Montgomery County, Maryland, fire officials believe a vehicle that burst into flames on CSX Transportation's Metropolitan Subdivision in Silver Spring early Tuesday morning was deliberately set ablaze.

Fire and rescue spokesman Pete Piringer says the vehicle caught fire about 04:30 EDT near the 8,600 block of 16th Street. Investigators are still trying to determine the exact cause of the blaze. The fire shut down CSXT's Metropolitan Sub and a stretch of MARC's Brunswick line between Rockville and Washington, D.C. until just before 07:00 EDT.

Although the stretch of track was reopened in the morning, a spokesman with the Maryland Transit Agency says MARC experienced delays through the morning as trains move through the area at limited speeds. Metrorail honored the tickets of MARC riders Tuesday morning.