William Rockefeller fell asleep at the controls of the Metro-North train that derailed in The Bronx.
A freight train derailed in Jamaica Wednesday afternoon.
The delivery was made in December and included the rail involved with last week's derailment.
A Federal Railroad Administration probe found that on-time performance was more important than safety.
The engineer woke up and tried to hit the brakes to stop the speeding train, sources said.
Investigators would not say if the cause of the crash was human error or mechanical malfunction.
Several lines were diverted Tuesday morning following Monday night's train derailment.
An LIRR train derailed about 9 p.m. near the Forest Hills station, an MTA spokesman said.
NJ Transit and Amtrak still had delays on Wednesday morning because of Tuesday's derailment; the 7 Train was not running express to Times Square because of mechanical problems.
A disabled New Jersey Transit train caused up to hour-long delays at Penn Station during rush hour Tuesday morning.
Long Island Rail Road customers continued to experience delays during the morning rush on Wednesday.
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