AlQa'dah 6, 1434, Sep 12, 2013, SPA -- U.S. passenger rail operator Amtrak suspended all train service between Philadelphia and Washington on Wednesday after overhead wires were damaged in northeastern Maryland, the company said. Engineers were assessing extensive damage to the wires that power the high-speed Acela Express and the Northeast Regional trains, and service may not be restored until Wednesday evening, said Amtrak spokesman Craig Schulz. The affected wires are in Elkton, Maryland. Amtrak is unsure what caused the damage. "Something got tangled up in the wires," Schulz said. In addition to the affected Amtrak trains, which carry almost a million passengers each month, all other trains that use the tracks are not operating between the two mid-Atlantic cities. Schulz said "dozens of trains" were affected, and passengers should expect lengthy delays. Initially, Amtrak suspended service between Baltimore and Wilmington, but the area was expanded to include Washington and Philadelphia.