These ICE are normal daytime trains-the long white sleek trains and yes, jawel dame, these indeed have only seats-and as all such trains in DE by DB have only optional REServ it is indeed the case-I´ve used this quite a few times. It was not even overly busy last week (midweek day)-but can be different on weekends and when holidays really start. They are in fact mostly aimed at bringing people to very early flites from FRA airprot-where they stand for quite some time. You arr M HBF just after 6.00-see loads of food places in the tunnel to left hand side above the S-bahn tracks. Starts with a green REWE-lokal, but the above Yorma is my favorite.

DO note that you need to use 2nd travelday next morning from M onward-and times >12.00 are always PM-even without saying (USAers cannot count >12 and thus for them 13.33= 1.33 PM).

ICE trains generally do not require a reservation. If a journey is marked with orange text stating “Seat reservations required” then you'll need to book seats for a particular train. If there is no additional text, then you can safely assume that no reservation is required.