Teething issues as Melbourne Metro Tunnel finally opens after years of delays

Melbourne's Metro Tunnel has opened to passengers this morning, albeit with some minor hiccups.

The project, which cost $15 billion and has been hampered by delays and setbacks, added five new stations, with the first trains hitting the rails just after 9am.

Melburnians have flocked to try out the extension with massive crowds at all stations, though some delays and minor issues have been experienced.

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There were delays of up to 15 minutes after a fire alarm went off near Anzac Station, forcing trains to remain idle, though those delays are clearing according to Metro Trains' official website.

There has also been escalator outages at Parkville Station and State Library Station, according to The Age.

The other new stations opening today are Town Hall and Arden, with the new line running for almost 100 kilometres.

It represents the biggest upgrade to Melbourne's rail in 40 years, doubling the size of the city's underground rail network and will ease congestion on the city loop.

It is a project that has been years in the making, with tunnelling beginning in 2019.

Boring machines were digging as deep as 40 metres underneath Melbourne to create the tunnels, the most striking of which are two twin tunnels that run for nine kilometres.

The opening is not without controversy, with the firefighters union wanting to delay it due to claims about dangerous radio faults within the new network.

Victorian Premier Jacinta Allan claimed it was a scare tactic to try and secure better pay, rather than publicising any actual safety concerns.

"The claims that have been made by the union today are wrong and they've also been clearly rejected by the rail safety regulator, who is the expert on this matter," Allan said.

"These claims are being made perhaps more for industrial purposes than anything else."

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