Many Amtrak trains in the region were canceled or delayed Tuesday and some Maryland commuter rail stations north of Baltimore were closed throughout Tuesday morning after overhead electrical wires came down south of Aberdeen.

Amtrak is still investigating why the wires came down on the tracks at about 2:30 a.m., Amtrak spokeswoman Danelle Hunter said.

Amtrak resumed partial service between Washington and Wilmington, Del., around 9:15 a.m. and full service at 12:15 p.m., Hunter said. Crews continued to work on the catenary system through the afternoon, but getting two of three tracks reopened near Aberdeen allowed full service to resume, she said.

Amtrak trains were delayed 30 to 90 minutes throughout the morning, Hunter said. She said they continued to face minor delays between Wilmington and Washington as trains traveled more slowly through the areas where workers were still making repairs.

The Aberdeen and Perryville stations serving Maryland Area Regional Commuter (MARC) trains on the Penn Line remained closed throughout the morning, forcing commuters to catch trains at Edgewood.

Terry Owens, a spokesman for the Maryland Transit Administration, said about 400 MARC passengers were affected by the station closings Tuesday morning.

MARC service was restored in time for the midday Number 520 northbound train from Washington to continue on to Aberdeen and Perryville. All afternoon and evening trains on northbound Penn Line were to travel all the way to Perryville as usual.

Hunter said Amtrak might not know the cause of the wire problem until later this week.