The first tunnelled section of the Elizabeth line in London now has high speed mobile coverage, Transport for London (TfL) has announced.
Passengers travelling between Liverpool Street and Paddington are now able to access 4G and 5G mobile coverage in the tunnels.
It follows on from all Elizabeth line stations getting mobile coverage earlier this year.
London’s Transport Commissioner, Andy Lord, said: “It’s wonderful to see our programme to introduce high-speed mobile coverage now benefitting customers on the Elizabeth line.
“This key step in bringing better connectivity to London’s underground stations and tunnels will allow more people travelling around the capital to keep in touch, share photos and make the most of the city, especially as we start to enjoy the summer.”
TfL said the Elizabeth line's tunnelled sections to Whitechapel, Canary Wharf and Woolwich would be connected next, with the whole line completed "by the end of the summer".
The project, implemented by Boldyn Networks, is part of a wider plan to introduce 4G and 5G mobile coverage across the whole Tube, DLR and Elizabeth line network, as well as between Highbury and Islington and New Cross on the London Overground.
Amir Dawoodbhai, 23, who is part of TfL's Youth Panel, says mobile coverage on the Tube and Elizabeth line "enhances" young people's perception of safety as they travel through London independently.
Three UK, EE, Vodafone, and Virgin Media O2 (VMO2) are taking part in the rollout.
TfL said about 500 people work overnight across the Tube network to install mobile equipment, with all works tidied away before the network opens to customers each morning.
Billy D’Arcy of Boldyn Networks said the latest tunnel connections would "benefit a huge number of passengers".