On Positive Train Control
It's been almost a week since the Philadelphia train derailment and people the question remains - would postive train control prevented the incident?
What is potive train control? The Federal Railorad Administation (FRA) defines it as: "Positive Train Control (PTC) systems are integrated command, control, communications, and information systems for controlling train movements with safety, security, precision, and efficiency." Its deployment is mandated in the Rail Safety Improvement Act of 2008 by December 31, 2105. There is still a ways to go.
PTC is an unprecedented technical and operational challenge. Since enactment of RSIA, railroads have devoted enormous human and financial resources to develop a fully functioning PTC system over the 60,000 miles that are subject to the PTC mandate. Progress to date has been substantial. Railroads have retained more than 2,400 signal system personnel to implement PTC and has already spent $5 billion on PTC development and deployment. Railroads expect to spend more than $9 billion before development and installation is complete.
A GAO report from 2013 outlines a number of challenges facing OTC roll out, echoing AAR's concerns about the complexity of the system and the timeline not being feasible.
The week before the Philadelphia derailment, the FRA also issued a research brief about PTC across shared networks that could be used by multiple railroads.
For more research about PTC you should go check out TRID.