By Paul Eckert
WASHINGTON (Reuters) - Train services were canceled and workers scrambled to protect power lines in Washington on Thursday as Hurricane Irene threatened the U.S. capital days after it was rattled by a rare earthquake.
Irene, a major Category 3 hurricane now battering the low-lying Bahamas in the Atlantic southeast of Florida, was expected to make landfall on Saturday in North Carolina, with its high winds raking the heavily populated mid-Atlantic seaboard where Washington and New York were vulnerable.
The 5.6 million residents in the Washington metropolitan area would be hit by heavy storms on Saturday and Sunday, warned weather forecasters and local officials. Irene was not expected to keep people away from work on Friday.
Mayor Vincent Gray used Twitter to urge residents to study emergency evacuation routes from Washington and tell them that the mostly low-lying city would make sandbags available.
The National Hurricane Center put the Washington metropolitan area and coastal Maryland to the east of the capital on hurricane watch for Sunday.
The dedication of a new Martin Luther King Jr. memorial on the National Mall that had been scheduled for Sunday was postponed because of the approaching storm. Organizers said the ceremony would be moved to September or October.
President Barack Obama plans to return to Washington on Saturday as planned from his vacation on the Massachusetts island of Martha's Vineyard, the White House said.
Virginia and Maryland, which border Washington, declared states of emergency, while local authorities ordered the mandatory evacuation of the beach resorts of Ocean City, Maryland, and Chincoteague, Virginia.
Electricity provider Pepco Inc said it had requested 600 emergency workers from other regions, and had already deployed 150 of them, to prepare for Irene's heavy rain and high winds that "could cause widespread and extended power outages."
The utility warned customers that restoring power "could be a multi-day event" and urged them to ensure adequate supplies of prescription medicines and infant supplies.
The Washington Metropolitan Transit Authority said it had prepared sandbags for flood-prone subway stations, inspected pumping facilities and called up extra staff for the weekend to prevent disruption to bus and subway services.
Railway operator Amtrak canceled trains operating south of Washington for Friday, Saturday and Sunday.
"Additional cancellations may be necessary in the coming days as the major storm moves north," Amtrak said.
Most schools in Washington had reopened on Thursday after being closed two days for safety inspections of 126 school buildings due a 5.8 magnitude earthquake on Tuesday. The quake was centered in Mineral, Virginia, about 90 miles southwest of Washington.
The largest quake in Virginia since 1897 caused damage to well-known buildings, including cracks to the top of the Washington Monument, a prime tourist attraction.
(Editing by Jackie Frank and Philip Barbara)