as 1K50 is quite a distance from the derailment.
(Photo attached showing a view of the derailment from 1K50)
