Rail fans and record junkies rejoiced Wednesday when Switzerland unveiled the world’s longest and deepest railroad tunnel.  The new bore, called the Gotthard Base Tunnel, runs between the towns of Erstfeld in the north and Bodio in the south and goes straight through Gotthard Mountain, a 7,000-foot peak in the Swiss Alps. It is 35.5 miles long, two miles longer than the previous record-holder, Japan’s Seikan Tunnel. What’s more, some sections of the new Swiss tunnel lie a record 1.4 miles beneath the mountain’s peak.

Once it’s fully operational (probably in December), the tunnel will carry 260 freight trains and 65 passenger trains a day, with each trip taking about 20 minutes at speeds up to 150 mph. All of this traffic is part a plan to cut down on pollution by taking traffic off of one of the busiest roads in the region and getting more people and goods on trains.

The tunnel also will have a significant impact on regional tourism by eventually creating a high-speed rail line that will run all the way from Rotterdam, in The Netherlands, to Genoa, Italy. Even before that happens, the journey between Zurich, Switzerland and Milan, Italy on existing rails will be reduced to two hours and 40 minutes.

The Gotthard project has been a long time coming. Voters originally approved the tunnel construction in 1992 (though work didn’t begin until in 1996). Excavation was completed in 2010 after crews removed more than 28 million tons of rock—most of which was pulverized and incorporated into concrete to put back into the tunnel. 

According to a report from the BBC, construction of the tunnel was not without its challenges. First, engineers had to blast through more than 70 different kinds of rock, “some as hard as granite, others as soft as sugar.” Next, because some of the sections of the tunnel pass through rock that geologists consider “hazardous,” engineers had to using steel arches to support the excavation, a technology borrowed from mining. Finally, engineering crews had to deal with dangerous temperatures; because temps at the deepest spots exceeded 100 degrees, the team had to cool the air to protect the 2,600 workers excavating the rock.

All told, the project cost the Swiss government $10 billion, making it one of the most expensive public works projects in the country’s history. The tunnel is being financed by taxes, tolls (on heavy vehicles only), and loans that are due to be repaid within a decade.

Matt Villano is a freelance writer and editor based in Healdsburg, California. In more than 18 years as a full-time freelancer, he has covered travel for publications including TIME, the Wall Street Journal, the New York Times, Sunset, Backpacker, Alaska Airlinesand more. He is a senior editor for the Expedia Viewfinder blog and writes a monthly food column for Islands magazine. Villano also serves on the board of the Family Travel Association and blogs about family travel at Wandering Pod. Learn more about him at Whalehead.com.