NEW YORK -- After a speeding Metro-North Railroad commuter train barreled into a curve and derailed in New York City on Dec. 1, safety advocates said similar deadly accidents might soon be avoided. Railroads across the country are preparing to deploy high-tech control systems that will let computers automatically slow trains that are moving too fast or headed for a collision.
Yet there is already low-tech equipment, widely available since the Great Depression, that could have prevented the crash, and every Metro-North train already has it.
For many years, the trains have been outfitted with control systems that will sound an alarm if an engineer exceeds a designated speed or blows through a red light, then robotically slam on the brakes if the driver doesn't respond.
Historically, though, the system has been used on Metro-North mainly to keep trains from colliding, not to enforce speed limits on curves, hills or bridges.
That meant that no alarm sounded when engineer William Rockefeller failed to slow as he approached a tight curve in the Bronx. Federal investigators said the train was moving at 82 mph, well above the curve's 30 mph speed limit. Four people died in the wreck. Rockefeller said he became dazed or nodded at the controls, according to federal investigators, his lawyer and a union official.
A week after the derailment, Metro-North adjusted its signaling system so trains approaching the bend too fast will trigger the alarm and automatic braking system.
Similar upgrades are planned over the next few months to enforce speed limits at eight other curves and bridges in Metro-North's 384-mile system.
The relatively quick fix for the deadly section of track raises a question: Why wasn't it done sooner?
The simplest answer seems to be that on most U.S. rail systems, engineers have been seen as capable of handling routine speed adjustments on curves and bridges without mechanical backup.
"We operated trains for 30 years and 11 months without a fatality," said Marjorie Anders, a spokeswoman for the Metropolitan Transportation Authority, which oversees Metro-North operations. She added, though, that since the accident, the agency was rethinking its safety operations from top to bottom. Anders said the MTA hasn't yet calculated the cost of installing the safety equipment.
Accidents involving engineers rounding curves too quickly aren't common, but they can be catastrophic.
Last July, 79 people died in Spain when a passenger train hit a curve at 121 mph. The Spanish rail system had sophisticated automatic braking systems, similar to the new "positive train control" systems being deployed in the U.S., but the equipment hadn't yet been installed on that section of track.
In 2005, a passenger train hit a building in Amagasaki, Japan, when an engineer took a curve too fast. That wreck killed 107 people. The train was also equipped with an automatic braking system, but it hadn't yet been set up to check speeds in the spot where the crash happened.
Speed enforcement systems on U.S. passenger trains vary widely. Generally, systems that do have automatic braking are set up to make sure engineers don't accidentally overtake trains operating in front of them or speed through crossovers where trains shift from one set of rails to another.
On Chicago's Metra system, just a few lines have equipment that will automatically stop a train moving faster than a signal allows. Like Metro-North's system, though, those protections are set up to make sure drivers pay attention to signal lights, not enforce speed limits on open track.
"It is the engineer's job to know his territory and know the proper speeds along his route," said Metra spokesman Michael Gillis.
The Southeastern Pennsylvania Transportation Authority, which provides rail service around Philadelphia, has automatic train control on most of its system but doesn't typically use it to enforce speed limits on curves.
Amtrak said it has automatic braking technology on the sharpest curves in its busy Northeast Corridor between Washington, D.C., and Boston.
The Long Island Rail Road, which is also overseen by the MTA, has a system that automatically enforces track speed limits at nine locations, in addition to its more routine job of maintaining space between trains.
Some passenger rail lines lack automatic brakes entirely, even to enforce stop signals.
There was no automatic braking in place on a Metrolink train that ran a red light and struck a freight train in Chatsworth, Calif., in 2008.
That crash, which killed 25 people, prompted Congress to order big rail systems to install positive train control. Those systems monitor the location of every moving train and provide automatic, emergency breaking anywhere.
Many railroads have indicated they expect to have trouble meeting the 2015 installation deadline. Some railways have reported difficulties acquiring technical components or radio bandwidth required to operate the system. The MTA plans to spend $900 million to fully quip Metro-North and the LIRR.
Railroads also have until 2017 to install alarms designed to keep engineers awake. Right now, some trains have those alerts. Others don't. Rockefeller's train had one but not in the control compartment he used the morning of the crash.
Robert Paaswell, a civil engineering professor at the City College of New York and former director of the University Transportation Research Center, said he didn't think Metro-North's failure to expand its existing automatic braking system earlier was negligent.
"The history along that curve was that for many, many decades and thousands of runs, nothing had happened," he said. "This poor unfortunate guy had the tragedy of his life."
Positive train control should help prevent future speed-related crashes, said Ross Capon, president of the National Association of Railroad Passengers. But he said railways shouldn't delay making temporary improvements.