The Mountain Subdivision is a railroad line owned and operated by CSX Transportation

CSX Transportation

CSX Transportation operates a Class I railroad in the United States known as the CSX Railroad. It is the main subsidiary of the CSX Corporation. The company is headquartered in Jacksonville, Florida, and owns approximately 21,000 route miles...

 in the U.S. state

U.S. state

A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

s of Maryland

Maryland

Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...

 and West Virginia

West Virginia

West Virginia is a state in the Appalachian and Southeastern regions of the United States, bordered by Virginia to the southeast, Kentucky to the southwest, Ohio to the northwest, Pennsylvania to the northeast and Maryland to the east...

. The line runs from Cumberland, Maryland

Cumberland, Maryland

Cumberland is a city in the far western, Appalachian portion of Maryland, United States. It is the county seat of Allegany County, and the primary city of the Cumberland, MD-WV Metropolitan Statistical Area. At the 2010 census, the city had a population of 20,859, and the metropolitan area had a...

 west to Grafton, West Virginia

Grafton, West Virginia

Grafton is a city in, and county seat of, Taylor County, West Virginia, USA. The population was 5,489 at the 2000 census. The only two national cemeteries in West Virginia are located in Grafton. Mother's Day was founded in Grafton on May 10, 1908; the city is the home to the International Mother's...

 along the original Baltimore and Ohio Rail Road (B&O) main line. It was known as the West End Subdivision until the B&O's absorption into the Chessie System

Chessie System

Chessie System, Inc. was a holding company that owned the Chesapeake and Ohio Railway , the Baltimore and Ohio Railroad , the Western Maryland Railway , and several smaller carriers. It was incorporated in Virginia on February 26, 1973, and it acquired the C&O on June 15...

, and included the B&O's original crossing of the Allegheny Mountains

Allegheny Mountains

The Allegheny Mountain Range , also spelled Alleghany, Allegany and, informally, the Alleghenies, is part of the vast Appalachian Mountain Range of the eastern United States and Canada...

. Through CSX traffic to the west from Cumberland now uses the Keystone Subdivision

Keystone Subdivision

The Keystone Subdivision is a railroad line owned and operated by CSX Transportation in the U.S. states of Maryland and Pennsylvania. The line runs from Cumberland, Maryland west to McKeesport, Pennsylvania along a former Baltimore and Ohio Railroad line...

 over Sand Patch Grade

Sand Patch Grade

Sand Patch Grade is a ~100 mile length of railroad track known for its steep grades and curves through the Allegheny Mountains of Pennsylvania and Maryland. The line is part of the Keystone Subdivision, an East-West main line operated by CSX Transportation...

.

At its east end, the Mountain Subdivision becomes the Cumberland Terminal Subdivision

Cumberland Terminal Subdivision

The Cumberland Terminal Subdivision is a railroad line owned and operated by CSX Transportation in the Cumberland, Maryland area. The line centers around the Cumberland rail yard and is a junction with three other subdivisions....

 at Beall Street. It junctions the Thomas Subdivision twice - near Keyser, West Virginia

Keyser, West Virginia

Keyser is a city in and the county seat of Mineral County, West Virginia, United States. It is part of the Cumberland, MD-WV Metropolitan Statistical Area. The population was 5,303 at the 2000 census.- History :...

 and near Piedmont, West Virginia

Piedmont, West Virginia

Piedmont is a town in Mineral County, West Virginia, United States. It is part of the 'Cumberland, MD-WV Metropolitan Statistical Area'. The population was 1,014 at the 2000 census. Piedmont was chartered in 1856...

 - and meets the Fairmont Subdivision

Fairmont Subdivision

The Fairmont Subdivision is a railroad line owned and operated by CSX Transportation in the U.S. state of West Virginia. The line runs from Grafton northwest to Rivesville along the old Baltimore and Ohio Rail Road main line and a former branch of it....

 near its west end at Grafton. At its west end, it continues as the Bridgeport Subdivision

Bridgeport Subdivision

The Bridgeport Subdivision is a railroad line owned and operated by CSX Transportation in the U.S. state of West Virginia. The line runs from Grafton west to Clarksburg along a former Baltimore and Ohio Rail Road line...

. The Mountain Subdivision's summit is at Altamont, Maryland

Altamont, Maryland

Altamont is an unincorporated community in Garrett County, Maryland, United States. Altamont sits on the Eastern Continental Divide between the watershed of Crabtree Creek, which flows into the Savage River and eventually into the Atlantic Ocean, and the watershed of the Little Youghiogheny River,...

, at the west end of the Seventeen Mile Grade; the grade's east end is at Piedmont, West Virginia

Piedmont, West Virginia

Piedmont is a town in Mineral County, West Virginia, United States. It is part of the 'Cumberland, MD-WV Metropolitan Statistical Area'. The population was 1,014 at the 2000 census. Piedmont was chartered in 1856...

.

History

The Mountain Subdivision was opened in 1852 as part of the B&O's main line. In 1904 the B&O built the Patterson Creek Cutoff

Patterson Creek Cutoff

The Patterson Creek Cutoff is an abandoned railroad line built by the Baltimore and Ohio Railroad in northern West Virginia and Western Maryland, that served trains running on the B&O "West End" line in the Cumberland, Maryland area...

 to alleviate congestion in its Cumberland rail yard

Rail yard

A rail yard, or railroad yard, is a complex series of railroad tracks for storing, sorting, or loading/unloading, railroad cars and/or locomotives. Railroad yards have many tracks in parallel for keeping rolling stock stored off the mainline, so that they do not obstruct the flow of traffic....

. The cutoff line ran from McKenzie, Maryland

McKenzie, Maryland

McKenzie is an unincorporated community in Allegany County, Maryland, containing only a few houses, and mostly land. Its name is derived from a family which owned a large farm along the river bottom in the area. It is directly across from the Allegany Ballistics Laboratory in Rocket Center, West...

 to Patterson Creek, West Virginia

Patterson Creek, West Virginia

Patterson Creek is an unincorporated community in Mineral County, West Virginia, USA. It lies at the northeastern end of the county, and is named for Patterson Creek which empties into the North Branch Potomac River here....

, providing a bypass of the yard for coal trains moving between Keyser and Brunswick, Maryland

Brunswick, Maryland

Brunswick is a city in Frederick County, Maryland, United States. The population was 5,870 at the 2010 census.- History :The area now known as Brunswick was originally home to the Susquehanna Indians. In 1728 the first settlement was built, and the region became known as Eel Town, because the...

.

During the 1970s ownership of the subdivision passed from the B&O to the Chessie System, which closed the Patterson Creek Cutoff. Chessie was merged into CSX in the early 1980s.