Mass Rapid Transit Act Article 8

In order to facilitate mass rapid transit system communications, the organization of construction or operation of mass rapid transit system may establish the exclusive mass rapid transit system telecommunications after obtaining approval from the Ministry of Transportation and Communications.
中文原文 大眾捷運法第8條
為謀大眾捷運系統通信便利,大眾捷運系統工程建設或營運機構,經交通部核准,得設置大眾捷運系統專用電信。

English translation for reference only; the Chinese text prevails. Not legal advice.