The United States is spending $6 billion to replace a 150-year-old railway tunnel that is still in operation — the project spans 16 km in Baltimore and includes building the new tunnel next to the old one without stopping a single train.

Written by Douglas Avila

Published on 20/04/2026 at 06:50

Updated on 02/05/2026 at 14:55

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The United States spends US$6 billion to replace a 150-year-old railway tunnel that still works — the project spans 16 km in Baltimore and includes a new tunnel built next to the old one without stopping a single train

Beneath the streets of Baltimore, in the American state of Maryland, there is a railway tunnel that was built during the American Civil War. It is 150 years old, 2.2 km long, and is still used by 14 million passengers annually today.

It is the Baltimore & Potomac tunnel, known as B&P. And it is the biggest railway bottleneck in the United States.

Now, Amtrak — the US passenger train operator — is building a new tunnel next to it. The project is called the Frederick Douglass Tunnel and costs US$6 billion.

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Why a 150-year-old tunnel is the biggest railway bottleneck in the US

The B&P tunnel connects Baltimore’s Penn Station to the capital Washington D.C. and the state of Virginia.

It is part of the Northeast Corridor, the busiest railway corridor in the United States, linking Boston to Washington via New York and Philadelphia.

Millions of Amtrak and MARC system passengers depend on this single tunnel. If it closes for maintenance, the entire East Coast of the US feels the impact.

Amtrak itself describes the B&P as “a single point of failure for the 14 million customers who rely on it.”

Trains passing through the old tunnel are forced to reduce speed drastically. While modern sections of the corridor allow speeds exceeding 200 km/h, inside the B&P trains crawl at a fraction of that.

The 150-year-old structure requires constant maintenance, causing frequent delays.

To give you an idea, the tunnel opened in 1873 — just eight years after the end of the American Civil War. At that time, steam trains were a technological novelty.

Today, modern electric trains are forced to use the same underground passage that was designed for coal locomotives.

150-year-old B&P Tunnel with worn bricks

What is the Frederick Douglass Tunnel and why does it cost US$6 billion

The new tunnel will be approximately 3.2 km long — two parallel tubes designed for electric passenger trains.

But the project goes far beyond a tunnel.

In total, the work extends for 16 km of the Northeast Corridor around Baltimore. It includes:

Two parallel high-capacity tubes for the new tunnel
Replacement of bridges along the corridor
A new, fully accessible MARC station in West Baltimore
Modernization of fire safety and emergency evacuation systems
Improvements to roads and bridges in the region

When completed, trains will be able to travel up to 160 km/h inside the new tunnel — more than three times faster than in the current tunnel.

The name honors Frederick Douglass, an abolitionist and former slave who lived in Baltimore in the 19th century.

The challenge of building a tunnel without stopping trains

The most impressive aspect of the work is that it must happen while the old tunnel continues to function.

Closing the B&P would mean interrupting the most important railway corridor in the United States.

Therefore, the new tunnel is being built next to the old one, in parallel, without interrupting a single journey.

In January 2026, Amtrak completed critical geotechnical investigations in Baltimore to map the soil and ensure that excavations would not compromise existing structures.

The main contract was awarded to the Kiewit/J.F. Shea consortium in February 2024. The construction of the tunnel itself is being carried out by the UIT Infrastructure/JFSHA consortium.

Three emergency evacuation facilities are planned — something the 150-year-old tunnel simply does not have.

The estimated completion is 2035.

Amtrak train at Baltimore's Penn Station

Where the US$6 billion comes from

The project’s funding comes from several combined sources.

Most of it comes from the Infrastructure Investment and Jobs Act, the bipartisan infrastructure law signed in 2021 that allocated hundreds of billions of dollars for projects across the US.

In addition to the federal government, the Federal Railroad Administration, Amtrak’s own revenues, and the state of Maryland contribute resources.

The project also includes a US$50 million community investment program, aimed at direct improvements in the West Baltimore region.

Amtrak estimates that the project will create tens of thousands of jobs during the construction period.

To understand the scale: 16 km of work in the heart of a city

Comparing with Brazilian projects helps to dimension the work.

The total length of the project — 16 km of railway corridor — is equivalent to the distance between Estação da Luz and Congonhas Airport in São Paulo.

But in Baltimore’s case, this entire stretch needs to be modernized beneath an already built city, with streets, buildings, and utility systems above.

It’s like renovating the foundation of a house while the family continues to live in it.

Several government agencies are involved: the U.S. Department of Transportation, the Federal Railroad Administration, the Maryland Department of Transportation, and the city of Baltimore.

Aerial view of Baltimore with railway corridor

What changes when the new tunnel is ready

When the Frederick Douglass Tunnel becomes operational, passengers will immediately feel the difference.

Shorter travel times between Washington and Baltimore. Greater schedule reliability. Fewer cancellations due to maintenance.

For the American railway system as a whole, it means unlocking the biggest bottleneck of the Northeast Corridor — the corridor that moves more passengers than any other in the United States.

A tunnel built in the Civil War era is being replaced by a structure designed to last another century.

However, the project faces challenges. The completion deadline of 2035 is an estimate, and large infrastructure projects in the US historically suffer delays and budget overruns. The old tunnel itself, when it was built in 1873, also had a deadline — which was exceeded by years.

The question that remains is whether the US will be able to deliver on time a project that, in scale and complexity, is comparable to what China builds in half the time.

The United States is spending $6 billion to replace a 150-year-old railway tunnel that is still in operation — the project spans 16 km in Baltimore and includes building the new tunnel next to the old one without stopping a single train.

The United States spends US$6 billion to replace a 150-year-old railway tunnel that still works — the project spans 16 km in Baltimore and includes a new tunnel built next to the old one without stopping a single train

Why a 150-year-old tunnel is the biggest railway bottleneck in the US

What is the Frederick Douglass Tunnel and why does it cost US$6 billion

The challenge of building a tunnel without stopping trains

Where the US$6 billion comes from

To understand the scale: 16 km of work in the heart of a city

What changes when the new tunnel is ready

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The United States is spending $6 billion to replace a 150-year-old railway tunnel that is still in operation — the project spans 16 km in Baltimore and includes building the new tunnel next to the old one without stopping a single train.

The United States spends US$6 billion to replace a 150-year-old railway tunnel that still works — the project spans 16 km in Baltimore and includes a new tunnel built next to the old one without stopping a single train

Why a 150-year-old tunnel is the biggest railway bottleneck in the US

What is the Frederick Douglass Tunnel and why does it cost US$6 billion

The challenge of building a tunnel without stopping trains

Where the US$6 billion comes from

To understand the scale: 16 km of work in the heart of a city

What changes when the new tunnel is ready

While an average building in London or New York takes three years to be completed, in China a 26-story tower went up in five days with about 100 workers, and the global modular construction market already moves US$ 95 billion per year.

Australia installs giant concrete structures on the seabed 800 meters from the shore to create an ocean intake for desalination that will draw in saltwater and produce 30 million liters of drinking water per day.

A public school student single-handedly created a machine capable of treating water for up to 50 people using only solar energy. It was awarded third place at one of the most important science fairs in the world.

Goodbye traditional washing machine: Panasonic surprises housewives with the NA-G5 featuring four drums, a 13 kg washer and dryer, a 12 kg dryer, independent mini washers, a heat pump, and a 4-in-1 system awarded at the German Design Award.

While cities spend fortunes patching potholes and tons of plastic become waste, the Netherlands transforms over 218,000 recycled cups into a modular bike path that can conceal drainage, cables, and pipes.

While communities suffer from water scarcity and the advancing desert, women in Morocco use nets high up in the mountains to trap fog droplets, fill reservoirs, and transport drinking water through more than 10 km of piping.

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