An overheated axle part on one car triggered the derailment of a CSX freight train in Amsterdam, New York, on Oct. 12, the freight railroad announced on Friday.

The problem was with a part known as a journal, which acts like an axle bearing, said Meg Scheu, a CSX spokeswoman in Jacksonville, Fla. When the journal failed, 18 cars derailed before the train was brought to a stop, she said.

A separate investigation by the Federal Railroad Administration into the cause of the accident continues, said administration spokesman Steve Kulm, who said he could not comment on the railroad's findings because the federal probe is not complete.

Shortly before the accident, a wayside detector -- a piece of equipment along the tracks that detects abnormal heat levels on passing trains -- alerted the crew to a problem with the journal, Scheu said.

Wayside detectors are located at approximately 18-mile intervals along 22,000 miles of track within the CSX system, she said.

"The wayside detector did its job and the crew followed the operating procedures to stop the train," Scheu said. "Unfortunately, the train started to derail before it was stopped all the way."

Scheu said all rail cars would have been inspected before leaving Cincinnati for the trip to Selkirk, but journals are located inside the axles.

"This is a rare occurrence, but sometimes it does happen," she said. "That's what the wayside detectors are for."

Kulm said in October that the federal investigation would examine CSX's operating practices, signals, power and equipment in use at the time. Possible equipment issues were emerging as an early focus, he said.

No one was injured in the accident, which took place at 8:20 a.m. and shut down freight traffic and Amtrak passenger service west of Schenectady for more than a day.

The train included eight engines, 47 loaded cars and 31 empty cars.