Two high-speed Amtrak trains back on track

WASHINGTON (CNN) -- Inspectors judged five of Amtrak's high-speed Acela trains fit to carry passengers Wednesday after at least 11 others were found to have potentially dangerous cracks near the trains' shock absorbers.

Amtrak allowed two trains and their cars to resume runs among Washington, Boston, Massachusetts, and New York, and three other trains are scheduled to resume service Thursday. The rest of the schedule for the Acela Express remained canceled.

Older Metroliner trains have been deployed to cover the Acela schedule at slower speeds since Tuesday when Amtrak temporarily canceled most high-speed service in the busy Northeast Corridor.

Periodic maintenance inspections Monday had revealed fractures where the yaw damper -- a type of shock absorber -- is mounted. The device cushions and controls the side-to-side motion of the train, Amtrak said in a written statement.

The failures were described as ranging from small cracks to larger fractures in the stainless steel brackets, officials said. Sixteen of the 18 Acela trainsets had been inspected by Wednesday afternoon, Amtrak said.

The Acela train has been having trouble maintaining an on-time schedule because of mechanical problems. Introduced in 2000, the bullet train reduces the Washington-New York trip by 15 minutes and the New York-Boston run by about 45 minutes.

Amtrak officials have warned of a need for improvements to the tracks along the Northeast Corridor, saying the condition of the rail system restricts speed and can aggravate mechanical issues.

The Acela trains are breaking down so frequently that Amtrak this month reduced the use of them until the manufacturer can make modifications, Amtrak spokeswoman Karen Dunn told CNN Financial News.