Originally Posted by Another user name to remember

Be careful: KLM does actually fly to Brussels too. If your inbound is delayed, missing your train, you might end up being re-booked on a real flight to Brussels. You do not take that flight, the rest of your ticket is cancelled. Happened to me once at the end of trip and instead of disembarking a train in Rotterdam, I needed half a day extra to get home. Checked luggage, so nothing I could do about it.