The train in question has been running for many years (formerly as the Ost-West Express), with a variety of western termini (it's a pity it doesn't go to Brussels any more). I think it's been running from/to Amsterdam for a few years (since sometime between 2006 and 2009, according to the copies of the Thomas Cook timetable I have to hand). It was nearly withdrawn earlier this year but had a last-minute reprieve.
If you go back far enough (early 1990s) there was a through train from Warsaw (and other places) to the Hook of Holland, but I don't know if it ever had an Amsterdam portion, or ran via Amsterdam.
(Apologies if the OP knows this already or if it's beyond the scope of their question, but someone might be interested!)