Four trains 500 metres (a third of a mile) long, each carrying between 500 and 700 tonnes of rubbish, are to make the 44-hour journey every week to the northern German city, where it will be burned at a waste plant.
The city state has undertaken to dispose of 30,000 tonnes of rubbish over the next 10 weeks as part of a pledge by Germany to take in a total of 160,000 tonnes. Other German states will also contribute.
Tens of thousands of tonnes of waste have piled up in Naples and in the Campania region since late last year as a 14-year problem over a lack of incinerators reached a new peak.