Hypernet is already underground

From March 2012, 23, Hipernet became available to Telenor's customers on the entire metro network of Budapest. 

Telenor completed the terrestrial part of its network development at the end of 2011, making it the most extensive and one of the highest theoretical download speed 3G mobile internet networks available to its customers. The service provider's plans for 2012 include fine-tuning, connecting new areas to the 3G network and increasing indoor coverage. HÉV provides mobile internet with a theoretical download speed of 23 Mbps on its underground sections and at all their stops. With this step, Telenor has achieved another very important goal: to provide its customers with the experience of seamless mobile internet in even more places. 
The spread of mobile broadband is well illustrated by the fact that in order to obtain information quickly, more than 60 percent of Telenor's customers use the Internet several times a day on their mobile phones, which they can now do on Metro 1, 2 and 3. As a result of network development, the company is able to reliably serve the ever-increasing capacity needs.

“In the metro tunnel, a special solution is needed to ensure adequate coverage: so-called broadcast cables can be used to guarantee a more even field strength. Thus, immediately after Telenor gained access to this network infrastructure, it began building the right-of-bandwidth application network to offer our customers the same speed and reliability on the ground as we do across the country. ” - said Zsolt Sepsi, Telenor's Acting Deputy Chief Technical Officer.

From mid-March, for example, Telenor subscribers traveling on the red metro will be able to watch a 7-minute video from YouTube without a hitch, until they reach the Örs vezér tere terminus from Keleti Railway Station. In this, the cell boundaries should not disturb the netizens either, because Telenor has even installed a special station for several stops, so video downloading and browsing (in the best case scenario) are not interrupted for a moment.

Source: telenor.hu