It is not currently possible to use mobile phones underground using native 2G, 3G or 4G networks, and a project to extend coverage before the 2012 Olympics was abandoned because of commercial and technical difficulties.
Saat ini jaringan telepon genggam 2G, 3G atau 4G belum bisa digunakan, dan proyek untuk menambah jangkauan sebelum Olimpiade 2012 akhirnya dibatalkan karena kesulitan dana dan teknis.