CSX Inaugurates Double-Stack Rail Service Through the Historic Howard Street Tunnel in Baltimore

Published: June 25, 2026

A transformative infrastructure project removes a decades-old bottleneck, boosting the Port of Baltimore’s competitiveness and enhancing East Coast freight efficiency.

In a major milestone for American freight rail, CSX has begun operating double-stack intermodal trains through Baltimore’s historic Howard Street Tunnel. The first revenue double-stack train passed through the 1.7-mile tunnel in the early hours of May 5, 2026 (around 12:15 a.m.), following the tunnel’s expansion and reopening in September 2025.

Officials celebrated the achievement at the Port of Baltimore in mid-to-late June 2026, marking the completion of clearance improvements across the corridor. This development eliminates the last major obstacle to seamless double-stack service along CSX’s vital I-95 rail corridor between Baltimore and Philadelphia (and ultimately connecting broader East Coast networks).

Warren Calloway photo.

Background: A 130-Year-Old Bottleneck

The Howard Street Tunnel, originally constructed between 1890 and 1895 by the Baltimore & Ohio, runs beneath downtown Baltimore and has long served as a critical link in the region’s rail network. However, its vertical clearance fell short of the approximately 21 feet needed for double-stacked shipping containers (two high on specialized flatcars). It was up to 18 inches too low, creating a persistent chokepoint.

For more than 50 years, planners discussed solutions. Double-stack trains could not pass through, forcing containers to travel single-stacked or be transferred to trucks, which increased costs, highway congestion on I-95, and emissions.

The tunnel project formed the centerpiece of a broader Howard Street Tunnel Clearance Program (also called the HST Project). This initiative addressed vertical clearance restrictions at 22 locations across Maryland, Delaware, and Pennsylvania to enable full double-stack operations to and from the Port of Baltimore’s Seagirt Marine Terminal and Intermodal Container Transfer Facility (ICTF).

Project Scope, Timeline, and Engineering Achievements

The overall effort was a major public-private partnership involving CSX (the project sponsor), the Federal Railroad Administration (FRA), U.S. Department of Transportation, the State of Maryland, and the Commonwealth of Pennsylvania. Total costs were reported in the range of approximately $450–566 million, with notable federal contributions (including $125 million cited in some announcements).

Key elements included:

Major reconstruction inside the Howard Street Tunnel itself (track lowering by about 18 inches, new tunnel lining, improved drainage systems, structural reinforcements).
Track lowering and bridge modifications/replacements at numerous other sites (e.g., Guilford Avenue Bridge, North Avenue, Harford Road, and locations in Wilmington, DE, and Philadelphia suburbs).

Timeline highlights:

Environmental approvals and planning advanced through 2021 (FONSI issued June 2021).
Early construction began in Pennsylvania in 2022.
The tunnel closed to rail traffic on February 1/5, 2025, for intensive 24/7 work lasting 233 days.
Tunnel expansion completed and reopened ahead of schedule on September 26, 2025.
Additional corridor clearances finalized progressively; full double-stack readiness achieved by spring/early summer 2026.
First revenue double-stack train through the tunnel: May 5, 2026.
Official commemoration at the Port of Baltimore: around June 22–23, 2026.

During the tunnel shutdown, crews removed over 25,000 cubic yards of material, installed extensive drainage (14,000+ linear feet of wall drains), placed significant concrete and grout, and performed other complex work in a constrained urban environment beneath a major city.

The project earned recognition as one of Railway Track & Structures’ Top Projects for 2026.

What Double-Stack Service Means

Double-stacking allows two shipping containers to be stacked vertically on a single railcar, roughly doubling the cargo capacity per train compared to single-stack operations. This is far more efficient than moving the same volume by truck.

Key benefits include:

Increased capacity for the Port of Baltimore — approximately 160,000 additional containers per year.Stronger competitiveness with ports like Norfolk and New York/New Jersey.
Reduced highway congestion and truck traffic along the busy I-95 corridor.
Lower emissions and environmental advantages (rail is significantly more fuel-efficient per ton-mile than trucking).
Economic stimulus: estimates include more than 1,000 new jobs directly, broader supply-chain job growth (some projections cited up to several thousand), and roughly $1 billion in annual economic activity.

CSX President and CEO Joe Hinrichs noted the project as “a once-in-a-generation achievement that will drive commerce, jobs, and growth across Maryland and the East Coast for decades.”Maryland Governor Wes Moore emphasized its role in supporting small businesses through a stronger supply chain.U.S. Senator Chris Van Hollen highlighted how larger cargo loads mean more ships calling at the port, more handling jobs, and ripple effects throughout the economy.

Stakeholder Perspectives and Broader Impact

The project enjoyed strong bipartisan support across multiple governors, port directors, and federal administrations. International Longshoremen’s Association Local 333 President Scott Cowan called it “tremendous and a long time coming,” praising the collaborative effort.

CSX highlighted how the upgrade removes the final volume constraint on its I-95 corridor, enabling the fastest and most efficient freight rail route from Florida to the Northeast and unlocking greater lane-conversion opportunities (shifting freight from trucks to rail).

Partial double-stack access to the northern portion of the Port of Baltimore was achieved earlier (around late 2024) via other clearance work north of the tunnel. Full bidirectional double-stack service through the tunnel and corridor marks the complete realization of the program’s goals.

Looking Ahead

With the Howard Street Tunnel now cleared for double-stack service, the Port of Baltimore and CSX’s East Coast network are positioned for significant growth. The improvements support expanded intermodal traffic to Midwest markets and strengthen supply-chain resilience.

The project demonstrates the power of sustained public-private investment in aging infrastructure. It modernizes a 130-year-old asset while delivering tangible economic, environmental, and operational returns for decades to come.

As one official put it during the celebrations, this long-sought upgrade has removed the “Achilles heel” of the Port of Baltimore — and opened a new chapter for efficient freight movement along one of America’s most important corridors.

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