Photo essay: A peek inside CSX's unusual Howard Street Tunnel project 

By Jeff Stagl, Managing Editor 

CSX continues to post progress with the more than $500 million Howard Street Tunnel project in Baltimore. The undertaking involves 10 projects designed to address 21 obstructions in and around the area that have prevented the Class I from operating double-stack intermodal trains to and from the Port of Baltimore. 

Five of the projects have been completed while the other five — including the massive reconstruction of the tunnel — are under construction and scheduled for completion either by year’s end or in early 2026. The cost of the tunnel work alone is about $300 million. 

The project is being funded through one of the largest public-private construction partnerships in Maryland’s history. The states of Maryland and Pennsylvania, city of Baltimore and CSX are contributing millions of dollars for the work, which also will be funded in part by a Federal Railroad Administration grant. 

Situated 40 feet below surface level, the tunnel is divided into a concrete box, a cut-and-cover and a mined tunnel section. The combination of the three sections presents a unique construction challenge since diverse methods were used to build the tunnel 130 years ago. The reconstruction will increase the tunnel’s lifespan to 75 years. 

After the project is completed, CSX’s vital Interstate 95 corridor will be completely cleared for double-stack traffic between Baltimore and Philadelphia, as well as from the Port of Baltimore’s Seagirt Marine Terminal intermodal facility to consumer markets in the Midwest. 

On March 25, RailPrime Managing Editor Jeff Stagl toured the tunnel and a few nearby project sites with several CSX engineering executives. In addition to the image posted at the top of the page, the following are some photos he took and information he gleaned during the tours. 

The tunnel ‘s current clearance is 18 inches short of what’s needed to accommodate double-stack trains. Soil is being excavated to drop the ground level by about two feet throughout most of the tunnel.

CSX and its design-build contractor Skanksa/Fay S&B USA Construction are using a gantry system tailored for the project to bring materials — such as track panels and concrete slabs — to work sites.

Shown: As of March 25, crews had completed foundation/slab work about 700 feet into the tunnel. An excavator is positioned to remove more soil.

Precast concrete inverted slabs are being installed throughout the tunnel to support the track by helping to optimize load-bearing requirements. The project requires more than 200 of the 20-foot slabs. Overall, more than 7,100 feet of new precast concrete flooring will replace the aged tunnel invert floor and the brick beneath the old track.

Dozens of crew members are needed to advance work in the tunnel 24/7. There typically are two 12-hour shifts scheduled per day.

As trains depart the tunnel, they pass through a canopy of the former Mount Royal Station passenger depot, which was completed in 1896. Located off Howard Street, the facility now is owned by the Maryland Insitute College of Art.

CSX is targeting completion of all work in the tunnel by sometime in November. The tunnel was extended in the 1980s.

One of the other four clearance projects in addition to the tunnel reconstruction calls for extending double track and building new track to accommodate double-stack trains. The work also includes drainage and retaining wall improvements.

Workers completely removed all existing track so the corridor could be excavated and prepped for new track. The contractor for the project — which is located several miles from the tunnel — is Polivka International.

Some bridges and overhead structures will be reworked or rebuilt as part of the track reconstruction work.