@Eric_ours_polaire Seems to be CAF: https://nl.wikipedia.org/wiki/Dubbeldekker_Nieuwe_Generatie

And yep, they're intended for intercity services (as is true for all blue/yellow NS trains; stop trains have white added to the livery).

I expect that the mix of single/double-deck is mainly for accessibility reasons (step-free access), while still maintaining high capacity.