Sydney commuters will be able to use their phones and access the internet inside train tunnels on the City Circle line for the first time, after a network infrastructure upgrade.
The NSW government has been working with Optus, Telstra and Vodafone, to install more than 10 kilometres of cabling to provide reception for mobile phones, tablets and laptops.
The service is undergoing live testing and will be switched on as early as Monday, Transport Minister Gladys Berejiklian said.
"The lack of coverage in our CBD tunnels has been an ongoing concern for customers over many years and quite frankly an embarrassment for our city," she said.
More than 400,000 commuters will benefit from the new infrastructure upgrade, Ms Berejiklian said.
The rollout will continue on the Eastern Suburbs Line, with work underway to install 18 kilometres of cable between Erskineville and Bondi Junction.
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