Can you imagine a tram line that once was designed for something completely different? That’s the story of the Tramtunnel Milchbuck–Schwamendingen in Zurich. This isn’t just any tram tunnel. It’s a tunnel with a past.
Originally, this 2.5-kilometer stretch was intended for a U-Bahn, a full-fledged underground railway. Construction began in the 1970s. But in 1973, Zurich residents rejected the U-Bahn project. The tunnel sat unused for over a decade.
But Zurich is a city of innovation. Rather than let the concrete shell go to waste, the city decided to repurpose it for trams. On February 1, 1986, the Tramtunnel Milchbuck–Schwamendingen was opened for tram lines 7 and 9.
This tunnel has three underground stations: Tierspital, Waldgarten and Schörlistrasse. These stations were built to U-Bahn standards. That means they have island platforms that are 138 meters long and six meters wide.
Now here’s a quirky detail. Zurich’s trams are unidirectional. They only have doors on the right side. To use the U-Bahn platforms, trams had to run on the left side of the track inside the tunnel. This is the opposite of normal tram operation in Zurich.
To make this happen, engineers created two crossovers where the tunnel meets the rest of the tram network. At Schwamendingerplatz, there’s a conventional diamond crossing. But at the Milchbuck portal, things get interesting. There is an underground flying junction. This leads to two single-track ramps. These ramps merge into a web of surface tracks. It is located beside a reversing loop. It is an unusual configuration that allows the trams to switch sides safely.
The Tramtunnel Milchbuck–Schwamendingen has seen several upgrades. From May 2011 to October 2012, the stations and entrances were renovated. New escalators were installed. These escalators were the first in Switzerland to operate in both directions. The tunnel also received a new train protection system in 2016. This system uses signals to prevent trams from getting too close to each other.
The Tramtunnel Milchbuck–Schwamendingen is more than just a way to get from Milchbuck to Schwamendingen. It is a symbol of Zurich’s resourcefulness. It represents how a city can adapt and reuse infrastructure. What was once meant for a failed U-Bahn project now efficiently serves Zurich’s tram network. As you travel through this tunnel, remember its unique history. Remember how Zurich turned a dream into reality.