Full-speed testing has begun through the world’s longest rail tunnel.

AlpTransit Gotthard AG completed its first test run at 275 km/h on November 8 using its hired ICE-S train from Deutsche Bahn (DB).

More than 500 test runs have been completed in the first 50 days of testing through the tunnel. In February, testing of freight trains will also begin.

A crew of 160 drivers and engineers make up the testing team.

The Gotthard Base Tunnel is due to open in June 1, 2016, but it won’t see a commercial service running through it until December.