Amtrak said limited train service between Philadelphia and New York should resume on Monday, with full service by Tuesday.
Amtrak has had to modify Northeast Corridor service because of the deadly derailment in Philadelphia.
Two of the three people killed when their vehicle was hit by an Amtrak train in Mansfield earlier this week were identified Wednesday.
Three people died after an Amtrak train hit a truck on the tracks overnight in Mansfield.
The new engines will be used on the Northeast Corridor between Washington, D.C., and Boston and on Keystone Corridor trains that run between Philadelphia and Harrisburg, Pa.
Amtrak and the Commuter Rail service has been restored after a trespasser was hit and killed on the tracks.
Amtrak is introducing a pilot program to notify Northeast Corridor passengers about major service disruptions via Twitter.