Question: What does MTR stand for when speaking of the Guangzhou–Kowloon Through Train's operating system?
Sentence (from "Guangzhou–Kowloon Through Train"): The Guangzhou–Kowloon Through Train () is an inter-city railway service between Hong Kong and Guangzhou jointly operated by the MTR Corporation of Hong Kong and the Ministry of Railways of the People's Republic of China.
Relevant evidence: Yes