December 2, 2013

Thought of Train

The terrible train accident yesterday took place only about ten minutes by bus away from my church. It is a train line I take quite often when heading north. Waking to the news, I was struck at how much the Gospel of the day echoed the suddenness and peril of life: "Two are in the field, one is taken and another left... two are at the mill, one is taken and the other left..." Two are in a railway carriage, one is taken and another left.

I was relieved to hear later in the afternoon that my brother in Christ William Francis wasn't on the train, having made the uncharacteristic choice to miss the solemn liturgy at SMV. Again, as the Bard observed, there's a destiny shapes our ends... Or, as it is written in the annals of Dune, When it is time for one to die, there arises in that one a longing to go to the place of its death. It was not WF's time, and for that I give thanks, even while mourning the deaths and injuries of those whose time had come.

I was surprised, even later yesterday, to see on the news the more detailed reports that the train was being pushed, with the locomotive at the north end. That seems to be a recipe for disaster, as any problem with the southernmost carriage will cause a pile up -- which appears to be exactly what happened at that curve in the track. I've been around trains all my life, and I know this pushing mode is used from time to time, sometimes as an assist. But to run an entire trip from Poughkeepsie to Manhattan in this mode seems to me not to be a good practice.

Let us hope that the evidence shows the cause of the tragic accident, and provides recommendations to avoid any more on this heavily traveled corridor.

Tobias Stanislas Haller BSG


Christian Paolino said...

I have taken Amtrak's Vermonter service which has a diesel locomotive on one end and an electric on the other. The electric engine pulls the train as far as the catenary lasts, then the train reverses direction and the diesel takes over.

I never thought about it, but I guess that on the return trip, which operates the same way, the active locomotive is pushing, not pulling, unless they uncouple the engines at the top of the line (White River Junction) and reverse their positions.

Tobias Haller said...

Christian, I'm familiar with the need for a switchover from electric to diesel -- but never having observed it from "outside" I'd always assumed the engine was put on at the leading edge, whichever way the train was moving. I'm also familiar from early travels in the hills of Western Maryland on the B&O that sometimes multiple engines are needed for the steeper grades.

I can only hope they soon discover the source of this particular accident.

IT said...

I'm a daily rail commuter on Amtrak's Pacific Surfliner, where the push-pull is routine. (The locomotive pushes into LA, and pulls when it leaves LA). This allows trains to be used more efficiently. Since trains live in a 1-dimensional world, you can't easily reverse the orientation. Even if there is a railway wye nearby, it is a lengthy effort. using push-pull, they can immediately turn the train. For a station like LA-Union, which is a stub (dead end), that's important.

The photos suggest that the locomotive in the NY crash was a "Genny", which on Amtrak is used for long distance service. It packs a punch, unlike the F59 commuter locomotives on my Pacific Surfliner, which are lower power.

After the 2005 Glendale crash on the Metrolink (a commuter rail service in Southern California), that service "hardened" the cab cars.

You are correct of course that the physics mean that the momentum can keep the loco pushing. In this case the engineer had dumped the brakes, so it was momentum, not propulsion. The problem here is clearly too much speed coming into that curve.

Eliminating push-pull is just not going to happen.

Tobias Haller said...

Thanks, IT, for the greater detail. And as with the line in CA, the MTA "dead ends" in Manhattan, meaning it would require a good deal of sidetracking to move engines back and forth.

Still, where the push model is used, caution is all the more vital on curves, precisely due to the physics (ever tried to "push" a chain?).

Brother David said...

The news we hear in Dallas is that the train is going about 70 mph before the curve and must slow to 30 mph to make the curve. The engineer is saying he applied the brakes and they failed. Hopefully the black box will tell if that is true or not. If the brakes indeed failed, then they will need to determine why.

khugrok said...

Was this one of the new locomotives? They're handsome and zip right along. I was surprised by the speed of through trains when we were waiting after a visit to NYBG last summer.
Concerning the Vermonter: Christian snoozed through the change of engines in New Haven. Further north, there's a huge diesel locomotive on each end. The one in front is used in either direction. Given the state of that RR, it's a good thing to be able to put the driver in front if you have to reverse.

Tobias Haller said...

Thanks, David, and Khugrok. I don't know what model the loco was. I assume full details will be forthcoming.

I also find myself wondering, and my parish treasurer asked me today, how can the engineer see is there might be an obstacle on the track if in the last "car" (the engine) - particularly on that curve! Given all the concerns about terrorism, one wonders how this is addressed?

IT said...

I think there is some confusion.

Trains that run on a push-pull system have a modified "cab" car in the front of the train when the locomotive is in the push mode. The cab car has a compartment for the engineer, who sits there and drives the locomotive at the end remotely. Thus, there is no one in the engine. This is routine on trains; if you think of those big freights that are pulled by multiple engines, only the lead engine is actually staffed, and the others are controlled remotely.

It looks from the pictures like the engine was a GE Genesis, known as a Gennie. They are powerful locomotives that Amtrak uses for long distance routes. As I mentioned above, my commuter Amtrak in CA runs on F59 locomotives, which are less powerful. Commuter cars are lighter than the big cross-country cars, so they don't need that much horsepower, and the F59 speeds up and slows down quite quickly. Occasionally they hook up a Gennie to the consist (= train set), and sometimes the driver slightly overshoots one of the stations, because the Gennies are not as quick to slow down. (They are built to lope efficiently at speed). Don't know if that had something to do with the current sad event.

The emergency brakes on a train work by air pressure; if you pull an emergency handle (or if the engineer "dumps" the brakes), that means that the air is released from the system and the brakes deploy.

I find it more disturbing that one of the reports said that the throttle was not released until just seconds before the event. I wonder if there was a throttle malfunction?

Tobias Haller said...

Thanks so much IT for the info. It did strike me aas a bit wacky that the engineer would be running blind! Still, I find it hard to picture sitting seven carriages ahead, knowing the mometum of that engine... even if the brakes work... pushing from behind as the rest of the train accordians behind you! Which is more or less what the ariel view shows.

Something clearly went very wrong here. I hope it can be identified and remedied.

IT said...

This morning's news suggests that the engineer may have dozed off. He must have maintained an iron grip on the throttle if so, since most trains use a "dead man's hand" system that requires positive force to keep the train moving. A tragedy all around.

Brother David said...

Sadly, so many recent train wrecks have been ultimately attributed to driver error amounting to dereliction of their obligation of care. The engineer in Spain ran away from the accident because he knew that he was guilty. The MetroLink headon collision in So Cal a few years ago was attributed to the driver; excessive speed and texting while driving, a distraction that ultimately caused enough inattention that the train ran a red light.

I think that these are examples of folks becoming either so bored with the routine of their job or so self-assured of their own competency, that they drop their standards. But standards and attention are so important in so many jobs where more than just your own life depends on your expertice and reliability.

Tobias Haller said...

Thanks, IT, and David. Human error is so much a part of our own lives; how tragic when it affects the lives of so many others, even in less dramatic ways than this.

I recall the "dead man's throttle" principle from The Taking of Pelham 1-2-3 (the original version). If the engineer dozed, he must have developed a Charles Atlas grip...