rail reservations Berlin-Hamburg-Cologne?

I always reserved seats when I lived in Germany (when available). Not to guarantee a seat. There's always seats unoccupied. The reason is because with a reservation, I know exactly which carriage to board and I can procede directly to my empty waiting seat. Without a reservation, particularly on a crowded train, I might have to fumble around with my luggage until I find a vacancy, sometimes moving through more than one carriage. So, it's more for the convenience than anything else.

I would expect that Hamburg to Köln on a Tuesday morning would likely be more filled than Berlin to Hamburg on a Saturday morning.

If you want those optional seat assignments for trains within Germany, you can get them either in train stations or on the DB web site for about €4.50 per person. Double check that your friend didn't get a seat assignment (car number and seat number) during her purchase, since it's usually offered.

Hi,

The trip on Sat. morning Berlin Hbf to Hamburg Hbf certainly needs no reservation on the ICE. That's a bit more than one and three quarter hours. For Hamburg Hbf to Köln Hbf during rush hour on Tues. morning, if you want to sit together, better to reserve.

Thanks to all of you for the advice...just what I wanted to know.