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17-Mile Grade: B&O Tackles The Alleghenies

Published: February 4, 2025

By: Adam Burns

17-Mile Grade is a historically significant section of the Baltimore and Ohio Railroad (B&O), a pioneering company established in the early 19th century.

As the first common carrier, the B&O played a critical role in the nation's industrial progress.  During its attempt to reach the Ohio River the railroad was blocked by Pennsylvania from laying tracks within its state.  

As a result, it was forced to engineer a line along Maryland's rugged Potomac River Valley and then-Northwestern Virginia.  As part of the B&O's so-called "West End" this stretch of railroad was always extremely difficult, and remains so today under CSX.

17-Mile presents a remarkable example of early railroad engineering endeavors, showcasing the challenges of traversing the Appalachian Mountains and the ingenuity required to overcome these obstacles.

A B&O company photo showcasing EM-1 #7611 on 17-Mile Grade at Altamont, Maryland, circa 1940s.

Early Development of the B&O

The Baltimore and Ohio Railroad was chartered on February 28, 1827, with the intention of improving the transportation of goods and people to the American West.

At a time when canals were the predominant means of transport, the B&O Railroad offered a visionary alternative, aiming to connect the bustling port city of Baltimore to the Ohio River.

The construction of the railroad began on July 4, 1828, and the first 13 miles were completed by 1830, extending from Baltimore to Ellicott's Mills, Maryland.

Engineering Challenges: Navigating the Appalachian Mountains

The B&O Railroad faced numerous engineering challenges, one of the most formidable being the Appalachian Mountains. The construction of the 17-Mile Grade exemplifies the complexities of building a railroad through this rugged terrain.

The line, aptly named for its 17-mile stretch, extends from Altamont's summit down to the town of Piedmont at the base of Backbone Mountain. With most freight moves eastward to Cumberland, necessitating a descent of Backbone Mountain, which is notoriously one of the most treacherous downhill grades on the Eastern Seaboard. 

Historically, to the north of the current dual tracks, a substantial wye facilitated the turning of steam engines until the 1950s, when the shift to diesel engines rendered this maneuver unnecessary, leaving only its western leg.

The section of the Mountain Subdivision to the east of Altamont was once equipped with four tracks: two main lines, a passing siding between AM Tower and Wilson, and a six-mile third main track extending from "AM" Tower to the former "HX" Tower at Strecker.

The reduction in traffic eventually led to the removal of the third main track in the early 1970s, while the passing siding remained operational until the closure of the Altamont tower in the 1990s, resulting in the retention of only the two primary main tracks.

Grades over the line are very steep for main line railroading, ranging from 1.7%-2.5%.

Locomotives Tackling the 17-Mile Grade

17-Mile Grade required locomotives with extraordinary power and stamina. In the early years, horses and rudimentary steam engines were used, but they struggled with the incline and curvature of the tracks.

The solution came in the form of the "Camelback" locomotives, designed by Ross Winans in the mid-19th century. These powerful steam engines featured an elevated cab that straddled the boiler, providing improved visibility for engineers as well as enhanced traction and the ability to pull heavier loads up the steep grade.

The advancement of locomotive technology, with improvements to steam engines and later diesel engines, enabled the B&O Railroad to maintain its efficiency and reliability in traversing the Appalachian Mountains.

As another technological leap, the Mallet articulated locomotives were introduced in the early 20th century, offering even greater power and flexibility to tackle arduous climbs like the 17-Mile Grade.

Economic Impact and Legacy

The successful navigation of the 17-Mile Grade was a testament to the pioneering spirit of early railroad engineers and a crucial factor in the economic development of the region.

By overcoming the barrier of the Appalachian Mountains, the B&O Railroad facilitated the movement of freight and passengers from the eastern seaboard to the American Midwest.

This connectivity played a pivotal role in the establishment of commerce, the spread of industrialization, and the diffusion of cultural influences across state boundaries.

The 17-Mile Grade, as part of the B&O Railroad, contributed to the transformation of small towns into burgeoning industrial centers. Cities such as Cumberland, Maryland, flourished as railroad hubs, benefiting from increased trade, jobs, and economic prospects.

Moreover, the B&O's achievement laid the groundwork for subsequent railroads to navigate similar geographic obstacles, fostering nationwide infrastructure development.

A Legacy of Engineering Triumph

17-Mile Grade represents a significant chapter in the history of American transportation. By conquering the challenges posed by the Appalachian Mountains, the B&O Railroad demonstrated the power of engineering and perseverance, leaving an enduring legacy for the burgeoning industrial nation. The Grade remains a symbol of industrial ingenuity, a monument to the determination and foresight of those who built the foundations of America’s rail network. As we reflect on the historical significance of this engineering feat, the 17-Mile Grade reminds us of the enduring impact of innovative solutions in overcoming the natural obstacles that define both our geography and our ambition.