Question: What does MTR stand for when speaking of the Guangzhou–Kowloon Through Train's operating system?

Context paragraphs:
Prince Edward, Hong Kong: Prince Edward is an area in northern Kowloon, Hong Kong.  It is adjacent to the Prince Edward Station of the MTR rapid transit system in Mong Kok.  It is administratively under the Yau Tsim Mong District.  It was named after the namesake road.  It contains the northern end of Nathan Road.  Strictly speaking it is not an area on its own, but the northern part of Mong Kok.  Mong Kok Police Station is right outside the MTR station.

Kowloon-Canton Railway Corporation: The Kowloon-Canton Railway Corporation (KCRC; ) was established in 1982 under the Kowloon-Canton Railway Corporation Ordinance for the purposes of operating the Kowloon–Canton Railway (KCR), and to construct and operate other new railways.  On 2 December 2007, the MTR Corporation Limited, another railway operator in Hong Kong, took over the operation of the KCR network under a 50-year service concession agreement, which can be extended.  Under the service concession, KCRC retains ownership of the KCR network with the MTR Corporation Limited making annual payments to KCRC for the right to operate the network.  The KCRC is wholly owned by the Government of Hong Kong and its activities are governed by the KCRC Ordinance as amended in 2007 by the Rail Merger Ordinance to enable the service concession agreement to be entered into with the MTR Corporation Limited.

OS/360 Object File Format: The OS/360 Object File Format is the standard object module file format for the IBM DOS/360, OS/360 and VM/370, Univac VS/9, and Fujitsu BS2000 mainframe operating systems.  In the 1990s, the format was given an extension with the XSD-type record for the MVS Operating System to support longer module names in the C Programming Language.  This format is still in use by the z/VSE operating system (the follow-on to the DOS/360 Operating System).  In contrast, it has been superseded by the GOFF file format on the MVS Operating System (the follow-on to the OS/360 Operating System) and on the z/VM Operating System (the follow-on to the VM/370 Operating System).  Since the MVS and z/VM loaders will still handle this older format, some compilers have chosen to continue to produce this format instead of the newer GOFF format.

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.  Services operate along the East Rail Line within Hong Kong territory, crossing the Hong Kong-Chinese border at Lo Wu, and continuing along the Guangmao Railway and Guangshen Railway in Guangdong province.

MS-DOS: MS-DOS ( ; acronym for "Microsoft Disk Operating System") is a discontinued operating system for x86-based personal computers mostly developed by Microsoft.  Collectively, MS-DOS, its rebranding as IBM PC DOS, and some operating systems attempting to be compatible with MS-DOS, are sometimes referred to as "DOS" (which is also the generic acronym for disk operating system).  MS-DOS was the main operating system for IBM PC compatible personal computers during the 1980s and the early 1990s, when it was gradually superseded by operating systems offering a graphical user interface (GUI), in various generations of the graphical Microsoft Windows operating system.

MTR Corporation: MTR Corporation Limited () is a Hong Kong company listed on the Hong Kong Exchange, and a component of Hang Seng Index.  MTR runs Hong Kong's Mass Transit Railway (MTR), and is also a major property developer and landlord in Hong Kong.  It also invests in railways in different parts in the world, and has obtained contracts to operate rapid transit systems in London, Stockholm, Beijing, Shenzhen, Hangzhou, Melbourne, and Sydney.

H1droid: The H1droid project started when Vodafone sold Samsung H1 mobile phones running on LiMo operating system.  Mobile phones running with the LiMO operating system were so few that only a few applications were also available.  With this limitation, Samsung H1 owners wanted to run the phone with the more famous Android operating system since the phone itself had good hardware attributes.  LiMo operating system also shared other characteristics as Android which could be a good platform for operating system transformation.  With this idea, a group of software enthusiast shared ideas on blogsites from all over the world and developed the H1droid and distributed it on the Internet.  The software is still on the development stage with a few bugs and it is ongoing.

Common stored value ticket: A common stored value ticket was a plastic magnetically sensitive card used for paying fares on the MTR and KCR railway systems in Hong Kong from 1984 to 1999.  It was also used on Citybus and Kowloon Motor Bus for some MTR and KCR feeder bus services.  The system was replaced by the Octopus card system in 1997 and phased out on 2 January 1999.  The MTR and KCR have continued to issue magnetic strip cards for single-journey and souvenir tickets.

Disk operating system: A disk operating system (abbreviated DOS) is a computer operating system that can use a disk storage device, such as a floppy disk, hard disk drive, or optical disc.  A disk operating system must provide a file system for organizing, reading, and writing files on the storage disk.  Strictly speaking, this definition does not apply to current generations of operating systems, such as versions of Microsoft Windows in use, and is more appropriately used only for older generations of operating systems.

TempleOS: TempleOS (formerly J Operating System, SparrowOS and LoseThos) is a biblical-themed lightweight operating system created over the span of a decade by the American programmer Terry A. Davis.  The software is a x86-64 bit, multi-tasking, multi-cored, public domain, open source, ring-0-only, single address space, non-networked, PC operating system for recreational programming.  The operating system was designed to be the Third Temple according to Davis and uses an interface similar to a mixture of DOS and Turbo C.  Davis describes the operating system as a modern x86-64 Commodore 64 with a variation of C (named HolyC) in place of BASIC.

Supporting paragraphs: Guangzhou–Kowloon Through Train MTR Corporation
Answer: Mass Transit Railway