We are ending an 11 day Frankfurt to Frankfurt tour of Germany the morning of 7/19/14. Then we are taking a "2 day"/1 night(7/19) excursion to Osnabrück via rail. We'll return to Frankfurt, spend our last night there(7/20) and fly back to Ohio on 7/21. I understand that one needs to minimize luggage on the trains, but I don't know what we can do with our larger suitcases for that 1 night while we go to Osnabrück. The hotel we're staying at with the tour company does NOT have a 3 person room available for that 1 night (or I'd see if we could keep it there til return, which I can't). Any thoughts, advice??
Just take your suitcase with you. There is plenty of space on the trains. Rather than stress about dropping it off, picking it up somewhere and the charges that might be involved, it is much easier to bring it along.
Any hotel that you have stayed at will hold the luggage for you, whether you book the last night there or not. How big is the larger suitcase you're bringing? Please give some consideration to packing light using the tips at http://www.ricksteves.com/travel-tips/packing-light, so that you can handle your bag yourself. Any airline carry-on sized bag will fit easily on the train, and larger suitcases are not unusual, either.