Securing Resiliency and Restoring Reliability on a Critical 18-Mile Rail Corridor Along the Gulf Coast

• Elevating a critical railway corridor track
• Building a retaining wall to prevent rail embankment erosion and overtopping
• Incorporating sustainability elements with recycled steel rail and used concrete ties for riprap
• Navigating an extensive environmental permitting process with various federal, state and local agencies
• Taking environmentally friendly measures to reduce the construction footprint on wetlands and marshes

The CSX NO&M Subdivision, running along the Gulf Coast from New Orleans to Mobile, Alabama, has long endured extreme weather events. An 18-mile section of the railroad route near the Louisiana and Mississippi border has been particularly prone to extended rail outages because of damage and coastal erosion from major hurricanes, costing CSX more than $164 million to restore service in just the last 20 years.

Following Hurricane Ida in 2021, CSX chose HDR to lead a redesign of the track roadbed to strengthen and reinforce this vulnerable segment to reduce embankment erosion, which provides a layer of protection to inland communities from rising flood water during storms and create staging areas to support construction and future storm recovery.

We provided CSX with an array of services, including track and structural design, coastal engineering support and environmental permitting services to help advance the project into one that restores consistency and reliability in this rail corridor.

Committing To Resiliency Through Design and Construction

The initial phase of the project is focused on hardening a 2-mile stretch of the CSX NO&M rail line, long exposed to damage from storm surge. The area is elevated above marsh, between Lake Catherine and Lake Borgne and has provided adequate protection to maintain rail service and hold back storm surge. But more extreme weather events have left the embankment vulnerable to overtopping and erosion from the impact of waves.

Our team included experienced coastal engineers who developed an impactful and resilient design for CSX to reinforce the 2-mile corridor. To address the risk of future flooding and sea level rise, the final design calls for elevating the areas of track to maintain 6-foot threshold above sea level throughout the corridor. A retaining wall revetment along the northern slope of the embankment will be built using repurposed steel rail to further protect against future water overtopping of the track. The steel rail pieces will be driven vertically into the ground to hold back a wall of riprap, supplemented by recycled concrete rail ties and other concrete debris for stability.

To support future construction, our team has designed staging areas and access points to provide space to make rail improvements. In the future, these areas will support CSX, allowing teams to improve their response to damage caused during storm events while providing deeper connectivity to remote portions of the land bridge.

Hardening and elevating the embankment along the remaining vulnerable rail section began in late 2024, with completion in 2029. As the project moves forward, our team is supporting CSX with the pursuit of additional funding sources, including through the Consolidated Rail Infrastructure and Safety Improvements Program.

Navigating an Environmentally Sensitive Area

Constructing the staging areas and rail embankment improvements required close coordination with various federal, state and local agencies to obtain necessary permits to move the project forward. Our team led the extensive environmental permitting process for CSX. Because of the railroad corridor’s proximity and direct impact to coastal waters, an emergency use authorization was needed to comply with the Clean Water Act. Additional necessary permits were sought and approved to authorize construction in the sensitive area. Additional measures were taken to balance the building of the wall and keeping waterways open to avoid disturbing the critical flow of salt water from the coast into the marshes.

The challenge of constructing in the unique terrain of the marsh will require the use of specialized equipment and experienced workers to properly perform work. When construction advances to later stages of delivery along the corridor, tools like a self-operating pile driver will be used to install retaining wall piles, lessening environmental impacts due to its small size and ability to be operated from the embankment.

Through these efforts, CSX is helping establish that what is ultimately designed and constructed not only preserves the coastal ecosystems and environment, but that the railway roadbed will continue to provide a sustainable mode of transport for more than 30 million gross tons of freight each year, and eventually, millions of people who rely on passenger rail service.