The Berlin-Hamburg railway line reopened on Sunday after over 10 months of major renovation works, rail operator Deutsche Bahn said.
The first long-distance passenger train departed Hamburg central station at 5:36 am (0336 GMT), with two minutes' delay.
"The line has reopened, and the first trains are now running between Hamburg and Berlin," Deutsche Bahn said.
"Freight trains began running on the newly refurbished line as early as yesterday evening," the company added.
Berlin-Hamburg is considered the most important direct connection between two cities on the long-distance rail network in Germany.
Deutsche Bahn previously reopened a first section in mid-May, and trains have since been running continuously between Hamburg and Schwerin in northern Germany.
The major overhaul began in August 2025. Deutsche Bahn replaced tracks, switches and signals, and modernized 28 stations.
The completion of the works was delayed by around one and a half months, which Deutsche Bahn attributed to frost at the start of the year.
The overhaul was originally budgeted at €2.2 billion ($2.54 billion).
During the renovation, long-distance and freight trains had to take longer alternative routes. Regional trains ran on partial sections of the line and passengers had to use buses, with more than 200 buses deployed.
Deutsche Bahn urged passengers to check the exact departure time before travelling on Sunday.
"With a service launch on this scale, there may be some teething problems at first," the company said.
