Nexus say passengers will have to wait a little longer for 4G access on the Metro.
The rail operator previously said customers would be able to access high speed internet on trains by autumn.
But the work is behind schedule and it is now slated to last until the end of the year.
At the moment, passengers can only access 2G connection while in tunnels and stations.
Engineers are in the process of boosting that to 4G, meaning passengers will be able to stream videos and music even when they are underground.
A Nexus spokesman said: “The installation of 4G internet connectivity in the Metro tunnels and its underground stations remains ongoing.
“One mobile network operator, EE, has commenced work to upgrade their signal to 4G, work is ongoing and we expect this to be completed by the end of the year.
“We hope the other mobile operators will also follow in due course.
“Tyne and Wear Metro was the first in the UK to provide passengers with mobile phone connections in tunnels and underground stations.
"We are now in the process of upgrading from the current 2G signal to 4G, allowing people to stream content to smart phones and tablets.”
