Costing nearly $10 million, it will be one of Europe's most expensive train lines once finished and Brussels considers the transport corridor between Lyon in France and Turin in Italy important for Europe.
But leaders in Italy's Five Star Movement, evoking the "yellow vest" protesters besieging French President Emmanuel Macron, have called it a waste of money and have said it is not what ordinary citizens need.
Macron, for his part, called new populist parties, of which the Five Star Movement is one, a form of political leprosy.
Thousands of locals in Italy are determined to see the project abandoned and diplomatic relations between the two countries have continued to unravel; although machines continue to work on the trans-Alpine railway, they may be digging a tunnel to nowhere.
Al Jazeera's David Chater reports.
