Frau A and I spent a weekend in Cologne recently.
On Sunday morning, our plan was this: after checking out of the hotel, we'd place our suitcases in a locker at the train station, spend the day sightseeing in town, then retrieve the luggage before boarding the train to the airport.
We expected to find the typical long rows of metal lockers, where you insert some euros, get a key, etc..
Instead, we found this newer system that automatically conveys, stores, and retrieves the bags.
That morning we found the machine, put in our suitcases, and received a card identifying our luggage.
The video below was shot late that afternoon, as Frau A paid for and retrieved one of the suitcases.
The animation of the bag being run along the conveyor is pretty funny. But it works quite quickly, no?
There's even a phone number on the machine to call if you happen to lose the card that the system gives you.
Although it's more expensive than a DIY locker, it seems to be a much better use of floor space in the Hauptbahnhof.