Trolley, track and bridge construction will shut down Amtrak, Coaster and freight service from Oceanside to San Diego throughout the weekend.
The scheduled closure will begin just after midnight on Friday and continue through Monday morning at 5 a.m.
Amtrak, the North County Transit District and Metrolink will be providing bus service to accommodate passengers.
Construction crews are installing a second track to improve commuter rail service, working on the Mid-Coast Trolley extension, and making improvements to the San Diego River Bridge near Friars road.
SANDAG has routinely scheduled weekend rail closures in recent months to complete this work.
Regular passenger rail service is scheduled to resume in time for the morning commute on Monday.