The Baltimore and Potomac Tunnel (or B&P Tunnel) is a

double-tracked Double tracking or doubling is an audio recording technique in which a performer sings or plays along with their own prerecorded performance, usually to produce a stronger or bigger sound than can be obtained with a single voice or instrument. ...

, masonry arch railroad

tunnel A tunnel is an underground passageway, dug through surrounding soil, earth or rock, and enclosed except for the entrance and exit, commonly at each end. A pipeline is not a tunnel, though some recent tunnels have used immersed tube cons ...

on the

Northeast Corridor The Northeast Corridor (NEC) is an electrified railroad line in the Northeast megalopolis of the United States. Owned primarily by Amtrak, it runs from Boston through Providence, New Haven, Stamford, New York City, Philadelphia, Wilmington, a ...

Baltimore, Maryland Baltimore ( , locally: or ) is the List of municipalities in Maryland, most populous city in the U.S. state of Maryland, fourth most populous city in the Mid-Atlantic (United States), Mid-Atlantic, and List of United States cities by popula ...

, just south of

Pennsylvania Station Pennsylvania Station (often abbreviated Penn Station) is a name applied by the Pennsylvania Railroad (PRR) to several of its grand passenger terminals. Several are still in active use by Amtrak and other transportation services; others have been ...

. Opened in 1873, the tunnel is used by about 140

Amtrak The National Railroad Passenger Corporation, Trade name, doing business as Amtrak () , is the national Passenger train, passenger railroad company of the United States. It operates inter-city rail service in 46 of the 48 contiguous United Stat ...

and

MARC Marc or MARC may refer to: People * Marc (given name), people with the first name * Marc (surname), people with the family name Acronyms * MARC standards, a data format used for library cataloging, * MARC Train, a regional commuter rail system o ...

passenger trains and two freight trains every day, as of 2008. The tunnel, which passes under the Baltimore neighborhoods of Bolton Hill, Madison Park, and Upton, consists of three tunnels —Gilmor Street Tunnel, Wilson Street Tunnel, and John Street Tunnel—separated by two open-air cuts: Pennsylvania Avenue Opening and John Street Opening.

History and operations

Constructed by the

Baltimore and Potomac Railroad The Baltimore and Potomac Railroad (B&P) operated from Baltimore, Maryland, southwest to Washington, D.C., from 1872 to 1902. Controlled by the Pennsylvania Railroad, it was the second railroad company to connect the nation's capital to the Nor ...

under Winchester Street and Wilson Street in Baltimore, the tunnel opened on June 29, 1873. The B&P tunnel allowed the

Pennsylvania Railroad The Pennsylvania Railroad (reporting mark PRR), legal name The Pennsylvania Railroad Company also known as the "Pennsy", was an American Class I railroad that was established in 1846 and headquartered in Philadelphia, Pennsylvania. It was named ...

(PRR) direct access to

Washington, D.C. ) , image_skyline = , image_caption = Clockwise from top left: the Washington Monument and Lincoln Memorial on the National Mall, United States Capitol, Logan Circle, Jefferson Memorial, White House, Adams Morgan, ...

, for the first time by connecting its

Northern Central Railway The Northern Central Railway (NCRY) was a Class I Railroad connecting Baltimore, Maryland with Sunbury, Pennsylvania, along the Susquehanna River. Completed in 1858, the line came under the control of the Pennsylvania Railroad (PRR) in 1861, wh ...

affiliate (which arrived in Baltimore from the north) to the Baltimore and Potomac's new spur, which ran to Washington. Between 1916 and 1917, the PRR expanded the tunnel to accommodate larger trains. The railroad lowered the floor of the tunnel about feet, underpinned the side walls, installed a concrete invert slab, and rebuilt the track structure. The bases of the tunnel walls were chipped away to improve horizontal clearance. Before the PRR

electrified Electrification is the process of powering by electricity and, in many contexts, the introduction of such power by changing over from an earlier power source. The broad meaning of the term, such as in the history of technology, economic history ...

its

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-to-Washington main line in 1935, the poorly ventilated tunnel filled with smoke from steam locomotives. The smoke also was a nuisance to the residential neighborhoods above the tunnel. In preparation for electrified operation, the tunnel was lined with gunite to waterproof the arch and prevent icicles from shorting out the catenary wires. Financial considerations prevented the PRR from constructing a new passenger tunnel on the Presstman Street alignment, for which it previously had acquired rights. The PRR's plan had envisioned using the new Presstman Street tunnel and the original bores of the

Union Tunnel The Union Tunnel is a railroad tunnel on Amtrak's Northeast Corridor in Baltimore, Maryland adjacent to Pennsylvania Station that was built to connect the Pennsylvania Railroad's original mainline to Philadelphia, Pennsylvania and points north. T ...

for passenger operations, while the old B&P Tunnel and the newer bores of the Union Tunnel (completed in the 1930s) would have been used for freight operations. In the late 1950s, the tunnel became a hindrance to the growth of PRR's Trailer-on-Train service, which required additional vertical and horizontal clearance to accommodate

semi-trailer A semi-trailer is a trailer without a front axle. In the United States, the term is also used to refer to the combination of a truck and a semi-trailer; a tractor-trailer. A large proportion of a semi-trailer's weight is supported by a trac ...

s on top of railroad

flatcar A flatcar (US) (also flat car, or flatbed) is a piece of rolling stock that consists of an open, flat deck mounted on a pair of trucks (US) or bogies (UK), one at each end containing four or six wheels. Occasionally, flat cars designed to carry ...

s. The curve at Pennsylvania Avenue was the biggest constraint. The PRR modified the tunnel walls and ceiling for a distance of to improve clearance and enable high cars and piggyback trailers to traverse the tunnel without damaging their roofs. Additionally, a

gauntlet track Gauntlet track or interlaced track (also gantlet track) is an arrangement in which railway tracks run parallel on a single track bed and are interlaced (i.e., overlapped) in such a way that only one pair of rails can be used at any time. Since th ...

was installed on southbound Track 3 to route trains closer to the middle of the tunnel. However, the gauntlet track effectively created a single-track tunnel. No trains could run on Track 2 while the gauntlet was in use; a broken-down train on the gauntlet closed the tunnel to traffic until it could be moved. Even with the gauntlet, cars that were taller than or with a loading gauge in excess o
Plate C
could not use the tunnel. In the early 1980s, the tunnel underwent rehabilitation as part of the Northeast Corridor Improvement Project. The repairs included replacing the existing invert, repairing the tunnel lining, upgrading the track structure, installing a new gauntlet track, and rehabilitating the tunnel drainage system. No fundamental change was made in the tunnel's difficult geometry. Eventually, the gauntlet track was removed due to changes in freight traffic patterns.

Problems

The tunnel has long been one of the worst

bottleneck Bottleneck literally refers to the narrowed portion (neck) of a bottle near its opening, which limit the rate of outflow, and may describe any object of a similar shape. The literal neck of a bottle was originally used to play what is now known as ...

s for rail traffic along the Northeast Corridor and its maintenance is costly: * A sharp curve at the south portal of the tunnel prevents southbound trains from exceeding while in the tunnelU.S. Federal Railroad Administration. Washington, DC
"Report To Congress: Baltimore's Railroad Network, Challenges and Alternatives."
November 2005. p. 2.16. * The spacing between tracks is tight * There are water infiltration and drainage issues * A mile-long, 1.34 percent

grade Grade most commonly refers to: * Grade (education), a measurement of a student's performance * Grade, the number of the year a student has reached in a given educational stage * Grade (slope), the steepness of a slope Grade or grading may also ref ...

—the steepest grade on the NEC between Philadelphia and Washington—further constrains train performance. Collectively, the tunnel's height, speed, and capacity limitations threaten the ability for the

Port of Baltimore Helen Delich Bentley Port of Baltimore is a shipping port along the tidal basins of the three branches of the Patapsco River in Baltimore, Maryland on the upper northwest shore of the Chesapeake Bay. It is the nation's largest port facilities fo ...

to be competitive with increased shipping volumes.

Plans for improvements

In June 2008, the

U.S. House of Representatives The United States House of Representatives, often referred to as the House of Representatives, the U.S. House, or simply the House, is the lower chamber of the United States Congress, with the Senate being the upper chamber. Together they ...

voted to support a study of the environmental impacts of different possible replacement tunnels. On January 28, 2010, $60 million in funding was awarded under the

American Recovery and Reinvestment Act American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the "United States" or "America" ** Americans, citizens and nationals of the United States of America ** American ancestry, p ...

to conduct the study, but not the money that would be required for a replacement tunnel. Estimates in 2013 put the cost around $1.5 billion. An outgrowth of the ARRA funds, the B&P Tunnel Project was an environmental and engineering study by the

FRA A friar is a member of one of the mendicant orders founded in the twelfth or thirteenth century; the term distinguishes the mendicants' itinerant apostolic character, exercised broadly under the jurisdiction of a superior general, from the ol ...

, MDOT, and Amtrak to evaluate potential improvements to the tunnel. The study held multiple open houses in 2014–2015 to share information and solicit public input.

Preliminary alternatives

In December 2014, the study published the ''Preliminary Alternatives Screening Report'', in which four alternatives from a total of 16 were selected to be carried forward for further consideration and study: * Alternative 1, No Build: do nothing * Alternative 2, Rebuild/Rehabilitate: improve the existing tunnel to either eliminate the need for a new tunnel or complement a new tunnel * Alternative 3, Great Circle Passenger Tunnel: construct a new tunnel on a wide, continuous arc to the north of the existing tunnel, bypassing it entirely * Alternative 11, Robert Street South: construct a new tunnel roughly parallel to and within 2–4 blocks of the existing tunnel Among the criteria used to evaluate the alternatives was the ability to accommodate double-stack container cars. The 12 eliminated alternatives included several that varied greatly from the existing alignment and bypassed Pennsylvania Station entirely (including one using the former I-170 right of way), as well as several that reused one or more of the three existing tunnel sections.

Selected alternative

In November 2016, Alternative 3B (Great Circle) was specified as the preferred alternative in the ''Final Environmental Impact Statement'' (FEIS) over Alternative 1 (No Build) and two other variations of the Great Circle Alternative (Alternatives 3A and 3C). Highlights of Alternative 3B are: * Total cost (including engineering, design, and construction) of $4.52 billion * Total project length of , including a tunnel * Three ventilation facilities * Approximately 2:30 in travel time savings for Amtrak trains and 1:50 for MARC trains, compared to the existing tunnel * Reconstruction of the West Baltimore MARC Station with high-level platforms * Displacement of 22 residences and six businesses The Federal Railroad Administration released its Record of Decision on the new tunnel, the final step in the

NEPA The National Environmental Policy Act (NEPA) is a United States environmental law that promotes the enhancement of the environment and established the President's Council on Environmental Quality (CEQ). The law was enacted on January 1, 1970.Un ...

process, in March 2017.

2021 plan

In June 2021, Amtrak and the state reached an agreement on a $4 billion plan to replace the tunnel with two single-track tunnels (with an option for two additional tunnels later) by 2032. The tunnels will be named for

Frederick Douglass Frederick Douglass (born Frederick Augustus Washington Bailey, February 1817 or 1818 – February 20, 1895) was an American social reformer, abolitionist, orator, writer, and statesman. After escaping from slavery in Maryland, he became ...

and will allow speeds of versus in the existing tunnel. Penn Line service will be converted to all-electric power as part of the project. Amtrak began the contractor procurement process in June 2022.

References

External links

* U.S. Federal Railroad Administration. ''Report To Congress: Baltimore's Railroad Network, Challenges and Alternatives.'' November 2005. *
Executive Summary
*
"Part 1: Challenges."
Discussing the history and recent state of Baltimore rail infrastructure. *
"Part 2: Alternatives."
Discussing possible replacement tunnel alignments along Presstman Street (see page 7-7) or US Route 40, among others (see page 7–9).
B&P Tunnel Project
{{DEFAULTSORT:Baltimore And Potomac Tunnel Amtrak tunnels Pennsylvania Railroad tunnels Railroad tunnels in Maryland Transportation buildings and structures in Baltimore Tunnels completed in 1873 1873 establishments in Maryland