America's Economy Still Relies on This Crumbling Tunnel

Video narrated and hosted by Fred Mills. This video and article contains paid promotion for Procore.

THE NORTHEAST CORRIDOR is the busiest passenger railway in the whole of the US.

Stretching for more than 450 miles and connecting some of America’s biggest cities, including the capital and New York, it carries over 800,000 people, and 2,000 trains, every day. The region it serves generates 20% of the nation’s GDP and provides 30% of its jobs.

In fact, if the so-called Northeast Megalopolis was its own country it would have the third largest economy in the world — bigger than Germany. And it’s this line that made much of that happen.

Its origins go back to the days of the first railroads in the mid-1800s. But it wasn’t until the late 1960s that it was combined into a single railway.

Then, 1971 saw the launch of Amtrak, America’s national passenger railroad company. It became the primary owner of the line, and now manages most of its infrastructure.

A close call

Fast forward to 2025 and Acela — Amtrak’s flagship service — is capable of going almost as fast as a full-blow high-speed train.

According to the International Union of Railways, trains are officially considered high-speed when they go past 155 mph, and this one falls short by just 5 mph.

Even though Amtrak is introducing new and improved trains in the near future, there are other reasons why the Corridor doesn’t really compare to what people see across Asia and Europe.

Above: Amtrak's Acela trains fall just short of what's defined as true high-speed rail.

You see, that top speed is only possible on certain parts of the line — around 50 of the railway’s 457 miles.

It’s because, right along the route, there are multiple places where trains are either forced into single tunnels and tracks or made to slow down.

And that’s all thanks to infrastructure that was built well over a century ago, which the railway still relies on today. But only for a little while longer.

In late 2023, the Northeast Corridor Commission set out a plan for a series of projects that will bring the most out-of-date sections of the line up to modern standards – all for a whopping estimated cost of $176BN.

Authorised by Congress, the Commission consists of 18 members, including from Amtrak, the US Department of Transportation and the eight NEC states, plus DC.

From huge tunnels under Manhattan to massive bridges across major rivers, it’s a significant amount of work, and much of it is beginning to take shape.

Moving forward

Why now? Because the Bipartisan Infrastructure Law of 2021 saw $16BN allocated to the NEC for repairing and replacing the most out-of-date infrastructure.

This, along with contributions from Amtrak and the various states, gave the projects full funding, meaning construction could begin.

However, it’s only the first step. Completing the whole plan will require more rounds of federal funding in the future. The question is whether the US can complete these projects in time.

Above: There are several major bottlenecks along the Northeast Corridor.

The first choke point between Washington and Boston is just outside Baltimore’s Penn Station, where four tracks are reduced to two.

It’s a tunnel, but the one this train is going into is more than 150 years old, and it’s in a very poor state.

The Baltimore and Potomac Tunnel first opened back in 1873 when those early railroads were being built.

The brickwork in this tunnel — that’s lined this tunnel for more than 150 years — is deteriorating and Amtrak is constantly working to divert water that has infiltrated the tunnel, or pump it out.

At the time of The B1M’s visit it was cold, the water had frozen to the inside. And what’s worse, the floor of the tunnel is sinking too.

On life support

“It does require a high level of maintenance and support as well as attention to make sure all the issues and all challenges of the tunnel being the age it is are being addressed, said Dante DeAnnuntis, Amtrak’s director of integration and operations, Capital Delivery.

“So, it's showing its age, but through a lot of hard work and dedication from Amtrak, we do keep this tunnel in a state of operation for our passengers, and keep everyone safe.”

According to DeAnnuntis it’s the largest bottleneck on the Northeast Corridor, which would be severed if something were to happen to it.

And that would be disastrous. As well as Amtrak, this piece of infrastructure is also used by state commuter and freight trains.

Above: Water infiltration is one of numerous challenges the maintenance team has to face.

Even with the tunnel operating as it should, the timetable here can get very crowded, and more than 10% of trains face some sort of delay.

Then there’s the painfully slow speed restrictions. Trains going through the tunnel have to slow down to 30 miles an hour because of the track curvature.

A much-needed upgrade

Thankfully an immense, $6BN construction project is now underway to phase out this old tunnel and modernise around ten miles of the surrounding corridor.

It’s called the Frederick Douglass Tunnel Program after the civil rights leader and abolitionist, and it’s a two-mile route that will increase the speed up to 100mph.

The upgraded tunnel will take a slightly longer but smoother route further to the north than the existing line.

And that means a lot of tunnelling under built-up areas, which has triggered opposition from some residents in nearby Reservoir Hill. They fear the works could be too noisy, create waste and even cause rodent problems.

There have also been claims the city’s black and low-income communities are being disproportionately affected, leading to a civil rights complaint in 2024.

Amtrak says it has been liaising with local people throughout the process, and is adamant that any impact will be minimal.

Above: A rendering of the new Frederick Douglass Tunnel. Image courtesy of Amtrak.

“What we have been doing in the last several years is involving engaging communities to really explain what the plan is, how we are planning to build this tunnel,” explained Luigi Rosa, assistant VP for the Frederick Douglass Tunnel Program at Amtrak.

“Especially where the tunnel is — it’s an urbanised area, but is so deep that there is no disruption for the community or for the people living on the surface. They will not hear or see anything.”

There will also be ventilation facilities, updated roads and bridges and a new station in West Baltimore for regional trains. Tunnelling is due to start in 2026 with the overall scheme completing in 2035.

Rising high

But there’s a lot more to this railway than tunnels – in fact they make up just 2% of it. When you’re travelling along a line that runs parallel to the coast and crosses multiple rivers, you might expect to find a fair few bridges and, well, that would be an understatement.

The Northeast Corridor has over a thousand of them, and many have come to such a ripe old age that their replacement is now way overdue. A couple in particular operate in such an antiquated way that it seems almost baffling to us today.

The Susquehanna River Rail Bridge is another key part of the line that's already had over 100 birthdays. Amazingly, the structure has been carrying passenger and freight trains over the body of water it’s named after since 1906.

Above: The Susquehanna River Rail Bridge is more than a century old. Image courtesy of Mark McDuff + Duff Drones.

It was built with a Howe truss design — that’s a structural system defined by its vertical and diagonal components that distribute the load.

But perhaps the best thing about it is the rather outdated trick it still performs around 12 times a year. This bridge can move — the middle section can rotate to let big ships pass through.

And while that might sound like a really clever feature, particularly on a bridge of this vintage, it's actually pretty inconvenient because getting that middle section to turn is not a straightforward process.

As it was constructed without any modern technology, a team of around 30 workers have to come out and move it by hand, and that takes a lot of time.

Then there’s the fact that, when trains are able to go over it, they can only do so at 90 mph max. Not as bad as in Baltimore, but quite a way short of 155.

Out with the old...

That's why in a few years time Amtrak is going to be saying goodbye to a piece of infrastructure that’s served it well for generations, but that's no longer really fit for purpose.

In its place is going to be something not just bigger, but better and more than able to deliver those higher speeds.

Instead of just two tracks on a single bridge, the crossing is being upgraded to four tracks over two bridges, and the first one is almost ready to start work.

Now, we don't know for certain what this new bridge is going to look like yet because it's still in the design phase. But some initial conceptual renders have been released that kind of show the direction of travel.

And they indicate that we're going to be getting a bridge that looks pretty different to the one that's there now.

Above: The new bridge(s) is going to have a much larger clearance for boats than the one it's replacing. Image courtesy of Amtrak.

Gone is the rusty steel trusswork on top of brick piers that rise only a short distance out of the river. Costing $2.7BN, the new crossings are going to have concrete decks and piers, with a greater gap between the water and the bridge.

In the centre, a 120-metre-long tied arch channel span will bear some resemblance to the earlier structure. This is where, thanks to an 18-metre vertical and 70-metre horizontal clearance, ships will be able to travel underneath the bridges without them having to move.

Contracts were awarded in December 2023, and preparations are now in full swing. A joint venture between contractors Flatiron and Herzog was given the role of Construction Manager At Risk, and is delivering the project in two phases.

Doing the groundwork

“There's been a great collaboration on the project to redesign parts of the project to get the construction as far away from the existing rail as possible,” revealed Adam Mathews, senior operations manager for Flatiron/Herzog.

It's a rail bridge that's very heavy. Ten-foot-diameter shafts in the water, very stout piers. We have 12-foot-deep steel girders, all of which is going to go right across for almost a mile. So it's a big operation to build a bridge in this way.

Although completion isn’t expected for more than a decade, preliminary works have already begun. One example is the removal of small piers that used to be here supporting an historic bridge to clear the path and make way for that new bridge structure.

Above: The last of the old bridge piers were taken out in late 2024. Image courtesy of Amtrak.

Now, at this point you might be thinking ‘well, that all sounds great, but when are we actually going to get spades in the ground along this corridor, especially when things seem pretty urgent?’

Well, the good news is work is already happening. And the next bridge I’m heading to see is more than three quarters complete. For that I’ll need to head further up the line, towards one of my favourite cities: New York.

But first I’m going to make a quick stop to visit a building that’s just as important to keeping this railway functioning as all the stuff that makes up the infrastructure.

Stopping off in Philly

Around halfway along the Corridor between Baltimore and New York is Philadelphia. It’s the sixth most populated city in the US and home to one of the country’s most beautiful stations, a place that’s also getting a big overhaul — both inside and out.

If you come down to the area around Philadelphia's 30th Street station and there's loads happening, lots of anticipation, big construction work going on. And this area could be seeing a much wider regeneration in the years to come.

That’s because it’s part of a major idea to redevelop this part of the city with new roads, bridges and even a tunnel linking the main station to the subway.

The external plaza is being expanded with more public space that will better connect it with the surrounding neighbourhood.

Above: The future of 30th Street Station. Image courtesy of Plenary Infrastructure Philadelphia + Amtrak.

But at the centre of all that — anchoring it all — is 30th Street station itself. It’s one of the busiest passenger stations in the whole of the US, and included in the National Register of Historic Places.

The station is getting a half-billion-dollar renovation that’ll bring it up to date. Facilities are being modernised, new retail units are being added and Amtrak’s offices are getting a revamp, all while preserving some of the station’s most historic elements like the bronze doors, wooden benches and the incredible 1930s lights.

Although it’s not yet certain when or even if the redevelopment of the wider area here will happen in its entirety, the improvements to 30th Street look set to finish in 2027.

(Another) bridge to the past

The next stop up the line is New Jersey’s Portal Bridge. Again, it’s another key piece of infrastructure that’s over a century old and does a really important job. It carries trains from Newark across and over into Penn Station in the middle of Manhattan.

As well as Amtrak, the Portal Bridge is used by New Jersey Transit, America’s third largest transit operator. With over 150,000 passengers crossing it every day, it’s thought to be the busiest train span in the Western Hemisphere, and yet, delays are frequent.

Due to their age, the mechanics that also make this bridge move are prone to malfunctioning. It’s old, it’s tired and needs replacing — just like the Susquehanna Bridge, but in this case they’re well on with its replacement.

The new Portal North Bridge is being built right now, and when it opens it's going to take over the job of the original Portal Bridge, giving it a break after a century of carrying trains. That old bridge is then going to be demolished.

Above: The old Portal Bridge (bottom left) alongside the new Portal North Bridge. Image courtesy of The Railway Drone.

“We're building a new bridge next to an existing railroad bridge. When you do that, when you're building caissons and piles, you're going to have some vibration that will bring settlements,” explained Ashok Nayee, Amtrak’s director of capital construction for the Portal North Bridge.

“The project team worked together to make sure we had a comprehensive plan and we followed the plan to ensure that we addressed settlement issues in a timely fashion.”

The bridge’s three arches are so big they had to be constructed in upstate New York, near Albany, floated down the Hackensack River, and lifted into place.

“[There have been] zero delays with this bridge going from 20 feet on the old bridge to 50 feet, and it’s a fixed span. There's no need to open it and the maritime traffic gets to go through 24/7,” added Scott Masskant, construction program manager for the Portal Bridge at NJ Transit.

Making progress

Now, granted that might not sound like a huge deal to people from other parts of the world, but in a country that struggles to build new infrastructure like this, it’s a massive step forward.

When it’s finished in 2027, this bridge will form the first big piece of the giant Gateway Program puzzle – a comprehensive set of works that’s being described as the most urgent infrastructure scheme in the United States.

It includes the expansion of New York’s Penn Station, along with a massive underground route that will connect this new bridge with America’s biggest metropolis.

Above: The New York skyline is clearly visible from the Portal North Bridge. Image courtesy of The Railway Drone.

Coming into New York from New Jersey, under the Hudson River, takes you through another point where this route really narrows down — this time into two single-track rail tunnels. Those tunnels are also showing their age.

Constructed back in the early 1900s, the North River Tunnels were built before the age of TBMs, that’s: tunnel boring machines.

Although the systems that were used did bear some resemblance to 21st-century TBMs in appearance, the way they actually worked, as you’d imagine, was a lot more primitive.

Instead of giant cutting heads powered by electricity, these ‘tunnel shields’ used compressed air to blast their way through the soft, muddy ground beneath the Hudson.

When nature calls

Fast forward to today and as well as the usual wear and tear that you'd expect with a century-old piece of infrastructure, the arrival of Hurricane Sandy in 2012 made things a lot worse.

The tunnels were flooded with seawater, which put trains out of action for five days. It also left behind corrosive chemicals that have continued to degrade the concrete lining and some of the systems inside.

Another cause for concern is that this represents another single point of failure for the Northeast corridor, which means if something was to go seriously wrong, it could lead to a 75% reduction in services or even a complete shutdown, which would be catastrophic.

If they were to fail it would cost the US more than $100M per day. That is why a new tunnel, the Hudson Tunnel, is now being constructed, just down river.

Having a second crossing will double the capacity and make these services faster and more reliable, while ensuring the country’s most heavily-used passenger line can continue for another century or so and even beyond.

Above: A map showing the current and new crossings under the Hudson River.

Once the new tunnel is complete, the existing one will be given a full rehabilitation and then eventually both will be able to operate together.

Ground breaking began back in November 2023 and there’s plenty of activity to see today. Especially if you come down to Hudson Yards, New York’s newest high-rise district.

Teams here are putting in a new section of concrete casing and working to create a right of way for that new tunnel from the river, over, under Hudson Yards and into Penn Station.

That’ll be done using the cut and cover method, with horizontal bracing that also acts as supports where The High Line passes over the top.

The first sections, between 10th and 11th Avenue, were completed back between 2013 and 2018.

Another sign the project is finally moving forward is the activity happening out on the water.

Ensuring stability

Barges are currently carrying out ground stabilisation, which has to happen before the tunnel boring machines can begin their journeys.

So far, they have built a test cofferdam, which is where a barrier is placed inside the river, leaving a space in the middle for construction work.

To do this, a series of piles were driven into the ground, with sheets placed in between, creating a sealed dry area once the water has been pumped out.

They have also been used for geophysical surveying and sampling before the main work begins.

This will include injecting grout into the silt of the riverbed, and mixing cement into the existing soil, to make the ground a lot more solid.

Above: The ground has to be stabilised before any tunnel boring can be carried out. Image courtesy of GDC + Amtrak.

Meanwhile, back in New Jersey, preparations are already underway near what will become the western tunnel portal.

A road bridge is being constructed to make way for the new train tracks, and the job has been progressing smoothly.

The big picture

So, you get the idea. There's loads of stuff either planned or happening here, but what does it all going to mean?

Well, when these works finish, and the new faster trains are rolled out, the speed limit on this railway is going to be increased to 160mph, technically taking it into that high-speed category.

Now, it might not sound like a big increase, but actually it is pretty significant because it means the trains are going to be able to travel faster for longer cutting journey times and effectively bringing major cities closer together.

Even so, 160 mph is still no match for the bullet trains that other nations have been enjoying for decades.

Frankly, America’s best hope for coming close to that lies in megaprojects over on the opposite side of the country — particularly Brightline West.

It’s a new 200mph railway that’s set to connect Las Vegas to Los Angeles in just three hours by 2028.

Above: Many predict Brightline West will be the first true high-speed railway in the US. Image courtesy of Brightline. 

For now though, the Northeast Corridor remains the best of what the US can offer in terms of rail.

It’s still a long way behind what much smaller economies are delivering in other parts of the world – something that’s difficult to fully comprehend.

The sad truth is that when it comes to US infrastructure, seeing at least some degree of consensus and steady progress has to be taken as a win.

The scale of the challenge

Taking a journey along the Northeast Corridor really opens your eyes to the state of America's infrastructure, which has been widely reported for years.

It's not until you go into those tunnels and you stand under those bridges that it really hits you and it really comes home.

Millions of people and a huge chunk of this country's economy relies on pieces of infrastructure that have just been neglected for such a long time.

The construction teams, the leaders, the men and women who are making this happen have been dealt an incredibly tough hand — infrastructure that was very old even when they inherited it and they’re now trying to do the best they can with a tough situation.

America owes so much of its success to infrastructure. Looking back through history, the Transcontinental Railroad, the bridges, the tunnels, the airports, things like the Hoover Dam are what made it.

But it's almost forgotten that; it’s almost like the American dream is no longer extended to infrastructure.

That's changing now, as things have got to such a state that there is now wide support for getting it sorted. Let’s hope it's not too little, too late.

See how Procore enables intelligent project management through one platform here.

This video and article contain paid promotion for Procore. Video narrated and hosted by Fred Mills. Additional footage and images courtesy of Amtrak, Mark McDuff + Duff Drones, NJ Transit, The Railway Drone, CBS, GDC, CTSL Railfan, Mega Trains Rail Productions, Plenary Infrastructure Philadelphia, Brightline, David Wilson / CC BY 2.0, 8 News Now Las Vegas, FOX 5 Las Vegas, Governor Andrew M. Cuomo, NBC LA, New York Daily News, PBS Newshour and WJZ.

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