Acela & Amtrak NEC (HSR BOS-NYP-WAS and branches only)

Arlington said:
WSJ is reporting:

Sure, this is going to call for Congress fully funding PTC, but what we really need is Congress fully funding curve-straightening. This stretch of ROW, or the whole stretch from a "Market East" station is what really needs to be implemented.
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NBC news is saying it was going over 100mph which seems absurd.
 
I know that in the plans for NEC's future, Amtrak is to serve Market East (now called Jefferson) instead of 30th Street Station. It seems the proposed route would deviate from the existing right-of-way near where this derailment occurred. Does anybody know the exact plans of how Amtrak was proposing to access Market East/Jefferson?
 
Jahvon09 said:
Speed might be the deciding factor, as the train was entering a sharp curve just before the accident. It was supposed to be a lower speed zone at that point than the normal speed at which the train operates. There are STILL scores of passengers unaccounted for!
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Frankford Jct., this exact spot, was site of one of the deadliest passenger train accidents in U.S. history back in 1943. It's a nasty curve, 30 MPH speed limit. Since it's only a couple miles north of 30th St. station and has to pass through several other junctions where all the SEPTA Regional Rail and freight lines converge/diverge, speeds only vary from 30-60 MPH north of 30th St. until they clear this junction.

One of the other sad things about it is that it was one of the NEW locos involved in the crash, so we know that it was not the engine that failed.
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Actually, we don't know anything yet to say whether it was the train, the track, the locomotive, or the coaches that started the chain reaction. The Sprinter was relatively undamaged save for a busted headlight and some damage underneath from tearing out the rail on 2 tracks before skidding to a rest. It's repairable.

If the loco wasn't at fault it may have been fortunate that it was a Sprinter leading the train. They have black box recorders and hazard cameras, with Amtrak able to download the feed wirelessly and monitor it live as the train is moving. The AEM-7's don't have that kind of security tech, so the Sprinter's flash memory may be the only live eye looking at the tracks as it happened.

Arlington said:
Curve, speed, cracked rail (rapid change in temp), and new-locomotive bug are all still in play as causes. I think direct freight collision is the only thing ruled out.
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Yes. That was erroneously reported early on because the locomotive skidded so far that it landed near a string of tanker cars in the freight yard. But the train wasn't anywhere near those cars.

This is the aerial view: https://goo.gl/maps/KlyWq. The 4 tracks at top are the NEC. That derelict footbridge thing and the warehouses at top are in all of the news photos. The coaches all tipped over to the left of the footbridge and top of the photo, while the locomotive skidded from 2nd track from bottom, crossed to the right of the footbridge, and came to rest near the front of the line of tankers. Unbelievable amount of lateral movement.

Zoom out and you can see how the junction works. The line that diverges straight to the east bridging over the freight yard is the NJ Transit Atlantic City Line. That goes straight while the NEC takes its sharp turn north. The freight yard is part of a series of small spurs looping all around the neighborhood. From what they said somewhere on the RR.net thread, these are not Hazmat tankers.

cden4 said:
I recall reading after the derailment last year that the Amtrak trains don't have automated speed control and they don't have the money to install it. After this latest incident, I wonder if that will change. (Assuming speed was the reason for this crash as well...)
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The ACSES PTC system--same one that's been in use New Haven-Boston since 2001--is installed here on this portion of the NEC. However, it's not been turned on yet because they're still debugging the radio interference. All of the hardware's installed, all of it's been tested. But it can't go live until they stamp out the last interference spots...one...by...one. And find out what time of day it's being interfered with. Needle in haystack.

The stupidity of Congress laying down that mandate with no material support for the implementation is that you have these kinds of holdups: they so blithely assumed the 'magic!' of wireless technology would make this all a piece of cake that they forgot to think about spectrum acquisition. So even a relatively battle-tested, non-GPS system like ACSES ends up having trouble with radio interference when it's right smack downtown in the most densely-packed metropolises of the most densely-packed megalopolis in the country. Oops.


Still, there is speed enforcement here in the form of vanilla cab signals. So it's not all that easy to overspeed. The signal system sends the speed limit code at each signal block, the signal readout in the engineer's cab reads the code, and if the train is over the speed limit a penalty gets applied. Usually on a sharp curve like this the signal layout will pump out that restricted speed code several times over in a short span to stay airtight so Larry Leadfoot can't game the system. With the Metro North Spuytien Duyvil crash the signal layout was the problem: the curve was restricted and enforced by the signals like it was supposed to... but Metro North left too big a gap between signals so the dozing engineer had running room to re-speed up after clearing the first restricting signal. PTC would've helped by keeping the speed enforcement constant instead of intermittent, but it wasn't necessary to have PTC to prevent that accident. Metro North should've seen long ago--like, decades ago--that they had a gaping hole in the cab signal layout smack in the middle of that curve that needed to be plugged...and that's what the NTSB threw the book at them for.

I would hope Amtrak wasn't as careless here. It would seem inconceivable that they were given Frankford Jct.'s long history of deadly crashes, but you never know. That's what we have an NTSB for.
 
There's some speculation online that it was going over twice the allowed speed through the curve.

Somewhat similar to this 1990 crash here.
 
Matthew said:
There's some speculation online that it was going over twice the allowed speed through the curve.

Somewhat similar to this 1990 crash here.
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Yup. Similar deal as the Metro North crash. Operator error meets a speed enforcement gap in the cab signals. SW Corridor does have PTC with constant speed enforcement so the type of overspeeding that caused that crash has been impossible for 14 years now. But...it would've been for all practically impossible with the extra cab signal warning Amtrak installed on the curve in '92. They got the book thrown at them by the NTSB for not having that just like Metro North did.

SW Corridor was only open for 3 years at the time of that crash so it was still a new-new-new ROW where the highest-risk spots may not have been fully teased out. Sometimes you just can't know well enough to stamp out every such signal gap preemptively. Metro North, however, didn't have that cover for Spuytien Duyvil, which is 100+ years old and has had many derailments of varying severity and cause in that century. Just like the infamy of Frankford Jct. wouldn't give Amtrak that cover if (and we're a long ways from knowing if) similar over-speeding was a factor.

At least with PTC those overspeeding risk spots do get plugged airtight. But, of course...the @#$% system has to be online first. And there is no place in the country harder to stamp out the spectrum interference than New York City, Philly, and D.C.
 
5 PM NTSB presser:
Train was traveling at 106 mph when the brakes were activated, over a period of 3 seconds, slowing the train down only to ~102 before it derailed.

"Had [PTC] been installed, this accident would not have occurred" -- direct quote
 
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datadyne007 said:
5 PM NTSB presser:
Train was traveling at 106 mph when the brakes were activated, over a period of 3 seconds, slowing the train down only to ~102 before it derailed.

"Had [PTC] been installed, this accident would not have occurred" -- direct quote
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Ayup. Looking like a repeat of the Metro North crash at even more extreme a speed. Although no doubt the fine print of the report will also say:

". . .and so would a better-spaced cab signal cut".

In other words. . .

1. The signals were spaced on the assumption that the max Larry Leadfoot could've possibly been going approaching Frankford Jct. was X MPH (70, 80, whatever). And thus the speed enforcement code would've dinged the train and applied the brakes with enough running room to slow to safe operating speed by the time it hit the curve. i.e. Its human designers spaced the restricting signals based on an assumed upper-bound speed and the basic physics of slowing that assumed upper-bound speed to safe speed.

2. The signal placement did NOT account for Larry Leadfoot somehow going X + Y = 106 MPH when the speed code triggered the braking, therefore the train had nowhere near enough running room to slow from 106 MPH to safe speed by the time it reached the curve. And in fact blew the speed limit by such a huge margin that the penalty application of the brakes was only able to shave 4 MPH off before it jumped the tracks. So the upper-bound speed the human designers of the signal spacing assumed was the max head of steam anyone could be going before they got dinged...severely underestimated that max speed. Maybe their estimate only covered 99.99996% of the possible range of max speeds instead of 99.99998% of the range of max speeds. And this train was in the .00002% difference said human designers didn't account for.

And that's the difference between life and death.


In a nutshell, that was more or less the NTSB's conclusion with both the 2013 Metro North crash and the 1990 Back Bay crash.

The cab signal system did its job. It's been doing its job for 93 years on the NEC. Simple, effective, nearly bulletproof, and not in the least bit obsolete. Probably has prevented thousands of potential accidents in this very spot. It detected a train traveling greater than authorized speed and applied the penalty. But it didn't account for how in the hell this train got up to 106 MPH, because that's not its job...that's the several signals before this one's jobs to apply the lighter...then increasingly heavier...restrictions before the train ever got this far this fast.

If the signals between 30th St. Station and here are proven to be in fine working order, then the only way the train got moving that fast in the first place was because of a loophole where the earlier signals were allowing much too permissive a speed coming into this signal. A blind spot...not in the actual signals themselves, but in the humans that installed that signal layout. Meaning the humans who installed that signal layout had a blind spot about the human behavior in the engineer's seat. And had the humans not had a blind spot, neither would the signals here.


PTC closes the last loophole by making the enforcement continuous so it's not even possible for an engineer who forgets the speed limits to exceed the speed limit in the first place. Or the signal designers to leave a loophole in their signal layout. "Positive" = proactive. It's proactive about stamping out human error. Cab signals are fundamentally reactive (though PTC doesn't replace the cab signals, it complements them...there's still a lot of 'reactive' tasks still to do).

But it's inaccurate to say no PTC = literal difference between this accident happening and not happening. If the humans hadn't left a blind spot allowing the train to rev up that fast before the first restricting signal...cab signals would've prevented it. Humans failed the technology, the technology didn't fail the humans.

What Amtrak's going to have to answer for is how this loophole ever managed to persist for as long as it did at this very spot. Metro North not getting wise about its loophole at Spuytien Duyvil was bad enough. There's thousands of trains per week passing through this part of Philly.
 
^ It is being reported that the "engineer applied the emergency brake" moments before it derailed. It sounds like a manual activation, when you're describing something that sounds automated in regard to the brake being activated.
 
datadyne007 said:
^ It is being reported that the "engineer applied the emergency brake" moments before it derailed. It sounds like a manual activation, when you're describing something that sounds automated in regard to the brake being activated.
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The way it works is:

1. The signal system 'fires' electromagnetic pulses at a certain Hz frequency through one of the running rails (occasionally switching sides to the other rail every so often at an insulating joint). Even idle like this it can tell which switches are thrown and whether there's a break in the rail just by where that pulse travels between insulators.
2. The train's axle passing over this pulse completes the 'circuit' by passing it through the other running rail.
3. Signal system detects the completed circuit on the return end.
4. By detecting the completed circuit the signal system can ascertain the position of the train to within whatever area the circuit is in (i.e. between insulating joints). And in some cases crudely estimate the speed based on how many insulated circuit sections it passes over in a given time.
5. The signal system can 'fire' a change in signal based on position of the train, such as signifying that the next block is occupied or telling the train to slow down. Basically, every single function the signal system performs is based on where those circuits do and do not complete themselves.

^^Even non- cab signal lines with just the wayside lights have track circuits (most of them...the T still has a couple truly ancient installations like Rockport and Reading that don't have circuits at all and just switch the lights through pole-mounted telephone wires by side of the track). On a wayside-only system the track circuits only control the signal lights, not the train.



The cab signals are an extra layer on top of the track circuits. The existing track circuits fires the pulses, and the train has an antenna mounted on its underside by the wheels that detects those pulses (all while its wheels are making the 'circuit'). The engineer's controls have a readout that interprets those pulse patterns as "codes". The codes convey the same exact information that the patterns of wayside signal lights do: basically "clear" (full speed ahead), "restricting", and a couple of intermediate categories. The engineer is still controlling the train, and still has to know the speed limits on a given stretch of track. But when the code gets changed to something more restrictive, a buzzer sounds and they have so many seconds to get in compliance with the speed limit before a brake penalty is applied.

If the X seconds of warning expire with no engineer action applying the brake to slow down to the new speedlimit...the signal system steps up the penalty by cutting out. "Cutting out" means what it implies: the signal shuts off entirely, and no longer makes a circuit. Train loses the signal...it goes into emergency. Loud alarm goes off at the console, and if you do not hit those brakes in a split second the train forcefully does it by itself and a bunch of passengers get a rough jolt and start swearing at your conductor co-workers...who then chew you out. Old Colony, Stoughton, Fairmount, Worcester commuters: you've probably been on trains that have done the rough WTF? slowdowns when the engineer gets slapped by the cab signals.


That's the fail-safe. The train treats it as if there's a problem with the signals and that they've gone totally offline. So you stop, and you can't proceed at >20 MPH until the train picks up a new signal telling it that it can do something else. The simplicity and robustness of the system is that the "Engineer bad!" punishment is the same as the "Hold up! I think we might have a track problem ahead; I can't see the signals!" alert like a broken rail.


The type of PTC system ("A.C.S.E.S.") that Amtrak is installing here--and which has had running New Haven-Boston since '01--is a third layer on top of the track circuits and cab signals. Both of the pre-existing layers still perform all their vital functions, but the RF transponders allow for full 2-way computer communication with the trains to fine-tune things much more precisely and close the last loopholes. The old tech is near-perfect at what it does best, so this flavor of PTC is strictly an augmentation that adds new safety features. If the PTC computers go on the fritz, then you still have the full force of the cab signals backing everything up.


-----------------------------


When they use the term "train went into emergency" in these news reports...that means the engineer blew the signal, did not respond in time, got slapped with an "Engineer bad!" drop-out, did not respond NOW, then the train went into automatic stop. But 106 MPH was way way too fast for the braking maneuver to slow the train enough before it jumped the tracks. 3 seconds, -4 MPH, and then Amtrak's data feed to the locomotive's black box cut out...presumably that was the start of the derailment. The shudder that the was felt throughout the cars before they went flying was probably that emergency braking hitting the start of the curve and tearing out the rail.


You can probably do some complicated maths based on the position of the signal that sent the last penalty and the stopping distance to figure out what kind of upper-bound speed that signal's placement was designed to stop in a worst-case scenario. It certainly was designed for a hell of a lot less an upper bound than 100 MPH...Physics 101 will tell ya that much.

So the question is...how in the hell did this train accelerate to 106 MPH so quickly to elude the previous signal from applying the harshest braking penalty? Because the previous interlocking by North Philadelphia station imposes a 60 MPH limit for a short distance that would've involved a hard penalty. And we know this train wasn't running flagrantly afoul back there. Then in the short distance of 70 MPH territory after N. Philly station but before Frankford Jct. there's 1-2 more intermediate signals that would've started tightening the noose before this last one cut out. You're talking, like, 20-30 MPH acceleration in a third- to half- mile to elude the signals if they were functioning. All while pulling 8 coaches roughly 40% full. If a Sprinter locomotive has ever achieved that kind of acceleration before, it was probably on a Siemens test track. Somehow, some way, this engineer managed to pull that feat off on an exceptionally curvy stretch of the NEC.



Yeah. I can see why that guy's lawyering up to his eyeballs right about now. I mean...wow. We're so cosmically beyond [*puts on Desi Arnaz voice*] "You've got some 'splaining to do" here.
 
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Matthew said:
There's some speculation online that it was going over twice the allowed speed through the curve.

Somewhat similar to this 1990 crash here.
Click to expand...


Yeah, that has been officially confirmed. That the driver had waited until the very last minute to try to slow the train down, and once in the curve, the train only slightly slowed down - from 106mph to 102mph.

The death toll went up to 7. Also now, the news report says that the driver supposedly doesn't remember anything. Yeah, right!

it is also suspected that the train was late leaving Washington, and that the drive was trying to make up for lost time by pushing the train to go faster!

A little boy whose dad was on the train is asking for help in locating him. He was in the first car. :eek:
 
F-Line to Dudley said:
The way it works is:

1. The signal system 'fires' electromagnetic pulses at a certain Hz frequency through one of the running rails (occasionally switching sides to the other rail every so often at an insulating joint). Even idle like this it can tell which switches are thrown and whether there's a break in the rail just by where that pulse travels between insulators.
2. The train's axle passing over this pulse completes the 'circuit' by passing it through the other running rail.
3. Signal system detects the completed circuit on the return end.
4. By detecting the completed circuit the signal system can ascertain the position of the train to within whatever area the circuit is in (i.e. between insulating joints). And in some cases crudely estimate the speed based on how many insulated circuit sections it passes over in a given time.
5. The signal system can 'fire' a change in signal based on position of the train, such as signifying that the next block is occupied or telling the train to slow down. Basically, every single function the signal system performs is based on where those circuits do and do not complete themselves.

^^Even non- cab signal lines with just the wayside lights have track circuits (most of them...the T still has a couple truly ancient installations like Rockport and Reading that don't have circuits at all and just switch the lights through pole-mounted telephone wires by side of the track). On a wayside-only system the track circuits only control the signal lights, not the train.



The cab signals are an extra layer on top of the track circuits. The existing track circuits fires the pulses, and the train has an antenna mounted on its underside by the wheels that detects those pulses (all while its wheels are making the 'circuit'). The engineer's controls have a readout that interprets those pulse patterns as "codes". The codes convey the same exact information that the patterns of wayside signal lights do: basically "clear" (full speed ahead), "restricting", and a couple of intermediate categories. The engineer is still controlling the train, and still has to know the speed limits on a given stretch of track. But when the code gets changed to something more restrictive, a buzzer sounds and they have so many seconds to get in compliance with the speed limit before a brake penalty is applied.

If the X seconds of warning expire with no engineer action applying the brake to slow down to the new speedlimit...the signal system steps up the penalty by cutting out. "Cutting out" means what it implies: the signal shuts off entirely, and no longer makes a circuit. Train loses the signal...it goes into emergency. Loud alarm goes off at the console, and if you do not hit those brakes in a split second the train forcefully does it by itself and a bunch of passengers get a rough jolt and start swearing at your conductor co-workers...who then chew you out. Old Colony, Stoughton, Fairmount, Worcester commuters: you've probably been on trains that have done the rough WTF? slowdowns when the engineer gets slapped by the cab signals.


That's the fail-safe. The train treats it as if there's a problem with the signals and that they've gone totally offline. So you stop, and you can't proceed at >20 MPH until the train picks up a new signal telling it that it can do something else. The simplicity and robustness of the system is that the "Engineer bad!" punishment is the same as the "Hold up! I think we might have a track problem ahead; I can't see the signals!" alert like a broken rail.


The type of PTC system ("A.C.S.E.S.") that Amtrak is installing here--and which has had running New Haven-Boston since '01--is a third layer on top of the track circuits and cab signals. Both of the pre-existing layers still perform all their vital functions, but the RF transponders allow for full 2-way computer communication with the trains to fine-tune things much more precisely and close the last loopholes. The old tech is near-perfect at what it does best, so this flavor of PTC is strictly an augmentation that adds new safety features. If the PTC computers go on the fritz, then you still have the full force of the cab signals backing everything up.


-----------------------------


When they use the term "train went into emergency" in these news reports...that means the engineer blew the signal, did not respond in time, got slapped with an "Engineer bad!" drop-out, did not respond NOW, then the train went into automatic stop. But 106 MPH was way way too fast for the braking maneuver to slow the train enough before it jumped the tracks. 3 seconds, -4 MPH, and then Amtrak's data feed to the locomotive's black box cut out...presumably that was the start of the derailment. The shudder that the was felt throughout the cars before they went flying was probably that emergency braking hitting the start of the curve and tearing out the rail.


You can probably do some complicated maths based on the position of the signal that sent the last penalty and the stopping distance to figure out what kind of upper-bound speed that signal's placement was designed to stop in a worst-case scenario. It certainly was designed for a hell of a lot less an upper bound than 100 MPH...Physics 101 will tell ya that much.

So the question is...how in the hell did this train accelerate to 106 MPH so quickly to elude the previous signal from applying the harshest braking penalty? Because the previous interlocking by North Philadelphia station imposes a 60 MPH limit for a short distance that would've involved a hard penalty. And we know this train wasn't running flagrantly afoul back there. Then in the short distance of 70 MPH territory after N. Philly station but before Frankford Jct. there's 1-2 more intermediate signals that would've started tightening the noose before this last one cut out. You're talking, like, 20-30 MPH acceleration in a third- to half- mile to elude the signals if they were functioning. All while pulling 8 coaches roughly 40% full. If a Sprinter locomotive has ever achieved that kind of acceleration before, it was probably on a Siemens test track. Somehow, some way, this engineer managed to pull that feat off on an exceptionally curvy stretch of the NEC.



Yeah. I can see why that guy's lawyering up to his eyeballs right about now. I mean...wow. We're so cosmically beyond [*puts on Desi Arnaz voice*] "You've got some 'splaining to do" here.
Click to expand...

If Amtrak has a feed of the speed from the train itself, wouldn't a trivial amount of software be able to compare the speed to an allowable speed map? Then you could sound an alarm in the control center or the cab itself?
 
It was also stressed that the Amfleet (AmCans) are more than 40 years old, and have been in service since the early '70s.

Hopefully, this incident, even though it is a sad & tragic one, it might set the stage for installing seat belts in the cars to help save more lives!

Amtrak really needs to start replacing those old aging ancient dinosaur business, coach & cafe cars with newer energy-efficient ones!

And hopefully, the Gov't will realize this and suggest it to them - speeding up the replacement program.


Here's a vid showing the aftermath of the crash on the evening in question;

https://www.youtube.com/watch?v=uTo869nOtZU
 
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The seat belts on trains issue keeps being brought up, but I'm not sure most have really thought it through.

Is the idea that Amtrak trains will have seat belts installed and that passengers will be sort of suggested/encouraged to wear them when at their seats? But will still be permitted to walk around the train (to/from the cafe/restrooms, etc.) as they desire? Or will passengers be required to wear them at all (or most) times?

And what about commuter trains? Surely seat belts are impractical on crush-capacity commuter trains (with passengers standing).

Look, if we want to have seat belts available for passengers to choose whether or not to use them, alright. But I don't think that's the best use of scarce funds. I'd rather we adopt the best practices of other countries in terms of rail safety instead.
 
I doubt will ever see seat belts on trains , but they should be pushed for Buses....which tend to roll over more easier...
 
She's completely right on just about everything she says. Too bad the deadline for PTC will likely be moved back or just flat out ignored.
 
Seat belts on a train seem ridiculous to me. Europe runs more trains than us without needing them for safety we just need to improve our safety standards to be more similar to european railroads.
 
Seat belts on a train are as dumb as snakes on a plane.

Rachel Maddow says everything over and over again except for the fact that Congress did not fund the PTC mandate.

You know, the most important point. Sigh.
 
Matthew said:
Seat belts on a train are as dumb as snakes on a plane.

Rachel Maddow says everything over and over again except for the fact that Congress did not fund the PTC mandate.

You know, the most important point. Sigh.
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Seat belts are a total distraction (they are important in cars because cars are light, put everybody very close to the point of impact, and decelerate or come apart very quickly in a crash). Just not the big problem(s) on a train.

PTC should have been funded, and if State-of-Good-Repair with just a tiny sprinkling of curve straightening had been funded, I'd have to believe that Frankford Junction would have been a top curve-straightening project, being on the map of the worst curves on the NEC, but tops on that list of the ones worth fixing (improvement/$)

If you look at the map above, the B&P Tunnel (Baltimore), Wlimington, Zoo (in Philly) and Elizabeth (in NJ) are bad curves, but not as big a buzzkill because they are close to the terminals at BAL, WIL PHL and NYP. (The B&P is killer-slow, but is its own problem because, to fix it takes a whole lotta nasty tunnel.

But the curves at Frankford and Metuchen are real downers because they come in the middle of nowhere and break up what otherwise would be a very long, very straight stop-free stretch. Just a couple of takings would address them and be really really helpful both for speed and safety.
 
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