After a New York City-bound commuter train derailed last Sunday in the Bronx, it got David Clarke thinking about death and money. The director of the University of Tennessee’s Center for Transportation Research wondered: what’s a human life worth, in dollars?

It’s a question many following the rail industry are asking this week.

The Poughkeepsie-to-New York City Metro-North incident resulted in four deaths and 63 injuries, not to mention millions of dollars likely to be spent on an ongoing cleanup project, pending lawsuits, and an origin-and-cause investigation. From what’s been reported so far, the incident occurred because the train’s conductor, William Rockefeller Jr., slipped into "highway hypnosis" — a daze familiar to anyone who’s driven for long periods on a boring stretch of road — about two hours and 20 minutes after his 5:00AM shift began. When the train derailed it was traveling 82 miles per hour in a 30 miles-per-hour zone just north of Spuyten Duyvil station.

That in all possibly could’ve been avoided if the Metropolitan Transportation Authority (MTA) had installed technology called positive train control on its rail system. Positive train control — or PTC — typically uses GPS or trackside transponders to monitor and control train speeds and to help ensure that train collisions and derailments don’t happen. If PTC had been installed on MTA trains, there’s no way Rockefeller could’ve powered his train over 50mph beyond the speed limit on a notoriously dangerous curve. Similar situations in the past led to a federal mandate requiring that all passenger and freight railways submit a PTC implementation plan to the Federal Railroad Administration (FRA) by December 15th, 2015. A congressional vote passed that mandate into law in 2008 around the time of a grisly train collision in Chatsworth, California, in which 25 people were killed.

But PTC is expensive. It’s estimated to cost billions and Congress has only appropriated a fraction of the overall cost to help pay for it. That’s what got Clarke thinking about the literal cost of death.

"The fact is, you don’t have a tremendous amount of these incidents occurring," Clarke says. National Transportation Safety Board data shows that there were 32,367 people killed in highway-related tragedies in 2011 compared to 759 killed in rail-related incidents that year. PTC could’ve helped to avoid the Metro-North wreck on Sunday, he admits, "but you have to look at the cost-benefit ratio." There were four people killed, he notes, and high-profile critics have responded that billions must be spent to stop it from happening again. "What’s the value of a human life? Is it a billion dollars? A million dollars? A trillion dollars?"

The 2015 PTC mandate "was a knee-jerk reaction to a tragedy" in Chatsworth, California, Clarke told The Verge in April.

"It sounds crass, but if you have a budget, you need to think if this is going to work, and you need to think about your options," he says. A 2010 Government Accountability Office report concluded PTC would only eliminate about 30 percent of rail fatalities each year. "What if I took the billions allotted for PTC and instead spent that money to build overpasses to separate the most dangerous grade-crossing fatality locations?" he asked, referring to the hundreds of people who are killed at these crossings every year. "Would that have a better safety payoff?"

Charles Banks takes the argument a step further. The president of rail consulting firm R.L. Banks and Associates says PTC’s excessive cost will force rail companies to run fewer trains and thus cause more fatalities to society as a whole. "The effect is that you’re going to put more people into automobiles, which are a hell of a lot more dangerous than trains," he says.

While Clarke and Banks openly question whether the PTC mandate should exist at all, industry groups such as the Association of American Railroads have taken a more pragmatic stance: they’ve set their sights on an extension to the 2015 deadline, allying with Republicans in Congress. In August, Republican US Senator John Thune of South Dakota introduced the "Railroad Safety and Positive Train Control Extension Act," which could push back the deadline to December 2022. The bill is pending review in the US Senate Committee on Commerce, Science, and Transportation.

These charts, from a 2010 GAO report to congressional committees, show causes (left) and rates of rail accidents in the US between 2000 and 2009. (GAO)

Steve Ditmeyer, an adjunct railway management professor at Michigan State University who spent years with the FRA pushing safety improvements, says there’s no reason to eliminate or delay the federal PTC mandate

First of all, he says, PTC was not a "knee-jerk reaction to tragedy," but rather a decades-long process designed to make railways safer. The Rail Safety Improvement Act — which eventually set the 2015 mandate — was introduced to Congress "exactly 500 days before the Chatsworth collision occurred," he says, and was signed into law by President George W. Bush on October 16th, 2008, in the wake of a bipartisan senate vote of 74 to 24.

And despite the rail industry’s contention that the PTC mandate is too expensive to accomplish by 2015, Ditmeyer points out that rail companies BNSF, Amtrak, the Alaska Railroad, and Metrolink — whose locomotive and passenger cars collided violently with a Union Pacific Freight Train in the Chatsworth tragedy — are all likely to have their PTC systems implemented by the deadline. He’s also written at length about how rail companies could generate billions in return on their PTC investment.

"PTC, properly implemented, can virtually eliminate collisions and accidents caused by excess speed on curves and on main lines," he says. "And while it has long been agreed that the investment is not able to be justified on safety benefits alone, it is possible for a railroad to use the continuous real-time information that PTC generates to improve train running times, running-time reliability, asset utilization, and track capacity. It’s the business benefits, then, when added to the safety benefits, that justify this economically."

When looking at PTC from a safety perspective only, he says, there’s no question it should be implemented by 2015 — if not sooner.

"It needs to happen to prevent Spuyten Duyvil New York; to prevent Chatsworth, California; to prevent Graniteville, South Carolina; to prevent Chase, Maryland; and to prevent a whole string of other accidents that are fatal to train crews and passengers and to bystanders — to people in the community."

In the wake of the Spuyten Duyvil crash, MTA will be held under a microscope by federal regulators for the foreseeable future. Just this afternoon, the FRA ordered Metro-North Railroad to add new safeguards and modify its signal system to keep train speeds under control. MTA officials have already expressed doubt that New York's public transportation corporation will be able to implement a PTC program in time for the 2015 deadline. The FRA's new order will add tension to an already tense situation.

"If BNSF, Metrolink, SEPTA, Alaska and others can meet the deadline, why can’t the others?" he asks. "I have no answer for that."