This question already has an answer here:
I had a train ticket from Antwerp Central to Schipol Airport on Thalys in the evening, connecting to a KLM flight from Amsterdam to Mumbai, operated by Jet Airways the next day.
I collected the ticket in the morning but have missed the Thalys. As my flight is the next day I'm thinking of catching a train tomorrow and going to Schipol.
Will they let me check in?