Geneva ? A massive drilling machine called Sissi is about to chew through the last few inches of rock standing in the way of the creation of the world’s longest tunnel.

The expected completion today of the 35.4-mile Gotthard Base rail tunnel is being hailed as an environmental triumph as much as an unprecedented engineering feat.

The $10 billion tube bores through the Gotthard massif, including the 8200-foot Piz Vatgira, along the route to Italy. It’s part of a larger project to shift the haulage of goods from roads to rails, spurred mainly by a concern that heavy trucks were destroying Switzerland’s pristine Alpine landscape.

Swiss voters, who are paying more than $1,300 each to fund the project, approved its construction in a series of referendums almost 20 years ago.