Question: which American Class I railroad was White Horse, formally located 

Context paragraphs:
Uffington White Horse: The Uffington White Horse is a highly stylised prehistoric hill figure, 110 m long, formed from deep trenches filled with crushed white chalk.  The figure is situated on the upper slopes of White Horse Hill in the English civil parish of Uffington (in the ceremonial county of Oxfordshire, historic county of Berkshire), some 8 km south of the town of Faringdon and a similar distance west of the town of Wantage; or 2.5 km south of Uffington.  The hill forms a part of the scarp of the Berkshire Downs and overlooks the Vale of White Horse to the north.  The best views of the figure are obtained from the air, or from directly across the Vale, particularly around the villages of Great Coxwell, Longcot and Fernham.  The site is owned and managed by the National Trust and is a Scheduled Ancient Monument. " The Guardian" stated in 2003 that "for more than 3,000 years, the Uffington White Horse has been jealously guarded as a masterpiece of minimalist art."  It has also inspired the creation of other white horse hill figures.

Great Northern Railway (U.S.): The Great Northern Railway (reporting mark GN) was an American Class I railroad.  Running from Saint Paul, Minnesota, to Seattle, Washington, it was the creation of 19th-century railroad entrepreneur James J. Hill and was developed from the Saint Paul & Pacific Railroad.  The Great Northern's (GN) route was the northernmost transcontinental railroad route in the U.S.

Devizes White Horse: The Devizes White Horse, officially known as the Devizes Millennium White Horse, is a hill figure of a horse located on Bank Field, an escarpment at Roundway Hill, on the outskirts of the town of Devizes above the hamlet of Roundway, Wiltshire, England; it is about ½ mile north of Roundway.  It was cut in 1999 to celebrate the forthcoming third millennium, and is based on a design of another white horse hill figure, which was also known as the Devizes White Horse, or sometimes The Snobs Horse, which was very close to the present horse as it was also on Roundway Hill beneath the Oliver's Castle hill fort.  Traces of the Snobs Horse can still be seen under the right conditions.

White Horse Historic District: White Horse Historic District, also known as White Horse Village, is a national historic district located in Willistown Township, Chester County, Pennsylvania.  It encompasses 15 contributing buildings and 1 contributing structure in the crossroads village of White Horse.  They were built between 1798 and about 1950 and are mostly 2 1/2 or 3-story masonry structures clad in stucco.  Seven of the contributing buildings are residences.  The other contributing buildings include the former blacksmith shop (c. 1812 / 1848), (Thomas J. Thornton from Dundalk Ireland was the resident blacksmith from 1948 until his death while shoeing a horse at nearby Radnor Hunt on April 13, 1968), White Horse Store and residence (1798), and White Horse Tavern (c. 1798).  A number of the houses were renovated in the 1930s and 1940s by noted architect R. Brognard Okie (1875-1945).

White Horse Tavern, Cambridge: The 'White Horse Tavern' or 'White Horse Inn' was allegedly the meeting place in Cambridge for English Protestant reformers to discuss Lutheran ideas, from 1521 onwards.  According to the historian Geoffrey Elton the group of university dons who met there were nicknamed 'Little Germany' in reference to their discussions of Luther.  Whilst the pub undoubtedly existed, several scholars have questioned the existence of the 'White Horse' meetings - they are described by John Foxe in his Book of Martyrs, but no other evidence for them exists.  Gergely M Juhász writes that 'Foxe’s romantic image of these students and scholars convening secretly on a regular basis in the White Horse Inn… is unsubstantiated', and Alec Ryrie refers to it as 'the stubborn legend of the White Horse Inn.'

Hackpen White Horse: Hackpen White Horse is a chalk hill figure of a white horse on Hackpen Hill, located below The Ridgeway on the edge of the Marlborough Downs, two miles south east of Broad Hinton, Wiltshire, England.  It is one of nine white horse hill figures located in Wiltshire.  It is also known as the Broad Hinton White Horse due to its near location to Broad Hinton.  Supposedly cut by local parish clerk Henry Eatwell in 1838 to commemorate the coronation of Queen Victoria, the horse is 90' square feet and is said to be best viewed from B4041 road.  The horse is regularly scoured and maintained.

Cherhill White Horse: The Cherhill White Horse is a hill figure on Cherhill Down, 3.5 miles east of Calne in Wiltshire, England.  Dating from the late 18th century, it is the third oldest of several such white horses in Great Britain, with only the Uffington White Horse and the Westbury White Horse being older.  The figure is also sometimes called the Oldbury White Horse.

White Horse, California: White Horse (also, Whitehorse and Kinyon) is an unincorporated community in Modoc County, California.  It is located on the former Great Northern Railway Hambone Line, off the Bieber Line, that connected with the McCloud River Railroad.  25 mi west-northwest of Adin, 0.7 miles (1.1 km) east of Whitehorse Flat Reservoir and 47 mi west-southwest of Alturas, at an elevation of 4423 feet (1348 m).

Alton Barnes White Horse: Alton Barnes White Horse is a chalk hill figure of a white horse located on Milk Hill some 1,000 metres north of the village of Alton, Wiltshire, England.  The horse is approximately 180 feet high and 160 feet long, and was cut in 1812 under the commission of local farmer Robert Pile.  Pile instructed inn sign painter John Thorne to design and cut the horse, although Thorne conned Pile by leaving with his advance sum while employing local resident John Harvey to cut the horse instead.  It is based on another white horse hill figure in Wiltshire, the Cherhill White Horse, and is the second-biggest of nine white horses in Wiltshire.

Old White Horse Cellar: The Old White Horse Cellar also known as Hatchetts White Horse Cellar at No. 155 Piccadilly, was one of the best known coaching inns in England during the 18th and 19th centuries.  The first mention of the White Horse Cellar is in 1720.  It was originally located on the corner of Arlington Street, where the Ritz Hotel is now located.  The first landlord, a man named Williams, named it in honor of the newly established House of Hanover, whose heraldic emblem featured a white horse.  The White Horse rose to prominence under Abraham Hatchett who later moved it to the opposite side of the road on the corner of Albemarle Street, where it was known as "Hatchett’s Hotel and White Horse Cellar".  The precise date of the move is not known, but was precipitated by the construction of the Bath Hotel, which was located on the corner of Piccadilly and Arlington as early as 1798.  It was torn down in 1884 to make room for the Albemarle.

Supporting paragraphs: White Horse, California Great Northern Railway (U.S.)
Answer: The Great Northern Railway