In 2008, President Bush signed the
Rail Safety Improvement Actinto law, setting new rules designed to prevent train accidents.
One of those measures required some railroads, to install positive train control (PTC) systems by the end of 2015.
The derailment of a Metro-North commuter train in New York on Sunday, which killed four people and injured dozens more, is precisely the sort of accident PTC should be able to prevent.
The engineer told investigators he “lost focus” before entering a sharp turn at 82 mph, way over the 30 mph speed limit.
Metro-North is one of the railroads required to implement PTC. Had it done so before this week, sensors would have noticed the excessive speed and slowed or stopped the train before the deadly crash.
The idea behind PTC is simple: A wireless communications network, track-side devices, and updated locomotives work together to automatically slow or stop a train before it derails or crashes.
Here’s an example of a PTC system from a report by the Congressional Research Service. (ETMS is Electronic Train Management System.)
Sensors, signals, and transponders are installed on existing track, and the network operating center sends information like speed limits to the train through those transponders. Updates on the train’s location are sent to the operating center as the locomotive passes the wayside signal switches.
Here’s a simpler view of the system, from the Association of American Railroads. The engineer controls the train, but PTC provides a warning if the train enters a zone where it needs to slow down.
The engineer would normally slow down before entering the brake zone:
But if he doesn’t, the train is equipped to do it automatically:
While the concept is simple, implementation is exceedingly complicated. The Rail Safety Improvement Act requires that PTC be installed on about 60,000 miles of track. Thousands of locomotives need to be modified. An enormous wireless communication network has to be built, along with tens of thousands of track-side devices. A lot of the required technology hasn’t even been fully developed yet, according to the Metropolitan Transportation Authority, which operates Metro-North.
It’s not going to be cheap, either. The Federal Railroad Administration (FRA) estimates getting the system up and running everywhere it’s mandated will cost $US14 billion. The always cash-strapped MTA says it has already budgeted $US600 million for installation, and the whole project will cost about $US900 million.
As a result, it’s an accepted fact that PTC won’t be in place everywhere by the 2015 deadline. An August 2013 report by the Government Accountability Office (GAO) summarized the problem nicely:
Most railroads report they will not complete PTC implementation by the 2015 deadline due to a number of complex and interrelated challenges. Many PTC components continue to be in various stages of development, and in order to ensure successful integration of these components, railroads must conduct multiple phases of testing before components are installed across the network.
Also, some railroads raised concerns regarding FRA’s limited staff resources in two areas: verification of field tests and timely certification of PTC systems. Commuter railroads face additional challenges such as obtaining radio frequency spectrum, which is essential for PTC communications.
GAO recommended Congress consider extending the deadline on some rail lines, and “approve the use of alternative safety technologies in lieu of PTC.”
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