Elon Musk tweets photo of his giant tunnel boring machine

The entire Los Angeles County Light Rail system was built above ground because going underground was cost prohibitive. Who is going to pay for this charade?

Is Elon Musk taking his Hyperloop concept underground? After being stuck in heavy traffic in December, the billionaire came up with a plan to create a giant tunnel under Los Angeles to ease congestion.

'Traffic is driving me nuts. Am going to build a tunnel boring machine and just start digging…', he tweeted.

And he wasn't joking.

Musk has now tweeted an image of what appears to be a tunnel boring machine (TBM) that many believe will do just that – and his SpaceX firm has started digging a large trench near its Hawthorne HQ to test the machine.

Elon Musk may have dreamt up his latest world-changing technology while stuck in heavy traffic.

In December he tweeted: 'Traffic is driving me nuts. Am going to build a tunnel boring machine and just start digging…'.

'It shall be called ''The Boring Company',' he added.

Musk even proposed a suggested slogan for the company: 'Boring, it's what we do.'

The idea might seem like a joke, but Musk ended his series of tweets with 'I am actually going to do this'.

He posted the photo with the caption 'Minecraft' – a reference to the popular video game in which players dig large tunnel networks for resources.

When Musk first announced his plans to bore a tunnel to his SpaceX offices in Los Angeles, it was hard to know if he was simply venting his frustrations about being stuck in traffic.

But he ended his rant on Twitter with: 'I am actually going to do this'.

Musk has yet to confirm, however, whether the image of the tunnel boring machine he tweeted is his own, or its exact purpose.

The entrepreneur has a strong track record of getting ideas off the ground.

Musk has started two transportation related companies – Tesla for electric cars and SpaceX for launching into space.

He has also initiated the development of Hyperloop, a proposed method of travel that would transport people at 745mph (1,200km/h) between distant locations.

And it seems that Musk's tunneling work has already begun.