Question: Which company operates the railway line that bounds Peterhead, South Australia on the west side?

Context paragraphs:
KTM East Coast Railway Line: The East Coast Railway Line is the single track metre gauge runs between Gemas railway station, in Negeri Sembilan and Tumpat railway station, in Kelantan of Malaysia.  Gemas is the rail junction between the West Coast line and East Coast railway line.  Like the West Coast Railway Line, it is called the East Coast Railway Line (Malaysia) because it serves two of Peninsular Malaysia's East Coast states, namely Pahang and Kelantan.  In fact, it does not run along the coast at all and only meets the South China Sea when it terminates in Tumpat railway station.  It runs through the interior, often through deep jungle, thus earning the nickname Jungle Railway.  Terengganu is the only state in Peninsular Malaysia not served by the KTM railway network.

Aichi Loop Line: The Aichi Loop Line (愛知環状鉄道線 , Aichi Kanjō Tetsudō-sen , "Aichi Loop Railway Line") is a Japanese railway line connecting Okazaki Station in Okazaki and Kōzōji Station in Kasugai, operated by the Aichi Loop Railway (愛知環状鉄道 , Aichi Kanjō Tetsudō ) .  The company or the line is abbreviated as Aikan (愛環 ) .  This is the only line the company operates.  Despite its name, the line is not a true loop, but a north-south line situated east of Nagoya, which can be considered as an unclosed loop.

Carlingford railway line: The Carlingford railway line is a minor railway line in Sydney, Australia.  Opened in 1888, the line runs north-south between the suburb of Carlingford and the Main Suburban railway line at .  Passenger services on the line form part of the Sydney Trains commuter rail network and are marketed as the T6 Carlingford Line.  The railway line's small catchment, low patronage, short platforms and single track for much of its length mean the T6 generally operates as a shuttle service, with passengers changing at Clyde for T1 North Shore, Northern & Western Line services to the Sydney central business district and Parramatta.  Most of the line is planned for conversion to light rail as part of the Parramatta Light Rail network.  As a result, the line will permanently close.

Peterhead, South Australia: Peterhead is a north-western suburb of Adelaide 15 km from the CBD, on the LeFevre Peninsula, in the state of South Australia, Australia and falls under the City of Port Adelaide Enfield.  It is adjacent to Largs Bay and Birkenhead.  The postcode for Peterhead is 5016.  It is bounded to the north by Wills Street, to the south by Hargrave Street and in the west and east by the Outer Harbor railway line and the Port River respectively.

Akita Rinkai Railway Line: The Akita Rinkai Railway Line (秋田臨海鉄道線 , Akita Rinkai Tetsudō-sen ) is a Japanese freight-only railway line between Akita Kitakō Freight Terminal and Mukaihama Freight Terminal via Akitakō Freight Terminal, all within Akita, Akita.  This is the only railway line Akita Rinkai Railway (秋田臨海鉄道 , Akita Rinkai Tetsudō , "Akita Seaside Railway") operates.  The third sector company was founded in 1970.  The services on the line are divided by Akitakō Station.  The north part is commonly called the North Line (北線 , Kita-sen ) , and the south part is called the South Line (南線 , Minami-sen ) .  The North Line mainly transports containers of paper products from Tōhoku, while the South Line transports sulfuric acid from Kosaka Smelting & Refining, via the Kosaka Line.

Outer Harbor railway line: The Outer Harbor railway line is a suburban branch line in Adelaide, South Australia.  It runs from Adelaide station through the north western suburbs to Port Adelaide and Outer Harbor.  It is 21.9 kilometres in length, and shares part of its run with the Grange line.  It is operated by Adelaide Metro.

Birkenhead, South Australia: Birkenhead is a north-western suburb of Adelaide 14 km from the CBD, on the Lefevre Peninsula, in the state of South Australia, Australia, and lies within the City of Port Adelaide Enfield.  It is adjacent to Peterhead, Exeter and Glanville.  It is bounded to the south by the Gawler Reach of the Port River, to the north by Hargrave Street and in the west and east by the Outer Harbor railway line and the Port River respectively.

Nishikigawa Seiryū Line: The Nishikigawa Seiryū Line (錦川清流線 , Nishikigawa Seiryū-sen , "Nishiki River Limpid Stream Line") is a Japanese railway line connecting Kawanishi and Nishikichō stations, all within Iwakuni, Yamaguchi.  As the name suggests, the line parallels the Nishiki River ("Nishiki-gawa").  This is the only railway line Nishikigawa Railway (錦川鉄道 , Nishikigawa Tetsudō ) operates.  The third-sector company (in Japanese sense) took former West Japan Railway Company (JR West) line in 1987.  The line was proposed to be extended to Nichihara, on the Yamaguchi Line, but was not completed (see History section below).  The company also operates bus lines and a travel agency.

Toyama Chihō Railway: The Toyama Chihō Railway (富山地方鉄道 , Toyama Chihō Tetsudō , "Toyama Regional Railway") is a transportation company in Toyama, Toyama Prefecture, Japan.  The company is commonly known as Chitetsu (地鉄 ) .  The private company operates railway, tram, and bus services in the eastern part of the prefecture.  It also operates as the agency of All Nippon Airways in Toyama area.  The company has its root in Toyama Electric Railway (富山電気鉄道 , Toyama Denki Tetsudō ) founded in 1930.  The current company was founded in 1943, when all the private and public operators of railway, tram, and bus lines in the prefecture were merged into one.  In 1950, it founded Kaetsunō Railway, planning to build the railway line that links Toyama and Ishikawa.  Chitetsu handed over its networks in the western part of Toyama Prefecture, although the plan never came into reality.

Yanco–Griffith railway line: The Yanco to Griffith railway line is a railway line in New South Wales, Australia.  Together with the Junee- Yanco section of the Hay railway line, it is one of two routes to the town of Griffith, the other route being via Temora.  It branches from the Hay railway line at the town of Yanco and passes through the town of Leeton before reaching Griffith.  The line is open to passenger trains - a weekly NSW TrainLink passenger service operates on weekends.  A passenger station remains open at Leeton.

Supporting paragraphs: Peterhead, South Australia Outer Harbor railway line
Answer: Adelaide Metro