Thank you for your feedback! One of our travelers has written to us to comment on the transportation system in Germany, with the following helpful information:
In Germany, locals buy weekly, monthly, or even annual riding passes. While there are no ticket gates like in London, plain clothes police make their rounds on all public transport. Being caught without a ticket is an automatic 40 Euro fine payable to the officer.
We hope this information helps you, and future travelers during your stay in Hamburg!