German Chancellor Angela Merkel, French President Francois Hollande and Italian Prime Minister Matteo Renzi will join Swiss authorities for a ceremonial first run through the tunnel on Wednesday. Full service will begin in December.
The tunnel runs between Erstfeld in central Switzerland's Uri canton and Bodio in the southern Ticino region. Railway trains traveling at speeds up to 200 kilometers per hour will cut the journey between Zurich and Milan by roughly an hour, to two hours and 40 minutes.
The tunnel was built in 17 years by 2,400 workers, at a cost of over $12 billion. The massive rig used to bore through the mountains, measured at 410 meters long, removed 28 million tons of rock.