Question: Vandalia is a small unincorporated community in Valley County, Montana, established in 1904 with a post office and a store on the Great Northern Railway along the Hi-Line, the Hi-Line is a geographical term referring to the portion of the northern United States south of the Canada–United States border along which runs the main line of which railway?

Context paragraphs:
Vandalia, Montana: Vandalia is a small unincorporated community in Valley County, Montana, United States.  It was established in 1904 with a post office and a store along the Hi-Line of the Great Northern Railway.  The community's chief industry was the manufacture of bricks that were used in public buildings across Montana.  Vandalia also shares its namesake with a local dam on the Milk River that diverts water for the Glasgow Irrigation District.

Fort Saskatchewan station: Fort Saskatchewan station is a former railroad station in Fort Saskatchewan, Alberta, Canada.  It is designated as a heritage site.  It was built by the Canadian Northern Railway along the east-west Canadian Northern Railway line.  The 1 ⁄ -storey, wood-frame building is of a modified third class station design (100-19 plan) employed at some of the major stops along the line; it is longer than that of most third class designs.  This included a vestibule, kitchen, living room, large general waiting room, separate ladies' waiting room, office and a small freight shed and was augmented with an expansion in 1911, In 1986 an agreement was reached by Canadian National and the town to remove the tracks into town and by 1988 the last train passed by the station.  The station building has been restored and is rented out to community groups.

Church Hill, Mississippi: Church Hill is a small unincorporated community in Jefferson County, Mississippi, United States.  It is located on the bluffs of the Mississippi River, approximately 18 miles north of Natchez.  The geographic features are different from those in the rest of the state; there are high and steep bluffs throughout.  At the center intersection of this small community is an old wooden country store, with the old post office in it which was built around 1837.  The store bears the name "Wagner's Grocery" on the upper header of the store.  The store was closed in the late 1990s, after which it was donated to the Church Hill historic society for preservation.  It is the oldest known all-wooden heart pine country store that had a post office in the southeastern United States.

Dearne Valley Railway: The Dearne Valley Railway (DVR) was a railway line which ran through the valley of the River Dearne in South Yorkshire.  It was incorporated by an Act of Parliament on 6 August 1897 to build a line between Brierley Junction, on the main line of the Hull and Barnsley Railway, to junctions with the Great Northern Railway and the Great Northern and Great Eastern Joint Railway south east of Doncaster.

Hi-Line: The Hi-Line is a geographical term referring to the portion of the northern United States south of the Canada–United States border along which runs the main line of the BNSF Railway (originally the mainline of the Great Northern Railway) and U.S. Highway 2.  Specifically, the term most commonly refers to northern Montana, but can also mean the entire region between Spokane, Washington and Minnesota, or even the entire Seattle to Minneapolis route of the BNSF railway.

Wagner, Montana: Wagner is a small, unincorporated village in Phillips County, Montana, USA.  The town lies along the Hi-Line of the Great Northern Railway.

Richland, Montana: Richland is an unincorporated community in Valley County, Montana, United States.  Richland is located in northeast Valley County near the Daniels County line.  The community has a post office with ZIP code 59260.

Sleeman, Ontario: Sleeman is an unincorporated community located in Rainy River District in Northwestern Ontario, Canada.  The town site is located in the center of Dawson.  The original town site was along the Rainy River some 3 km south but in the early 1900s when the steam ships that traveled from Fort Frances to Rainy River and then to Rat Portage Via Lake of the Woods carrying Logs, Lumber, mail and other supplies stopped probably because the Canadian Northern Railway had finished its bridge and rail line from Winnipeg to International Falls and the docks of the great lakes located in Fort William and Port Arthur now known as Thunder Bay the town moved from the river to the rail line.  The original store, coffee shop, post office building still stands today and has been renovated into a home.  The town for many years held many stores, a large hotel, coffee shops, car dealership, school and a busy rail depot that served the Northern communities along Highway 621.  A restaurant called The Green Onion was the local favourite, it was open 7 days a week and held indoor livery stables below for the travels from Morson who came to town to meet the trains, liquor was served here as well.  Today there is only one business left, the Canada Postal outlet.  Lowes Lumber a local business for over 80 years went into bankruptcy and closed its doors in 2014.  Only about 20 homes remain, even though an official town plan was made to accommodate many more.  The rail siding was removed in 1993, the last of the CN hotel burned away in the late 1980s and the grocery store was demolished when the natural gas line was installed to serve the larger communities along Highway 11.

Seiad Valley, California: Seiad Valley is a small unincorporated community in Siskiyou County, California situated 15 miles south of the Oregon border.  A population of approximately 300 people is clustered around the Klamath River, State Route 96, and spread out along the surrounding creeks.  The three craggy peaks of the Lower Devils look over the forested valley, which is completely surrounded on all sides by the green Klamath Mountains, just north of the Marble Mountains Wilderness area.  The Pacific Crest Trail, which runs all the way from Canada to Mexico, passes through the West Side of Seiad Valley.  A general store/cafe/post office, an elementary school, a small trailer park, and the former Wildwood restaurant/inn make up central portion of the town; beyond that are small agricultural/herding fields, a scattering of residences, and the bridges crossing the Klamath River.  Seiad Valley is within zip code 96086, but itself is not incorporated and so has no strictly defined boundaries.

Orienta, Oklahoma: Orienta is a small unincorporated community located at the junction U.S. Highway 60 and U.S. Highway 412 in Major County, Oklahoma.  It lies north of Fairview, east of the Glass Mountains and south of the Cimarron River.  The post office was established March 12, 1901, and took its name from the Kansas City, Mexico and Orient Railway along which it was built,

Supporting paragraphs: Vandalia, Montana Hi-Line
Answer: BNSF Railway