WASHINGTON, D.C. — Amtrak will shut down A-Interlocking for nine days from October 16 through October 26, 2026. The closure requires passengers traveling between Virginia and Washington to use alternate transportation during the outage.

A-Interlocking is located in the First Street Tunnel just south of Union Station. Every Amtrak train traveling south from Washington passes through this critical junction.

"Every train that comes through D.C. that’s traveling south goes through A-Interlocking," said Greg Michalski, Amtrak’s deputy chief of production construction. The shutdown is intended to replace rail infrastructure that has reached the end of its useful life.

"We’ve been doing maintenance throughout the last couple years to maintain the tunnel, and all these assets have just reached their useful life span. They’re at the point of a complete replacement," Michalski said. The existing switches and crossovers are beyond their service life, requiring a 10-mph speed restriction that impacts operations.

Workers will rehabilitate the tunnel track base during the outage. The work requires removing a significant section of track, making it impossible for trains to operate through the junction during the shutdown.

"There will be no tracks to actually physically run a train on," Michalski said. Amtrak says much of the new track will be assembled and tested before crews start tearing out the old infrastructure.

Amtrak plans to keep crews working 24 hours a day for the nine days until the project is complete. "We’re going to work 24 hours for the nine days, 24/7 for the nine days until the project’s done," Michalski said.

The outage will affect Virginia Railway Express service. VRE will continue operating, but Union Station will not be a destination during the outage.

DJ Stadtler is the Executive Director of the Virginia Passenger Rail Authority. "During this period, you will not be able to take a train from Virginia into D.C." Stadtler said.

"We totally understand it’s an inconvenience. We don’t love it either, but we’re going to make sure folks have the options to get where they want to go when they want to get there," Stadtler said. Some trains will terminate in Alexandria, where riders can transfer to Metrorail.

Additional bus service will connect passengers from points across Virginia. Some riders may have to catch a bus to places like Richmond and Roanoke. Amtrak said it will support customers with rebooking options and alternative travel solutions.

Why It Matters

The shutdown affects a critical chokepoint for rail traffic between Washington, D.C. and Virginia. Because every southbound Amtrak train passes through A-Interlocking, the complete removal of track sections necessitates a total suspension of service through the tunnel. This infrastructure replacement addresses assets that have exceeded their service life and currently impose operational speed restrictions.

Travelers must rely on alternate transportation modes, including buses and Metrorail transfers, to navigate the gap in rail service. The Virginia Passenger Rail Authority acknowledges the disruption but emphasizes the provision of alternative options for passengers. The nine-day timeline reflects the scope of replacing major components such as double-slip switches and track diamonds while rehabilitating the tunnel base.

Timeline

On April 28, 2025, the FRA published a notice of availability and request for comments about the request for amendment (RFA) that the National Railroad Passenger Corporation (Amtrak) submitted regarding its Positive Train Control System.

During the outage beginning October 16, 2026, crews will replace two double-slip switches and a rail crossing known as a diamond. Workers will rehabilitate the tunnel track base, and Amtrak will install new electric switch machines, replace ballast beneath the tracks, and address drainage issues in the tunnel. VRE will continue operating, but Union Station will not be a destination during the outage, and some riders may have to catch a bus to places like Richmond and Roanoke.