Rather than champagne, it was a bottle of Berliner Weisse – the sour-tasting traditional beer of the capital that drinkers sweeten with fruit syrup – that Müller smashed on the metal skin of the new train, which will henceforth be called "Icke" (or "me" in Berlin dialect), Tagesspiegel reported.
Icke's first trip saw it make a non-stop run from Warschauer Straße to Zoologischer Garten and back along the U12 line through the Kreuzberg district south of the city centre.
Passengers who won places aboard the special trip were impressed by the low level of noise inside the train.
"You can actually have a very nice conversation inside here," Martina Langschwager told Tagesspiegel.
Like other more recent U-Bahn trains, Icke boasts carriages that are completely linked together in the interests of convenience and security.
The interior of Berlin BVG's new "Icke" U-Bahn trains. Photo: DPA
And thanks to a redesign of the train's skin, designers have squeezed ten centimetres of extra width into the cabin.
The BVG (Berlin public transport company) has ordered 37 of the new trains for lines 1 through 4.
Most existing rolling stock on the U-Bahn network is more than 26 years old, BVG board chairwoman Sigrid Evelyn Nikutta said at the christening event, meaning that the company must spend €2 billion on new trains by 2020.
The new Icke trains are expected to be in service for at least 40 years.