Elon Musk unveils the first high-speed Boring hyperloop tunnel in California

Entrepreneur and Tesla chief Elon Musk has lifted the curtain on the first tunnel completed by his underground high-speed rail venture the Boring Company.

In a 30-minute presentation, Musk described the 1.14 mile tunnel as a breakthrough in counteracting the "soul-destroying" traffic of Los Angeles, California.

Despite previously suggesting the public would be offered free rides on the day, no such offer materialised at the grand opening. The Boring Company said tunnel tours became invitation-only after "unbelievably high demand".

Musk said the finished segment of the tunnel displayed late last night cost him around $10m (£7.9m), which included the costs of excavation, internal infrastructure, lighting, ventilation, safety systems, communications and a track. By comparison, he stipulated digging a mile of tunnel by more "traditional" methods would cost up to $1bn and take longer to complete.

A demonstration video showed a modified Tesla X car on the tracks, which was used to ferry passengers as a mini-train by retracting its wheels. 

Tesla in @boringcompany tunnel with retractable wheel gear that turns a car into a rail-guided train & back again pic.twitter.com/3a6i0NoSmi

— Elon Musk (@elonmusk) December 19, 2018

When fully operational, the hyperloop system will consist of "skate" platforms that can carry passengers and vehicles and zip through the tunnels by way of electric power. 

Musk abandoned attempts to build a second LA hyperloop tunnel last month, after litigation forced his firm to back down from the project.

The Tesla chief, who also runs rocket firm Space X, had plans to build the 2.7 mile-long Sepulveda tunnel on the western side of LA. Instead, the Boring Company will seek to build out its metropolitan network with a separate tunnel at Dodger Stadium, designed to channel baseball fans between games and one of three existing subway stations in LA.