Would More Technology Mean Safer Trains? In 2008, Congress passed a law requiring most rail networks to install "positive train control" collision technology by 2015. Engineering professor Christopher Barkan discusses train safety systems, how "positive train control" might prevent accidents, and whether railroads will be able to meet the deadline.

Would More Technology Mean Safer Trains?

Would More Technology Mean Safer Trains?

Audio will be available later today.

In 2008, Congress passed a law requiring most rail networks to install "positive train control" collision technology by 2015. Engineering professor Christopher Barkan discusses train safety systems, how "positive train control" might prevent accidents, and whether railroads will be able to meet the deadline.


This is SCIENCE FRIDAY, I'm Ira Flatow. For less than $100, you can buy a little gadget, a speedometer, that plugs into your car's cigarette lighter and it will let out a terrific scream when you exceed that speed limit that you preset into it. In fact, there's a 99-cent app for that too for your smartphone that tells you when you've exceeded the speed limit.

If such a simple device had been installed on the commuter train that derailed last Sunday, killing four people in New York, perhaps that accident might never had happened. The trainman who was driving the train, the engineer, was never warned by any device on that train that he had greatly exceeded the speed limit on a winding curve.

Why not? There is no automatic braking system related to exceeding speed limits that would slow the train down automatically either. None like the kind you can get in many cars on the road today. Why not? Do we have enough safety technology on our trains? Would something called positive train control technology have prevented these accidents?

According to, you know - and why isn't it already in place on Metro North commuter trains? Why not install some simple off-the-shelf device that would keep the track - keep track of train speeds and alert the engineer driving the train, like that simple app or a little gadget? What do you think? Our number, 1-800-989-8255 is our number.

Christopher Barkan is a professor in the department of civil and environmental engineering, executive director of the Rail Transportation and Engineering Center at the University of Illinois at Urbana-Champaign. He joins us from Urbana, Illinois. Welcome to SCIENCE FRIDAY.

CHRISTOPHER BARKAN: Hello, Ira. It's a pleasure to be here.

FLATOW: Now, that Metro North train was going 82 miles an hour, 82, before the accident and the engineer pulled the brakes six seconds before the train crashed and it was going way too fast for that curve. Why did he not know that he was going too fast for that curve and why wasn't the train able to detect that in this modern age that we have of electronics?

BARKAN: Well, there certain is technology that would allow both the train and the operator to know what the speed is, and I, you know, couldn't possible comment on what was happening in the cab of that locomotive today. I mean I - that day. But the simple fact is, that particular train, as I understand it, was not equipped with technology to perform the function that you just referred to.

FLATOW: Let's talk about a little bit of the technology and the terminology that is being talked about here. The engineer said he dumped the brakes. What does that mean exactly?

BARKAN: Yeah, that's kind of a colloquial term that's widely used in the railroad industry when you put the train into emergency, and what that means is that there are - every car on a train is - well, let me step back a moment. The energy to apply the brakes in a train comes from compressed air that is provided by an air compressor in the locomotive.

And so, and each car has a tank, a reservoir, as we call them, in which that compressed air is stored. And in fact, each of those reservoirs has two compartments. One is what we call the auxiliary compartment, and the other is the emergency compartment, and it is that compressed air that provides the force against a cylinder that then is applied to the brake shoes that then are applied to the wheels themselves to decelerate or stop the train.

And the braking system works. It actually was invented by George Westinghouse in the 19th century and the basic concept is still the same, where you compress the air in all of these cylinders or reservoirs in the train and then when you release - when you reduce the air pressure in the train line, the air pipe that connects all the cars in the train with the locomotive, that causes varying amounts of air pressure to be released from the reservoir and applied to the brake cylinder to apply pressure against the brake shoes against the wheels.

And when you dump it, you're basically opening up that - you're turning a valve in the locomotive cab that causes all the air in that train line to be released and that causes all the compressed air pressure in those reservoirs on each of the cars and the locomotive to be applied quite rapidly against the wheels in the train, and therefore stopping it as quickly as possible.

FLATOW: In this day and age of apps and automation of cars - cars can park themselves, drive themselves, they can now detect when there's an imminent crash happening and apply the brakes, they know when they're going off the road - could we not take some of the simple technology, put it on a train and say, you know, if the train is going too fast, it has GPS on the train? Shouldn't it be that hard?

I mean, I think some high school kids could figure this out.

BARKAN: I would like to meet those high school kids.

FLATOW: They've been on our show. I mean it doesn't seem to be that difficult to figure out that there's a curve up ahead, slow the train down.

BARKAN: Well, I would point out that that railroad, as we've learned in the media, these are the first four fatalities in 30 years of operation of Metro North.

FLATOW: I ride this railroad almost every day and I've heard those whistles going off in the engineering cab and have asked the conductor what's going on, over the years, and he said they've exceeded the speed limit and he's getting a little notice of that.

BARKAN: Right. So that equipment is - many of the cab cars are equipped with what's called an alerter. There's several different kinds of technology we're talking about, and the one that you're referring to is the so-called alerter, and I think it's equipment built after 2000 by federal regulation. All equipment must be equipped with the alerter that you're referring to.

Earlier equipment also has to have it unless, and this is the sort of irony of this situation, equipment, according to federal regulation, equipment built earlier than that does not have to have an alerter if it has a cab signal system.

FLATOW: I understand. What I'm asking, and I don't mean to interrupt, what I'm asking is how hard would it - I can look on my cell phone on the map on my iMap or whatever; it has a GPS system, it shows me the railroad track as I'm going around it. Why can't I build a simple little app into an iPhone or any other smartphone that says, hey, there's a curve coming up, put the brakes on if you don't do it.

BARKAN: Let's extend your analogy. Would you put your life on the line, depending upon the proper functionality of your cell phone under every circumstance you possibly ever travel in? And I hope your answer is no.

FLATOW: Well, people put their lives on the line for, you know, this train and didn't survive on it.

BARKAN: Well yes, but...

FLATOW: There are many trains that don't have people that run them. A lot of them, people go to airports, go in these trams all the time.

BARKAN: Yeah. Well, let me again make the point, that in 30 years of Metro North operation, the systems that they've had in place have provided safe transportation to, you know, not millions but I think over a billion people in terms of rides.

FLATOW: And I'm not arguing against that. I'm agreeing with you. I'm just saying how difficult would it be to back up a system of the people who are on the train with a simple little device that knows the train's going too fast around a curve? I can get a few high school students to write an app, I think, for that.

BARKAN: Well, you know, if you'd like to understand the difficulty of this technology - why don't we make one other point that referred to something you spoke about earlier. You can develop these applications and they work very well for one person using one phone or one automobile, but you have to build this system so that it is extremely robust. It is completely basically what we call failsafe. It cannot fail and that means that requires a lot of extra elements of redundancy and very careful, complicated technical design to be built into the system.

BARKAN: And furthermore, they're not operating in isolation. Every one of these systems has to operate in conjunction with other infrastructure and other equipment and what we call the back-office server, the thing that's actually controlling the whole railroad. This is a non-trivial technical undertaking and I'm not alone in considering it that way.

I think if you were to speak to officials in the Federal Railroad Administration, the leaders of technology in both the U.S. railroads as well as overseas railroads, as well as the Railroad Supply Institute, the people who have been building and developing these kinds of technologies for decades, you would find that they would agree that this is not as simple a problem as (technical difficulties) talking about apps on phones and technology that you can apply to an automobile.

FLATOW: Okay. I guess I'm being naive. I would think that, you know, if an engineer or the conductor can't notice that a train is going 80 miles an hour into a 30-mile curve, that a device could not back that person up and say uh-oh, you're going too fast into the curve. You ought to do something.

BARKAN: Okay. Nobody is - we're confusing two different things here.

FLATOW: I'm not, I don't think.

BARKAN: Well, I think you are, actually. There's certainly technology available - let's talk about several different elements of what the train control system and the alerter system are supposed to do. The alerter is basically to do exactly what the name would imply. It's basically to ensure that the locomotive engineer is, you know, paying attention, sort of properly engaged, is doing things that show evidence to the technology that he or she is, you know, paying attention to what needs to be done.

That's entirely separate from the traffic control system or the train control system. What Metro-North has in place is actually arguably one of the more sophisticated systems in United States right now which is automatic train control, including cab signals. So he or she will see on their console the status of the track several miles ahead, what we call blocks of traffic control blocks, and that will give him information as to whether he needs to slow down or stop the train in response to upcoming trains or other elements of the infrastructure such as switches that are thrown one way or the other.

What it will not do is it will not take into account what we call civil infrastructure constraints like a curve such as at Spuyten Duyvil. And it's not that there's not technology that could do it. It's that that technology is not installed on that train. And again, this is the point I've been trying to make. In that situation we rely on human beings, you know, the careful attention of the locomotive engineer to do their job properly.

And what, again, the point I'm trying to make, or was trying to make, is that in 30 years of operation of Metro-North, they have managed to be able to rely on their train engineers to properly obey the rules and operate in a satisfactory manner so that such a thing does not happen. But as we all...

FLATOW: Let me go to the break. I'll come back. Take a break, I'll let you finish your thought when we get back. So stay with us. We'll talk more with Christopher Barkan after this break. Don't go away.

I'm Ira Flatow. This is SCIENCE FRIDAY from NPR.


FLATOW: This is SCIENCE FRIDAY. I'm Ira Flatow. We're talking with Christopher Barkan, professor in the department of civil and environmental engineering, executive director of the Rail Transportation and Engineering Center at the University of Illinois at Urbana-Champaign in Urbana, Illinois, and he's trying to tell me how difficult a problem it is to get these trains to - well, how would you describe it?

BARKAN: Well, again, what I've been trying to say is that we have technologies to do these things. Some of them have been around for many decades; other ones are still in the process of development and implementation. And it's not as though it's impossible to perform the functions that you were alluding to earlier on. It's that in this particular case, the train was not equipped with the technology that you're - now, that's easy to criticize, you know, after the fact, but the fact is, is that North American railroads have an extremely safe record of operation, one of the safest in the world, in fact.

And so you can always spend more money on more technology and make it safer, but the question is, is that necessarily the most rational investment of your resources. And we do have other safety issues that we need to invest in as well, so...

FLATOW: Would you agree that there are going to be hundreds of millions of dollars of lawsuits here, that if you had sunk into the railroad years ago, this might not have happened? You're going to wind up paying one way or the other.

BARKAN: Well, I couldn't comment on that. I'm not an attorney. I really am not privileged to those sort of things, but I agree that there probably will be litigation, but I don't know.

FLATOW: All right. We'll find out and see what happens. I didn't mean to beat you over the head with this. I really didn't. It just seems like sometimes there are simpler answers to complex problems than they appear to be.

BARKAN: Well, but I would argue the opposite. This case is actually a very complicated problem to solve in that general sense. Now, you're right. You can come in after the fact and say that Metro-North should have done this, that or the other thing, and I'm, you know - but that's kind of a post-hoc thing. A week ago we wouldn't have been having this conversation; a week ago they had 30-year record of operating safely without any fatalities and, you know, you wouldn't have been interested in talking to me about this question.

FLATOW: All right. Thank you very much for putting up with me. Christopher Barkan, professor in the department of civil and environmental engineering, executive director of the Rail Transportation Engineering Center at the University of Illinois at Urbana-Champaign in Urbana.

Copyright © 2013 NPR. All rights reserved. Visit our website terms of use and permissions pages at www.npr.org for further information.

NPR transcripts are created on a rush deadline by an NPR contractor. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.