The Amtrak derailment outside Philadelphia on Tuesday's has focused attention on a safety measure called "Positive Train Control."
The automated system takes control of trains if the engineer does not respond to changes in the speed of a train as it passes certain points. It's a complicated system that involves technology along the tracks and on the train.
After a rail system crash in California in 2008 outside Los Angeles, the federal government required the computerized upgrade be in place by the end of 2015.
Funding was not included in the project.
Federal officials have ordered Amtrak to expand use of a speed-restriction system in the area outside Philadelphia and analyze other areas with similar track designs and curves. The Federal Railroad Administration issued a similar order to Metro-North after the fatal derailment in 2013.
In the New York City area, "Positive Train Control" became a familiar industry term 2013. The fatal derailment of the Metro-North train in Spuyten Duyvil in the Bronx could have been prevented, officials from the federal and state governments said, with the positive-train control technology that can stop a train if the speed is not decreased.
MTA says in 2014, Metro-North installed automated detectors at 10 critical curves and moveable bridges. Those locations, according to the railroad's media representatives are: curves near theBridgeport, Port Chester, Spuyten Duyvil, White Plains, and Yonkers; and New Haven Line bridges near Cos Cob, Devon, Milford, South Norwalk, and Westport.
The LIRR reports, in its May monthly meeting agenda, that all critical curves were completed as scheduled by March 2014. Those specific locations were not provided.
Metro-North and LIRR also have been performing radar observations.
Amtrak has been adding positive-train control technology to the the Northeast Corridor, but it was not available on this section of line outside Philadelphia. Amtrak officials have said they added it to the most heavily traveled areas along the line and it will be in place along the Northeast Corridor by the end of 2015.
It is in place between Boston and New Haven and along sections connecting Washington and Baltimore.
The MTA is working to bring it to the LIRR and Metro-North by 2018. The estimated cost is nearly $1 billion. In April, the Federal Railroad Administration approved a loan of $967 million to the MTA to pay for the project. The MTA Board agreed to the re-payment plan and a news release calls it the "lowest-cost financing" available.
A spokesperson says the NYC Subway system has a different signal system. Higher speeds would trigger the halting of subway trains.