According to Beijing MTR Corporation, operator of Beijing subway line 4, it has entered into an agreement with China Mobile Beijing to bring the company's mobile phone signal into the subway's line 4.
Under the agreement, from the opening date of the subway line 4, China Mobile's mobile phone signal, including the TD-SCDMA signal, will be [...]

He Ning, general manager of China Mobile Beijing branch, told local media that the company has still not reached an agreement with the Beijing Subway authorities on the allowing mobile phone signlas in the newly-built Line 10 subway.