Last Tuesday’s derailment of Amtrak train 188 in North Philadelphia happened on a stretch of track where a decades-old safety system had not been installed, even though the technology, known as automatic train control (ATC), was in place on the same segment for trains traveling in the opposite direction.
Experts say that ATC could have prevented the accident, which left eight passengers dead and injured more than 100. The decision not to install the technology on the northbound track where the wreck occurred seems difficult to reconcile with the tragic, 72-year legacy of that particular area of track, as well as with recent upgrades to the locomotives traveling those rails.
On Labor Day weekend 1943, the Pennsylvania Railroad’s Congressional Limited, an express train from Washington, D.C., to New York, derailed after an axle snapped on one of the passenger cars at Frankford Junction in the North Philadelphia neighborhood of Kensington. The wreck killed 79 people and injured an additional 117.
For railroad workers and train engineers, the “Frankford wreck” is legendary. “We all know about the accident in the '40s there,” one engineer told The Philadelphia Inquirer.
Which makes last Tuesday’s derailment at virtually the same spot, now often called the Frankford curve, all the more surprising — both because of the seemingly hard-to-explain high speed at which the wrecked train was traveling and because systems that might have slowed the train to a safer speed were not installed or not operational.
Today’s announcement by the Federal Railroad Administration that — with the reopening of northeast corridor rail lines between D.C. and New York — the technology known as automatic train control has now been installed on northbound tracks at Frankford curve raises almost as many questions as there are brand new speed limit signs on that stretch of historically dangerous track.
First, automatic train control is not the same thing as positive train control (PTC), the federally mandated safety system that has been much in the news since last week’s fatal derailment. As described by railway experts, PTC is a preventative system; ATC is a reactive system. ATC, which is decades old, is one part of a set of integrated technologies that make up the newer PTC system, which coordinates sensors on the track, on the train and at posts along rail lines to monitor train speed and location, along with track problems, and intervenes to slow or stop trains before accidents happen.
PTC requires wireless communications to keep all of the components in sync. How best to roll out that part of the system, and why Amtrak might have faced delays in doing so, has been the focus of some debate in the wake of Tuesday’s fatal accident.
ATC measures train speed over portions of track and alerts an engineer by both lights and audible alarms if the train is going too fast. If the train does not slow in a matter of seconds, ATC will automatically stop the train.
On the Frankford curve, ATC was installed on southbound tracks long prior to last week’s accident, but it was not installed on the northbound side. The derailment occurred on the northbound tracks when the train, traveling at more than 100 miles per hour, entered a curve with a speed limit of 50 mph. The fact that ATC was not in place on the northbound side reportedly came as a surprise to Amtrak CEO Joseph Boardman.
"I didn't know that particular condition existed until this occurred," said Boardman in an interview last week with the Inquirer. "We probably would have changed it, but we didn't know about it."
Still, Amtrak has been quick to defend the decision not to install ATC on the northbound section near the curve. The assumption was that trains leaving the North Philadelphia station would not have time to accelerate to an unsafe speed in the relatively short distance to the Frankford curve. Official speed limits on that approximately 3-mile stretch range from 60 to 80 mph before entering the curve with the 50 mph limit. But because trains could, according to Boardman, negotiate the curve at 80 mph, track engineers considered ATC unnecessary at that point.
"You can get through it at 80,” said Boardman in the Inquirer interview. “You could make it, though it would have been a rough ride."
For trains heading south, the speed limit before the curve is 110 mph, so having ATC in advance of the lower limit was considered more crucial.
But all of that logic is apparently decades old — incorporated into the track’s safety planning well before new, more powerful locomotives were introduced. The derailed train was pulled by a “Cities Sprinter,” an 8,600 horsepower locomotive that is touted by its manufacturer Siemens for its high rate of acceleration. Pulling seven passenger cars, as train 188 was last Tuesday, it would be able to reach its top speed of 125 mph in about two-and-a-half minutes.
Cities Sprinters started replacing 25- to 35-year-old locomotives on the northeast corridor in February 2014.
But whether Amtrak ever took their new locomotive equipment into account, the reality at the time of Tuesday’s derailment was that as a new, more powerful Cities Sprinter approached the Frankford curve at more than twice the posted speed limit (and more than 25 mph faster than Amtrak’s CEO said a train could “get through”), none of ATC’s lights and alarms went off in the engineer’s compartment and no technology triggered an automated braking of the speeding train.
Multiple calls to Amtrak were not returned at the time of this writing. The latest revelations, meanwhile, add to a host of questions about why technologies that could have prevented the fatal accident were not operational at the time of the derailment.
"The theory was to put it where it would result in an accident if you didn't have it," Boardman said in the same interview. For the unfortunate passengers of train 188, that theory was not based on recent and readily knowable data.