Replacing Old Railway Bridges in the UK: Three Projects, Three Methods, Three Work Windows

 

source : Dchain, 2026

Three recent projects in England show three different ways to replace an ageing railway bridge on a line that has to reopen. Two are scheduled for the Christmas break; the third was completed at the end of October.

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For the Croydon bridge project, Network Rail says the work was deliberately scheduled over Christmas and New Year because road traffic and rail passenger numbers are typically lower than at other times of the year. Choosing the right possession window is one of the core decisions in any job on an operational railway.

As of 12 November 2026, three bridge replacements are worth comparing: one in Croydon (south London), one at Church Fenton (between Leeds and York), and one in Wakefield. All three replace old bridges, but with different methods and different work windows.

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Project 1: Selhurst Road, Croydon Moving a Bridge with SPMTs

Source : Inside Croydon, November 3, 2026

Context. The Victorian-era railway bridge over Selhurst Road was built in 1861, making it around 165 years old. Network Rail says the bridge has been repaired several times and has now reached the end of its serviceable life, so it must be replaced.

Method. The new bridge will be assembled on site, then moved into position using Self-Propelled Modular Transporters (SPMTs), remote-controlled modular vehicles used to carry very heavy loads. The bridge move is scheduled for 27 December to 2 January.

Why not a crane? During planning, engineers identified underground utility pipes beneath the road, which means a conventional heavy-lift crane cannot be used safely. Network Rail acknowledges the SPMT method needs a longer road closure, but says it is the safest and most practical solution.

Impact. Selhurst Road beneath the bridge will be fully closed to vehicles and pedestrians from 8am on Saturday 12 December 2026 until 5pm on Sunday 10 January 2027. Pedestrian access on either side of the bridge remains, but there is no access underneath it.

Cost. Local outlet Inside Croydon reports the scheme is estimated at around £60 million. This figure comes from a media report, not from an official announcement I could find.

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Project 2: Common Lane, Church Fenton Early Replacement

source : RailwaySupply, October 10, 2026

Context. The Common Lane railway bridge at Church Fenton was first built in 1901. Its replacement is linked to the Transpennine Route Upgrade (TRU) between Leeds and York.

Method. Between Saturday 24 October and Sunday 1 November 2026, during a nine-day closure, construction teams replaced the bridge and also installed new overhead line infrastructure for future electrification.

The strategic angle. TRU said the bridge was nearing the end of its serviceable life, and replacing it now, about a year earlier than strictly necessary, let the programme use an access window that was already planned on the operational railway. Network Rail said this approach reduces further disruption to the community when the overhead line equipment is later energised.

What happens next. Work has now started on relocating diverted utility services within the new structure, before the road is restored and reopened in June 2027.

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Project 3: Agbrigg Road, Wakefield — Demolition and a Two-Section Deck

source : Geomechanics.io, November 06, 2026

Context. The Agbrigg Road bridge, beside Sandal & Agbrigg station, carries trains between Doncaster and Leeds. It has been reported as "structurally substandard."

Method.

1. Engineers first remove the track and ballast above the bridge.
2. A 50-tonne excavator takes down the existing structure.
3. The new deck, built in two sections at a nearby compound, is installed.
4. The railway is reinstated.

The work is scheduled for the Christmas shutdown at a cost of almost £5 million.

Road impact. Road disruption starts earlier: temporary traffic lights from 8 November, followed by Saturday-night closures from 14 November.

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Side-by-Side Comparison

Aspect	Croydon (Selhurst Road)	Church Fenton (Common Lane)	Wakefield (Agbrigg Road)
Year built	1861	1901	Not stated
Main method	Assemble on site, move with SPMTs	Replace during a 9-day closure	Excavator demolition, two-section deck
Reason for method	Underground utilities rule out a crane	Use a planned access window	Prefabrication at a nearby compound
Timing	27 Dec–2 Jan (bridge move)	24 Oct–1 Nov 2026	Christmas shutdown
Road closure	12 Dec 2026–10 Jan 2027	Reopens June 2027	Staged from 8 Nov
Cost (reported)	~£60m (local media)	Not stated	Almost £5m

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5 Takeaways for Engineers

These points are my analysis of the pattern across the three projects, not published specifications.

1. Build off the critical path, install in a short window. Croydon and Wakefield both prepare the new structure away from its final position, then install it in limited time. The more work moved off the critical path, the shorter the time the line has to stay closed.

2. Buried utilities can decide the method. At Croydon, pipes beneath the road changed the lifting strategy. A thorough early utility survey is not a formality; it can determine how the structure is built.

3. The safest method is not always the fastest. Network Rail itself says SPMTs need a longer road closure, yet chose them because they are safest. Safety and duration of disruption have to be weighed openly.

4. Combine work within one access window. At Church Fenton, the bridge replacement was brought forward a year and combined with overhead line installation. One closure replaced two separate disruptions.

5. Communicate impacts to the public in stages. Wakefield starts with temporary traffic lights, then Saturday-night closures. Stepped notice helps local people adjust.

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Relevance Beyond the UK

Many railway networks around the world, including in Indonesia, have older bridges that keep ageing. The concepts of work windows, off-line prefabrication, and moving a complete structure can be useful to study. Regulatory context, timetable pressure, equipment availability such as SPMTs, and costs differ widely by country, so any method needs to be reassessed for local conditions.

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Key Data at a Glance

Parameter	Detail
Croydon bridge	Selhurst Road, built 1861 (~165 years)
Croydon method	Assemble on site, move with SPMTs
Croydon bridge move	27 Dec 2026–2 Jan 2027
Selhurst Road closure	12 Dec 2026 (8am)–10 Jan 2027 (5pm)
Croydon estimated cost	~£60 million (local media report)
Church Fenton bridge	Common Lane, built 1901
Church Fenton closure	24 Oct–1 Nov 2026 (nine days)
Church Fenton road reopening	June 2027
Wakefield bridge	Agbrigg Road, Doncaster–Leeds line
Wakefield method	50-tonne excavator, two-section deck
Wakefield cost	Almost £5 million

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Data Sources

Source	Detail
New Civil Engineer, 12 Nov 2026 (newcivilengineer.com/latest/engineers-to-use-spmts-to-replace-160-year-old-croydon-railway-bridge-over-christmas-12-11-2026/)	Croydon: SPMTs, buried utilities, schedule
Network Rail, "Replacing Selhurst Road Bridge" page (networkrail.co.uk)	Why Christmas and New Year was chosen
Inside Croydon, 3 Nov 2026 (insidecroydon.com/2026/11/03/month-long-closure-of-selhurst-road-for-bridge-replacement/)	Bridge age, estimated £60m cost
Secret London	Network Rail statement, road closure dates
New Civil Engineer, 2 Nov 2026 (newcivilengineer.com/latest/engineers-replace-125-year-old-bridge-and-prepare-line-for-tru-electrification-between-leeds-and-york-02-11-2026/)	Church Fenton: nine-day closure, TRU
New Civil Engineer, 5 Nov 2026 (newcivilengineer.com/latest/engineers-to-replace-structurally-substandard-wakefield-rail-bridge-over-christmas-period-05-11-2026/)	Wakefield: method, cost, road disruption

This article is for information only. Schedules and project conditions follow reports as of 12 November 2026 and may change.

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Which method do you think suits an old bridge on a busy line best? Share your thoughts in the comments below 👇

Gansu–Zhejiang UHVDC: A 2,370 km Transmission Line Cutting Through Mountains to Carry Clean Energy

source : cgtn, 2026

One of its hardest sections, 486 km through the mountains of Shaanxi, has just been completed. Behind the cables and towers is civil engineering work on a continental scale.

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In mid-October 2026, State Grid Shaanxi Electric Power, a subsidiary of State Grid Corporation of China (SGCC), reported that the Shaanxi section of the ±800 kV Gansu–Zhejiang UHVDC transmission project had been built and connected.

It sounds like power-sector news, but for civil engineers it is a story worth reading. A line thousands of kilometres long has to cross ridges, valleys, and extreme elevation changes. Every tower needs a foundation, access, and construction logistics. This article covers what the project is, why it matters, and the civil engineering challenges behind it.

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What Is UHVDC?

UHVDC stands for ultra-high voltage direct current: very high voltage power transmission using direct current. By the industry definition, ultra-high voltage means more than 800 kV DC or more than 1,000 kV AC.

Compared with conventional transmission lines, ultra-high voltage lines increase capacity, extend transmission distance, and reduce transmission losses. That is why the technology is used to move electricity from energy-producing regions in northwest China to consumption centres on the eastern coast.

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Gansu–Zhejiang Project Data

These are the figures recorded in project sources:

• Voltage: ±800 kV, flexible DC
• Rated capacity: 8 GW (8 million kW)
• Line length: about 2,370 km
• Investment: about CNY 35.3 billion (roughly US$4.82 billion)
• Provinces crossed: Gansu, Ningxia, Shaanxi, Henan, Anhui, and Zhejiang
• Converter stations: Wuwei (Gansu) and Shaoxing (Zhejiang)
• Annual supply: more than 36 billion kWh to Zhejiang, with more than half from renewable sources
• Construction start: July 2024
• Work packages: 22 sections

The project is billed as the world's first ultra-high voltage flexible DC line. That "world first" claim comes from SGCC and the coverage of it, so it is best read as the operator's claim.

Hitachi Energy is supplying HVDC technology for the project. An industry source gives 2026 as the target for operation.

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The Shaanxi Section: Difficult Terrain

The Shaanxi section runs about 486 km through four cities and 11 counties, including Baoji, Hanzhong, Ankang, and Shangluo.

The numbers describe the terrain clearly:

• The route crosses elevations from 600 to 2,100 metres
• High mountains make up 55.3% of the route

That means more than half of the line sits in mountainous terrain. For civil engineers, this has real construction consequences.

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What This Means for Civil Engineering

The sources I found do not detail tower counts or foundation methods. But a project like this brings civil challenges that are common to transmission lines in mountainous terrain, and they offer a useful way to think about it:

1. Tower foundations in variable ground. Each tower location can differ in geology, from hard rock to slopes at risk of sliding. Foundation design has to adapt.

2. Access and logistics. Hauling materials and equipment to mountain sites often requires temporary roads or specialised transport. On steep terrain, logistics can be as demanding as the construction itself.

3. Slope stability and environment. Clearing land on slopes means managing erosion, drainage, and revegetation after construction.

4. Cross-region coordination. With 22 sections and six provinces, the challenge is also project management: design standardisation, quality control, and schedules that stay in sync between sections.

5. Converter stations as major civil works. At each end of the line sits a converter station, a complex of buildings and heavy foundations for very large electrical equipment.

Points 1 to 5 are general analysis of transmission projects in mountainous terrain, not specific data from the Shaanxi section.

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Why Flexible DC Technology Matters

The project uses flexible DC transmission technology. In general, systems of this kind are known for being easier to control and better suited to integrating variable renewable sources such as solar and wind. That matters here because more than half of the electricity delivered to Zhejiang comes from renewable sources.

The wider context: according to an industry source, the renewable share carried by China's national UHVDC lines had already passed 55% in 2023. Long-distance transmission has become a backbone of the country's clean energy strategy.

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Lessons for Engineers Elsewhere

1. Renewable energy needs civil infrastructure, not just panels and turbines. The best sites for solar and wind are often far from demand centres. The transmission network that connects them is a major civil project.

2. Splitting a project into many sections helps maintain speed. With 22 sections, work can proceed in parallel. The challenge lies in coordination and uniform quality standards.

3. Difficult terrain must be built into planning from the start. With 55.3% of the route in high mountains, geological studies, access, and logistics have to be core design inputs.

4. Archipelagic and mountainous countries face similar challenges. Indonesia has renewable potential in places that are often far from load centres, from geothermal in the mountains to hydro in the interior. Long-distance transmission cases like this one are worth studying, with the caveat that regulatory context, scale, and cost differ greatly.

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Key Data at a Glance

Parameter	Detail
Project name	±800 kV Gansu–Zhejiang UHVDC (flexible)
Owner/operator	State Grid Corporation of China (SGCC)
Rated capacity	8 GW
Line length	~2,370 km
Investment	~CNY 35.3 billion (~US$4.82 billion)
Provinces crossed	Gansu, Ningxia, Shaanxi, Henan, Anhui, Zhejiang
Converter stations	Wuwei (Gansu) and Shaoxing (Zhejiang)
Supply to Zhejiang	>36 billion kWh per year
Renewable share	More than half
Construction start	July 2024
Number of sections	22
Shaanxi section	~486 km, 4 cities, 11 counties
Shaanxi elevation range	600–2,100 m
High-mountain share (Shaanxi)	55.3%
Shaanxi section status	Construction and line connection completed (reported 14 Oct 2026)
Operation target (per industry source)	2026

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Data Sources

Source	Detail
Powerline (14 Oct 2026)	Shaanxi section completion, length and terrain data
China Daily	Construction launch, capacity, investment, route
Enerdata	UHV definition, project details
Hitachi Energy	HVDC equipment supply, operation target, 2023 renewable share

This article is for informational purposes. The civil engineering points in "What This Means for Civil Engineering" are general discussion, not published project specifications. Figures and project status follow sources as of October 2026.

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Which civil challenge do you think is hardest on a transmission project in mountainous terrain? Share your thoughts in the comments below 👇

FEMA P-259 Updated: New Guidance for Breaking the "Flood, Repair, Flood Again" Cycle

 

civilciv, 2026

A home floods, gets repaired, then floods again. In some floodplains, this cycle repeats every few years. FEMA has just released an updated edition of the guidance designed to break it.

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Anyone who works in flood mitigation knows the pattern. A house is inundated, the owner repairs the walls, floors, and furnishings, and a few years later the water returns. Every round costs money, time, and the wellbeing of the people who live there.

FEMA (the Federal Emergency Management Agency) has released an updated edition of FEMA P-259: Engineering Principles and Practices for Retrofitting Flood-Prone Residential Structures, a technical guide to retrofitting residential buildings in flood-prone areas. It is written for engineers, architects, and local code officials.

This article covers what the guide is for, the five retrofit approaches it works with, and what engineers outside the United States can take from it.

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What Is FEMA P-259?

FEMA P-259 provides engineering design guidance, economic guidance, and best practices for retrofitting residential structures in flood-prone areas. The previous edition, the Third Edition, was published in 2012, and the one before it in 2001.

Its core purpose ties directly to an objective of the National Flood Insurance Program (NFIP): breaking the cycle of repetitive flood damage. Many buildings have been flooded, repaired, and flooded again, and in some floodplains that cycle recurs every few years.

What the Updated Edition Covers

According to the announcement published by the Association of State Floodplain Managers (ASFPM), the updated edition includes:

• Detailed sections on evaluation, planning, and retrofit design measures
• Updated case studies of completed retrofit projects
• Content used to refresh FEMA's training course on retrofitting flood-prone residential structures
• Both active and passive approaches, using dry and wet floodproofing techniques

Scope and Limits

The guide focuses on one- to four-family residences exposed to flooding without wave action. It is not a guide for large commercial buildings or for coastal sites where waves are a factor. FEMA publishes separate guidance for coastal construction.

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The Number That Explains Why This Matters

FEMA estimates that buildings meeting or exceeding NFIP minimum floodplain management requirements incur, on average, 65 percent less flood damage than buildings that predate local floodplain regulations.

That figure says two things at once. First, good design standards make a measurable difference. Second, a large stock of older buildings was built before those standards existed and still carries high risk. Those buildings are the main target of retrofitting.

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Five Retrofit Approaches Within the P-259 Framework

The P-259 framework covers five groups of methods for reducing flood damage to existing buildings.

1. Elevation

The building is raised above the design flood level, for example by lifting the structure onto a taller foundation, piers, or columns. It is the classic approach and works well because water passes underneath while living space stays dry. The trade-offs are access, stairs, and the need to protect utilities.

2. Relocation

The building is moved out of the floodplain. This is the most definitive option because it removes exposure to the hazard altogether, but it is also the heaviest in cost, land, and social impact.

3. Dry Floodproofing

Walls and openings are made watertight so that floodwater cannot enter. This suits certain conditions, but it demands that the structure can resist water pressure, that seals are maintained, and often that someone takes action when a flood arrives.

4. Wet Floodproofing

Water is allowed into designated non-living areas, such as a garage or lower enclosure. The building is designed with flood openings so water pressure equalizes, and it uses flood-resistant materials. The approach accepts that water will come in and works to minimize the damage.

5. Levees and Floodwalls

An earthen levee or a wall is built around the building. This is a "grey" solution that protects a single property or a small group of properties, and its maintenance needs and failure risk must be accounted for.

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How This Connects to Our Earlier Articles

P-259 complements two topics we have already covered.

With Green vs Grey Infrastructure: That article looked at choices at the district scale, meaning how to manage stormwater through a mix of green and grey infrastructure. P-259 works at the building scale. In practice they complement each other: good district drainage reduces how often flooding happens, while building retrofits reduce the damage when water comes anyway.

With Resiliency-First Design: Resilience-oriented design is usually discussed for new projects. P-259 shows the other side, applying the same mindset to existing buildings, which vastly outnumber new ones.

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Relevance Beyond the United States

P-259 was written in the context of United States regulation, especially the NFIP. Its legal and insurance references do not transfer directly to other countries. The engineering principles, however, are relevant anywhere flooding is a recurring risk, including much of Southeast Asia.

One interesting example: the stilt houses found across many parts of Indonesia are, in essence, a traditional form of elevation. Water is allowed to pass beneath while living space stays above it. The P-259 framework can help engineers put a more systematic technical and economic basis under approaches like this.

A few things need adapting when borrowing ideas from P-259:

• The design flood level must come from local hydrological data, not from US figures.
• Materials and construction methods need to fit local practice, availability, and soil conditions.
• Local building codes and land-use rules remain the primary legal reference.
• Cost estimates from foreign publications cannot be used as they stand.

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Important Notes When Reading This Guide

One point is worth remembering. For the Third Edition, a building-science reference catalog (BASC/PNNL) noted that its cost estimates are outdated because of the publication date. Anyone using technical guidance of this kind should check the base year of any cost figures and adjust them to current local prices.

Also, this article relies on published announcements and summaries of the updated edition. For real design work, read the official FEMA P-259 document directly, because the technical details are what drive engineering decisions.

FEMA also offers a short overview course, IS-280 (about 1.5 hours), covering the revised P-259. It is aimed at engineers, architects, floodplain managers, and code officials.

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5 Takeaways for Civil Engineers

1. Retrofitting is a far bigger market than new construction. Most of the buildings that will exist in 2050 are already standing today. The ability to assess and improve the resilience of existing buildings is an increasingly valuable skill.

2. Breaking the damage cycle costs less than repairing it repeatedly. The one-time cost of a retrofit should be weighed against decades of accumulated repair costs from repeated flooding.

3. No single method fits every case. Elevation, relocation, and floodproofing each suit different conditions. The best choice depends on flood depth, structural condition, soil, and the owner's means.

4. Buildings and districts must be considered together. Retrofitting a house without improving district drainage solves only part of the problem. The hybrid thinking from the Green vs Grey article applies here too.

5. Foreign guidance is a starting point, not a template. Take the principles, test them against local hydrology and regulation, then adapt.

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Key Data at a Glance

Parameter	Detail
Document	FEMA P-259: Engineering Principles and Practices for Retrofitting Flood-Prone Residential Structures
Publisher	FEMA (United States)
Previous edition	Third Edition, 2012 (and 2001 before that)
Target readers	Engineers, architects, local code officials
Building coverage	One- to four-family residences
Flood conditions covered	Flooding without wave action
Main objective	Break the cycle of repetitive flood damage (an NFIP objective)
Damage reduction (NFIP-compliant vs. older buildings)	65% less on average
Retrofit methods discussed	Elevation, relocation, dry floodproofing, wet floodproofing, levees and floodwalls
Updated edition content	Evaluation, planning, retrofit design, updated case studies
Related training	FEMA IS-280 course, about 1.5 hours

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Data Sources

Source	Detail
ASFPM (floods.org)	Announcement of the updated FEMA P-259 edition
Informed Infrastructure	October 2026 trends roundup
FEMA	IS-280 course page on the revised P-259
FEMA P-259 Third Edition (2012)	Previous document, reference for the method framework
University of Wisconsin Libraries	Synopsis of methods: elevation, relocation, floodproofing, levees/floodwalls
BASC / PNNL	Note that Third Edition cost estimates are outdated

This article is for informational and educational purposes. For design decisions, consult the official FEMA P-259 document and the technical and land-use regulations that apply at the project site.

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What has your experience been with retrofitting buildings in flood-prone areas? Share your thoughts in the comments below 👇

Hudson Tunnel TBM Starts Boring: The First New Rail Tunnel Under the Hudson River in 116 Years

civilciv, 2026

On October 8, 2026, a Tunnel Boring Machine (TBM) began cutting through the Palisades Cliffs in North Bergen, New Jersey marking the most significant engineering milestone in the Hudson Tunnel Project to date.    

After decades of planning, years of political battles, funding crises, and months of on-site preparation, the cutterhead of the first TBM finally bit into rock. The moment was confirmed by the Gateway Development Commission (GDC), which oversees the broader $16 billion Gateway Program.

The significance of the moment cannot be overstated. It had been nearly 120 years since the last train tunnel under the Hudson River was excavated. What is now beginning beneath New Jersey will become the first new rail tunnel under the Hudson River since 1910.

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Why the Hudson Tunnel Matters

To understand the scale of this project, you need to understand the problem it is solving.

The existing North River Tunnel built between 1904 and 1910 carries Amtrak intercity trains and NJ Transit commuter rail into New York Penn Station. It is the only rail link between New Jersey and Manhattan, handling hundreds of thousands of passenger journeys every single day.

The tunnel was severely damaged by saltwater flooding during Hurricane Sandy in 2012. Despite ongoing maintenance, the damage has steadily degraded the infrastructure. Engineers have long warned that the tunnel is operating well past its safe service life and that a sustained closure for repairs, which could take years, would be catastrophic for the entire Northeast Corridor rail network.

The Hudson Tunnel Project is the answer: a new two-tube rail tunnel that will allow the existing North River Tunnel to be taken out of service for rehabilitation, without interrupting rail service between New Jersey and New York.

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What Just Started: The Palisades Tunnel Package

The Gateway Development Commission has begun excavation of the Hudson Tunnel Project's new rail tunnel under the Hudson River, with its first tunnel boring machine starting work on schedule.

This initial phase known as the Palisades Tunnel Project package covers the first segment of the new tunnel on the New Jersey side of the river. The first TBM has begun boring the northern tube of the new tunnel, with a second machine set to begin operations in the coming weeks.

The two TBMs will excavate the parallel twin tubes of the new rail tunnel from the Tonnelle Avenue entrance in North Bergen, New Jersey, to an access shaft in Hudson County a distance of approximately 1.6 kilometres (5,100 feet) through hard, dry rock.

The first phase of tunnel boring is being led by Schiavone Dragados Lane JV as part of the Palisades Tunnel Project construction package.

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The Engineering Behind the TBMs

The TBMs used in this project are not off-the-shelf machines. They are massive, highly complex machines custom-built for the Hudson Tunnel Project by Herrenknecht one of the world's leading manufacturers of tunnel boring equipment.

Two distinct sets of TBMs have been designed for the project, each optimised for a different type of ground condition:

Set 1 — Rock TBMs (Currently Boring)

These machines are designed to tunnel through the hard, dry rock of the Palisades Cliffs on the New Jersey side. The cutting head bores through solid basalt and diabase among the hardest rock types found in the region, with compressive strengths exceeding 200 MPa.

Set 2 — Mixed Ground TBMs (To Follow)

The second TBM pair is optimised for "mixed ground conditions" (mostly soft silt) under the Hudson River and will build the stretch of the tunnel tubes from New Jersey to Manhattan. These machines face an entirely different challenge: maintaining a pressurised face to prevent water infiltration as they bore through the riverbed sediment beneath the Hudson.

Boring Rate and Timeline

Each TBM can install approximately 9 metres of lined tunnel per day. Accounting for planned pauses for maintenance and cutterhead replacement, the first 1.6 kilometres of both tubes is expected to take approximately one year to complete once boring begins.

This means the Palisades section alone just the New Jersey approach will take the better part of 2027 to complete. The full tunnel, stretching under the Hudson River to Manhattan, will require the handoff to the second pair of mixed-ground TBMs and several more years of excavation.

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A Project That Nearly Didn't Happen

The start of boring on October 8 is not just an engineering milestone it is a political one.

In October 2025, amid a federal government shutdown, funding for the Gateway Project stopped flowing despite a previous $12 billion commitment made under the Biden administration.

The project faced an existential threat. Years of work, billions in prior investment, and the manufacturing of custom TBMs were all at risk of being wasted. State and federal officials alongside advocacy groups, rail operators, and engineering organisations mounted a sustained campaign to restore funding and keep the project alive.

That effort succeeded. "We fought and beat efforts from the administration to halt the Gateway project and today, that dream becomes a reality," said New York Governor Kathy Hochul at the ceremonial launch on September 28, 2026.

The start of actual boring on October 8, confirmed on schedule represents the point at which the project became truly irreversible. TBMs don't stop once they start without enormous cost and consequence. The Hudson Tunnel Project is now underway in the most tangible sense possible.

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The Broader Gateway Program: Ten Construction Packages

The Hudson Tunnel Project is itself part of the larger Gateway Program a comprehensive modernisation of the rail infrastructure connecting New Jersey and New York. The broader project is divided into ten distinct construction packages, with further tunnelling operations to follow after the completion of this critical first stage.

No.	Package	Status
1	Palisades Tunnel (NJ approach)	Underway, TBM boring through hard rock
2	Hudson County Access Shaft	Concurrent with Palisades package
3	Under-river tunnel (NJ side)	Mixed-ground TBMs to follow
4	Under-river tunnel (NY side)	Same TBM set continuing under the river
5	Manhattan approach	Connection to Penn Station infrastructure
6	Penn Station improvements	Platform and capacity upgrades
7	North River Tunnel rehabilitation	Once new tunnel is in service
8	Signal and systems upgrades	Modern CBTC signalling throughout
9	Portal Bridge replacement	Swing bridge over Hackensack River, NJ
10	Electrical and mechanical systems	Power, ventilation, fire suppression

The sheer scale of the Gateway Program means this TBM start as monumental as it is represents only the beginning of what will be more than a decade of major engineering works.

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What This Means for Rail Engineering

From a civil and geotechnical engineering standpoint, the Hudson Tunnel Project is one of the most technically complex urban tunnelling projects currently underway anywhere in the world.

The Geology Challenge

The Palisades Cliffs are composed of extremely hard igneous rock basalt and diabase with compressive strengths exceeding 200 MPa. This is some of the hardest rock TBMs regularly encounter in urban environments. Cutterhead wear rates will be high, requiring planned maintenance interventions throughout the boring process.

The Ground Transition Challenge

Moving from hard rock to the mixed silt and sand conditions beneath the Hudson River requires not just different machines, but different engineering disciplines from hard rock mining to pressurised face tunnelling with full slurry or earth pressure balance management. The interface between the two ground types will require meticulous engineering management.

The Urban Environment Challenge

The Manhattan approach tunnel passes beneath some of the most densely built urban real estate on the planet. Settlement monitoring, vibration management, and utility protection will be critical as the second pair of TBMs eventually approaches the New York side.

The Global Precedent

When complete, the Hudson Tunnel will demonstrate that century-old critical infrastructure beneath one of the world's busiest urban corridors can be supplemented and rehabilitated without interrupting service a model with profound implications for aging tunnel infrastructure in cities worldwide.

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Complete Technical Data

Parameter	Detail
Project	Hudson Tunnel Project (part of Gateway Program)
Total project value	$16 billion
TBM boring start	October 8, 2026
Ceremonial launch	September 28, 2026
First phase location	North Bergen, NJ (Palisades Cliffs)
First phase length	~1.6 km (5,100 ft) per tube
Ground type — Phase 1	Hard rock (basalt and diabase)
Rock compressive strength	>200 MPa
Ground type — Phase 2	Mixed ground / river silt
TBM manufacturer	Herrenknecht (Germany)
First phase contractor	Schiavone Dragados Lane JV
TBM boring rate	~9 metres of lined tunnel per day
Phase 1 duration	~1 year per tube
Number of TBM sets	2 (rock TBM + mixed ground TBM)
Tunnel type	Twin-tube rail tunnel
Last Hudson tunnel built	1910 (North River Tunnel)
Years since last tunnel	116 years
Project oversight	Gateway Development Commission (GDC)
Total construction packages	10 packages
Daily passengers (existing tunnel)	Hundreds of thousands per day
Damage trigger event	Hurricane Sandy, 2012
Funding crisis	October 2025 (federal government shutdown)
Prior federal commitment	$12 billion (Biden administration)

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5 Engineering Lessons from the Hudson Tunnel Project

1. Political resilience is an engineering requirement No amount of engineering excellence can deliver a project that loses its funding. The Hudson Tunnel Project nearly collapsed in 2025 due to political decisions. Engineers and project leaders must understand that project delivery increasingly requires the ability to navigate political environments, not just technical ones.

2. Custom TBMs are worth the investment The decision to commission purpose-built, ground-condition-specific TBMs from Herrenknecht rather than adapting existing machines reflects a mature understanding of what the project required. One machine type cannot efficiently bore through both 200 MPa basalt and soft river silt. The right tool for the right ground saves time and money over the project lifecycle.

3. Package-based delivery manages complexity Dividing a project of this scale into ten distinct construction packages allows different contractors with specific expertise to work on different elements, potentially in parallel. It also reduces the risk that delays in one element cascade through the entire project timeline.

4. Phased boring sequences require careful handoff planning The transition between the Phase 1 rock TBMs and the Phase 2 mixed-ground TBMs at the Hudson County Access Shaft is one of the most critical engineering interfaces in the project. Getting this handoff right, including the extraction of the first TBM set and the launch of the second, will be a defining moment in the project's delivery.

5. Aging critical infrastructure is a global challenge The North River Tunnel is one of thousands of critical infrastructure assets worldwide operating beyond their original design life. The Hudson Tunnel Project is one of the few places where a viable, funded solution is now actually being built. The model it establishes new tunnel alongside existing, then rehabilitation will be studied by infrastructure owners globally.

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What Comes Next

With the first TBM now boring on schedule, the immediate milestones to watch:

• Second TBM launch, expected within weeks, boring the southern tube of the Palisades section
• Palisades section completion, approximately 12 months after boring start for each tube
• Hudson County Access Shaft completion, parallel workstream to Phase 1 boring
• Launch of mixed-ground TBMs, to begin the under-river section toward Manhattan
• First new rail service in the new tunnel, still several years away, but now firmly on track

GDC CEO Tom Prendergast said: "When the first tunnel boring machine's cutterhead bit into the rock face in the launch box, GDC reached the most significant Hudson Tunnel Project delivery milestone to date on schedule. This is a major achievement that would not have been possible without the hundreds of people who have worked together to plan, design, and build the infrastructure and equipment needed for this incredible machine to do what it was made to do."

After 116 years, the Hudson River is about to be tunnelled again. And this time, it's happening on schedule.

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Data Sources

Source	Detail
Gateway Development Commission	Official statement, October 8, 2026
Trains.com	TBM boring report, October 8–9, 2026
World Construction Network	Excavation update, October 9, 2026
Railway Age	Ceremonial launch report, October 2026
NJ Biz	Palisades Cliffs drilling photos & update
New Civil Engineer	Herrenknecht TBM manufacturing report, August 2025
ROI-NJ	TBM readiness update, December 2025

All technical figures reflect the project specification as of the start of Phase 1 boring, October 8, 2026.

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What aspects of the Hudson Tunnel Project's engineering do you find most compelling? Drop your thoughts in the comments below 👇

55,000 Tonnes of Rock: Inside the UK's Biggest Breakwater Reinforcement Project of 202

South Gare breakwater reinforcement
55,000 tonnes Norwegian granite installation, River Tees UK 2026

A 150-year-old structure. A storm that nearly broke it. And an engineering response that will define coastal infrastructure protection for decades to come.

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On the Yorkshire coast of England, where the River Tees meets the North Sea, one of the most significant coastal engineering projects in the UK is now underway.

PD Ports has officially commenced a multi-million-pound programme to reinforce the South Gare breakwater a historic structure that has protected safe navigation into the River Tees for more than 150 years. The scale of the works is staggering: 55,000 tonnes of high-density granite rock, sourced from Norway, will be placed around the breakwater's base across two phases stretching into summer 2027.

For civil and coastal engineers, this project is a masterclass in resilience engineering and a case study in what happens when century-old infrastructure meets the accelerating reality of climate change.

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What Is South Gare and Why Does It Matter?

South Gare is a man-made breakwater located at the mouth of the River Tees, near Redcar in the Northeast of England. Originally constructed over 150 years ago, it serves as the primary protective structure for Teesport one of the UK's largest and busiest ports and the wider river navigation channel.

Every day, thousands of vessels pass through the protection it provides. Millions of tonnes of cargo move through Teesport annually, supporting businesses, jobs, and investment across the entire Teesside region. Without South Gare, safe navigation into the river would be significantly compromised.

For over a century, this structure has silently done its job, withstanding the relentless force of North Sea storms. Until October 2023.

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The Trigger: Storm Babet and the Wake-Up Call

In October 2023, Storm Babet struck the Yorkshire coast with devastating force. The breakwater at South Gare sustained significant damage a stark reminder of just how vulnerable even the most robust coastal infrastructure can be when exposed to increasingly extreme weather events.

Remedial repairs were completed in the months following the storm. But PD Ports recognised that reactive maintenance alone was no longer sufficient. With climate projections indicating that storms of similar or greater severity will become more frequent in coming decades, a long-term structural solution was needed.

That decision triggered 18 months of intensive engineering work.

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18 Months of Research Before a Single Rock Was Placed

What makes this project particularly noteworthy is the depth of pre-construction investigation that preceded it.

PD Ports engineers, alongside specialist contractors, conducted comprehensive surveys of the breakwater including dive surveys and bathymetric mapping to fully understand the structure's construction, condition, and how wave energy impacts it across different storm scenarios.

The result was a reinforcement concept built around one core principle: place high-density rock around the breakwater's base to absorb and dissipate wave energy before it reaches the existing structure.

But before a single rock was placed in the North Sea, the design had to be proven.

Physical Modelling at HR Wallingford

The engineering team commissioned physical hydraulic modelling at HR Wallingford in Oxfordshire one of the world's leading centres for coastal and maritime engineering research.

A 1:50 scale model of the South Gare breakwater was constructed and subjected to simulated storm conditions equivalent to a one-in-200-year event among the most extreme scenarios engineers plan for in coastal infrastructure design.

The testing replicated the impact of a 9.2-metre high wave comparable in height to three double-decker buses stacked on top of each other. Only after the design demonstrated it could withstand conditions of this magnitude did the project move into the construction phase.

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The Engineering Solution: What's Actually Being Built

The project is structured in two phases:

Phase 1 : September/October 2026 (Currently Underway)

• Approximately 15,000 tonnes of high-density Norwegian granite installed around the breakwater base
• Rocks measure up to 2.5 metres in diameter and weigh up to 30 tonnes each
• Placed predominantly below the waterline using a specialist installation barge
• Contractors: McLaughlin & Harvey, working alongside marine specialist Herbosch-Kiere
• Each rock is meticulously positioned to maximise wave energy absorption

Phase 2 : Summer 2027

• A further 40,000 tonnes of rock to be installed
• Completes the full armour layer around the base of the structure
• Total combined installation: 55,000 tonnes

The rocks are designed not to simply block wave energy, but to absorb and dissipate it a critical distinction in coastal engineering. By placing the armour layer predominantly below the waterline, the design intercepts wave energy at its source, reducing the load transferred to the existing structure above.

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Why Norwegian Granite?

The specification of high-density Norwegian granite for this project is not arbitrary. Coastal armour rock must meet stringent requirements:

• High density - to resist displacement by wave action without requiring anchor systems
• Durability - to withstand continuous saltwater exposure and mechanical abrasion from wave impact
• Consistent quality - to ensure predictable structural behaviour across 55,000 tonnes of material
• Specific shape characteristics - individual rocks must interlock effectively to create a stable armour layer

Norwegian granite quarries are among the most consistent sources of high-quality, high-density coastal armour rock in Europe, which explains why the material is being shipped thousands of kilometres to the Yorkshire coast for this application.

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The Bigger Picture: Why This Project Matters Beyond Teesside

The South Gare project is significant not just for the River Tees, but as an indicator of where coastal infrastructure engineering is heading globally.

Climate Change Is Rewriting the Design Brief

For generations, coastal structures were designed based on historical storm data. The assumption now widely challenged was that the past was a reliable guide to future conditions.

Storm Babet in 2023 was a direct consequence of the changing climate. As ocean temperatures rise and atmospheric energy increases, storm intensity and frequency are both increasing. Coastal infrastructure designed to 1970s or 1980s standards is increasingly being exposed as underspecified for the conditions it now faces.

The South Gare project responds to this directly. The one-in-200-year event standard used in the HR Wallingford testing reflects a much more conservative design philosophy than the one that governed the original construction. It is, in effect, future-proofing a historic structure for a climate that its original designers could not have anticipated.

The Cost of Doing Nothing

The economic case for this investment is straightforward. Teesport handles millions of tonnes of cargo annually. Any disruption to safe navigation whether from a damaged breakwater or a storm-related closure carries substantial economic consequences for businesses and supply chains across the region.

The multi-million-pound investment in South Gare reinforcement is, in economic terms, an insurance policy on an asset whose operational value is orders of magnitude larger than the cost of protecting it.

A Model for Ageing Coastal Infrastructure Worldwide

South Gare is not unique in its vulnerability. Coastal ports and harbours around the world were built in the 19th and early 20th centuries, using materials and to standards that reflect the engineering knowledge and climate assumptions of their era. Many are now facing the same reckoning that Storm Babet forced at South Gare.

The approach taken here comprehensive survey, physical modelling, phased rock armour installation offers a replicable framework for coastal infrastructure owners grappling with the same challenge elsewhere.

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Key Engineering Facts at a Glance

Parameter	Detail
Structure	South Gare breakwater, River Tees, UK
Structure age	150+ years
Trigger event	Storm Babet, October 2023
Project owner	PD Ports
Main contractors	McLaughlin & Harvey / Herbosch-Kiere
Phase 1 rock volume	~15,000 tonnes (Sep/Oct 2026)
Phase 2 rock volume	~40,000 tonnes (Summer 2027)
Total rock volume	55,000 tonnes
Rock type	High-density Norwegian granite
Individual rock size	Up to 2.5m diameter / 30 tonnes
Design test standard	1-in-200-year storm event
Wave height tested	9.2 metres
Testing facility	HR Wallingford, Oxfordshire (1:50 scale model)
Placement method	Specialist installation barge, below waterline

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What Civil Engineers Can Learn From This Project

1. Invest in pre-construction investigation, The 18 months of surveys, modelling, and design work before construction began is not overhead, it's the difference between a solution that performs and one that fails. Physical modelling at HR Wallingford provided confidence that the design would work before a single tonne of rock was placed in the sea.

2. Design for future conditions, not past ones, The one-in-200-year event standard used here reflects a fundamental shift in how coastal engineers must think about design life. Historical storm data is no longer a sufficient basis for long-term coastal infrastructure decisions.

3. Below-waterline protection is often more effective, Placing the armour layer predominantly below the waterline, where wave energy is greatest and the existing structure is most vulnerable, is a more efficient use of material than above-waterline visible armour. Energy dissipation before impact is always preferable to resistance after impact.

4. Phased delivery manages risk Splitting 55,000 tonnes of rock installation into two phases allows the project team to observe Phase 1 performance through a winter storm season before committing to the final design and volume for Phase 2. This is disciplined, evidence-based engineering.

5. Coastal infrastructure is economic infrastructure The South Gare project is a reminder that coastal protection structures are not just engineering assets, they are enablers of entire regional economies. The investment calculus must include the economic cost of failure, not just the construction cost of protection.

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Final Thoughts

As Paul Foreman, CEO of PD Ports, put it: "These are the largest works carried out on the breakwater since it was originally constructed more than 150 years ago. Our aim is not only to protect the structure today, but to ensure it continues to perform its vital role well into the future."

That sentence captures the essence of what resilience engineering is about in 2026. Not just fixing what is broken. Not just meeting today's standards. But anticipating tomorrow's conditions and building infrastructure that will still be performing its vital role when the next generation of engineers inherits it.

South Gare has protected the River Tees for 150 years. With 55,000 tonnes of Norwegian granite and the best physical modelling available, the goal is to protect it for 150 more.

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Data and project details sourced from PD Ports official announcements, Teesside Live, Port Strategy, and New Civil Engineer (September 2026). All figures reflect the project specification as of the commencement of Phase 1 works.

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What's your take on this project? How does your region approach ageing coastal infrastructure reinforcement? Share in the comments below 👇