What is Zizang then? 

An anonymous contributor on ipaddress 81.229.147.109 changed a section the explanation of the railways name from:

 The line is named after its termini, Xizang being a phonetic transcription of the name for Tibet in Putonghua

to

 The line is named after its termini, Xizang, which is the name for Tibet in Putonghua.

The second is certainly wrong, as Zizang is a piece of written text in a latin alphabet, wheras Putonghua is a spoken language only, with no way of being represented in a latin alphabet without some form of transcription. Anybody know a better way of putting this.