High up in the Sierra Nevada mountains in California, half hidden by a snow drift, a disused railway tunnel is a monument to the Chinese labourers who helped build modern America in the 1860s. Now, 150 years later, the Chinese could be returning to build the next generation of US railways, but in a very different role.

Between 10,000 and 20,000 Chinese workers took a year to cut the Summit Tunnel, a key section of the first trans-continental railroad, through solid rock near the town of Truckee.

The American railroad opened up the West, spawning towns and cities all along its route.

But while freight still helps drive the world’s biggest economy, passenger trains are often slow and unreliable.

In a country where an American’s car is his or her castle, trains have fallen behind