Metro-North train hits car on crossing

[Via Bank]

Grim news from New York State this morning:

A crowded Metro-North Railroad train passing through Westchester County at the height of the evening rush on Tuesday slammed into a sport-utility vehicle on the tracks at a crossing, creating a fiery crash and explosion that killed seven people, injured a dozen and forced the evacuation of hundreds. It was the deadliest crash in the railroad’s history.

Passengers were temporarily stranded after evacuating the train, as its front car continued to release billowing smoke into the cold night air. Service was suspended on the Harlem line on Tuesday night as firefighters responded to the smoking car and officials said they were investigating what had led to the crash.

The train hit the S.U.V., a black Jeep Cherokee, in the crossing at Commerce Street in Valhalla, N.Y., around 6:30 p.m., officials with the Metropolitan Transportation Authority said. The driver of the vehicle and six people on the train were killed, Gov. Andrew M. Cuomo said after touring the scene late Tuesday.

At first glance it looks not unlike the Ufton Neveret crash or Glendale (although obviously we can expect more light to be shed on this in the future.) Awful either way.

 

[edwin_m]

http://www.bbc.co.uk/news/world-us-canada-31124170

The crossing gates at the railroad had come down on top of the vehicle, which had stopped on the tracks, Metro-North Railroad spokesman Aaron Donovan said.

The driver got out to look at the damage, and then got back into the car to drive forward before it was hit by the train. It pushed the vehicle more than 120m (400ft).

It is not yet clear why the vehicle stalled on the tracks.

As a result of the collision the electrified third rail of the track came through the front carriage of the train.

Alarming that there was obviously a severe fire inside the first car (though the appearance of the whole car being burnt out may just be smoke damage). According to the fleet number it is an EMU so the tank of the Cherokee is the only obvious source of fuel. Interesting comment also on third rail - according to Wikipedia this is the only third rail section with grade crossings on the network.

 

[John Webb]

.....Alarming that there was obviously a severe fire inside the first car (though the appearance of the whole car being burnt out may just be smoke damage). According to the fleet number it is an EMU so the tank of the Cherokee is the only obvious source of fuel.......

Looks to me as though the seating in the coach caught fire - either the third rail caused arcing inside as it penetrated or, more likely, the penetration allowed fuel from the car to get inside the coach where it ignited the seats.

I suspect that most of the video is showing steam rather than smoke as fire-fighters complete extinguishment - the 'smoke' issuing looks too white for plastics etc burning and it was obviously a cold evening, which would make the steam more prominent.

 

[MarlowDonkey]

The report on the level crossing crash on the New York metro mentions something never seen in the UK. They report that

The third rail of the track came up from the explosion and went right through the [rail] car.

http://www.theguardian.com/world/2015/feb/04/new-york-train-crash-kills-six-reports

They are quoting the Governor of New York, so perhaps not entirely accurate?

The electrified third rail of the track tore through the floor of the first car [carriage] of the train, charring the carriage and sending billows of smoke into the air. Damage to the other seven train cars was minimal.

They don't say so, but are they indicating that the level crossing collision derailed the train into the third rail?

It's difficult to tell from the small pictures in the wiki, but it looks as if the third rail is higher off the ground than it would be in the UK on main line systems.

http://en.wikipedia.org/wiki/Metro-North_Railroad

 

[A0]

The report on the level crossing crash on the New York metro mentions something never seen in the UK. They report that
The third rail of the track came up from the explosion and went right through the [rail] car.

http://www.theguardian.com/world/2015/feb/04/new-york-train-crash-kills-six-reports

They are quoting the Governor of New York, so perhaps not entirely accurate?

The electrified third rail of the track tore through the floor of the first car [carriage] of the train, charring the carriage and sending billows of smoke into the air. Damage to the other seven train cars was minimal.

They don't say so, but are they indicating that the level crossing collision derailed the train into the third rail?

It's difficult to tell from the small pictures in the wiki, but it looks as if the third rail is higher off the ground than it would be in the UK on main line systems.

http://en.wikipedia.org/wiki/Metro-North_Railroad

Looking on Googlemaps at crosssings on that line, it appears the 3rd rail is of the 'bottom contact' type as seen on the DLR in the UK, so the rail itself is suspended a few inches above the ground and the collector shoe contacts the underside of the rail. Usually such rails are 'shrouded' so that if somebody steps on them they aren't electrocuted - unlike the standard 3rd rail used on the UK mainline.

Having said that, looking at the area and how 'unsecured' the railway line is, I'm surprised they use 3rd rail at all - I'd have thought OHLE would be safer.

 

[59CosG95]

Looking on Googlemaps at crosssings on that line, it appears the 3rd rail is of the 'bottom contact' type as seen on the DLR in the UK, so the rail itself is suspended a few inches above the ground and the collector shoe contacts the underside of the rail. Usually such rails are 'shrouded' so that if somebody steps on them they aren't electrocuted - unlike the standard 3rd rail used on the UK mainline.

Having said that, looking at the area and how 'unsecured' the railway line is, I'm surprised they use 3rd rail at all - I'd have thought OHLE would be safer.

The line was obviously implemented when 3rd rail was the practicable way forward-the tunnels didn't have OLE clearance most likely.

 

[MarlowDonkey]

Having said that, looking at the area and how 'unsecured' the railway line is, I'm surprised they use 3rd rail at all - I'd have thought OHLE would be safer.

As the third rail would be gapped at the crossing, presumably the third rail speared the rail car assuming it became derailed after the collision. Is that a potential risk with the DLR as well in the event of a derailment, not that there are any level crossings, nor many derailments?

 

[Waddon]

On a similar subject, I often wonder if the use of overhead conductor rail, as is being used in tunnels in some electrification schemes such as Crossrail, could pose a similar risk of piercing the carriage if it came down for some reason?

 

[Murph]

I wonder if the use of bottom-contact third rail contributed to the severity of the New York incident, with the rail being higher off the ground than typical UK top-contact 3rd rail?

With UK style 3rd rail, I imagine that any wreckage will generally tend to slide over the top of it. With a raised 3rd rail (for bottom or side contact), I guess there's a greater chance of wreckage getting under it, or grabbing the end of it, and displacing it upwards.

Obviously that's only a contributory factor for the severity of the incident, not a causal factor.

 

[DownSouth]

From reports, it sounds as if the bottom contact third rail was been pulled out of the ground in the crash - the railcars all stayed upright and so it would have been a penetration from underneath the floor. I'd guess that a top contact third rail, if pulled out of the ground by the tangled wreck of a car being pushed along the tracks, could well do the same thing.

The bottom contact third rail used on Metro-North protrudes only slightly higher than the UK top contact third rail, and it is not as high as the DLR bottom contact third rail.

With that in mind, I'm sure that the relevant authorities in Britain (and other countries still using third rail) will be keeping a close eye on the NTSB investigation, in case there is anything to learn the easy way rather than the hard way on home turf.

 

[edwin_m]

The bottom of the third rail must surely be above the top of the running rails, otherwise the shoes would be wiped out at pointwork? Thus it must be relatively more vulnerable to this sort of incident, where potentially the SUV was pushed into where the third rail restarted after the crossing and was able to detach it and bend it upwards. I think this is much less likely on SR and LIRR style top contact rail where the bottom of the third rail is below the top of the running rails.

Quite why this caught fire so quickly and severely is the big question for me. I would hope the circuit breakers were good enough to cut the power if this happened, though there is always some risk of a partial short circuit remaining live on low voltage systems. Do we know whether the SUV was petrol or diesel fuelled?

 

[theageofthetra]

In the US it would be very unlikely to be diesel. Very few vehicles other than trucks/pickups come with a diesel option.

 

[AM9]

From reports, it sounds as if the bottom contact third rail was been pulled out of the ground in the crash - the railcars all stayed upright and so it would have been a penetration from underneath the floor. I'd guess that a top contact third rail, if pulled out of the ground by the tangled wreck of a car being pushed along the tracks, could well do the same thing.

The bottom contact third rail used on Metro-North protrudes only slightly higher than the UK top contact third rail, and it is not as high as the DLR bottom contact third rail.

With that in mind, I'm sure that the relevant authorities in Britain (and other countries still using third rail) will be keeping a close eye on the NTSB investigation, in case there is anything to learn the easy way rather than the hard way on home turf.

ISTR that the third rail is not only higher than the running rails, but it seems to be about twice the lateral distance from the running rails compared with UK standards.

 

[edwin_m]

In the US it would be very unlikely to be diesel. Very few vehicles other than trucks/pickups come with a diesel option.

Interesting. I'm not an expert here but I believe petrol is much easier to ignite accidentally.

 

[GB]

You are right. Petrol can easily be ignited from a spark hence we have spark plugs or similar in petrol cars.

Diesel needs to either being heated prior, be under great pressure, or aerosolized to get ignition.

 

[A0]

Interesting. I'm not an expert here but I believe petrol is much easier to ignite accidentally.

Correct - it is.

It is possible to ignite petrol from its vapours, which isn't possible with diesel. And it only needs a slight spark / flame to ignite petrol.

If you pour diesel onto something hot though it will ignite - as was seen at the Paddington crash where the diesel came into contact with hot engine.

For any home scientists who wish to test these theories I suggest finding a wide open space and using no more than a thimble full of each.

If you drop a match on the petrol it will ignite, the diesel will probably put out the match.

 

[DownSouth]

For any home scientists who wish to test these theories I suggest finding a wide open space and using no more than a thimble full of each.

If you drop a match on the petrol it will ignite, the diesel will probably put out the match.

If there are no vapours above the petrol, the petrol will also put out the match.

 

[John Webb]

It seems that the car was petrol-fuelled - so much more likely to ignite when spilt.

On the UK top-contact third-rail system, the third-rail has an approach ramp sloping upwards from below rail level, so an object, such as a car, pushed onto it at a level crossing would tend to be deflected upward and over the rail. I wonder if the under-contact third-rail has a raised ramp sloping downwards to the correct level? Such a ramp would encourage an object pushed into it to go under the rail and lift it up......

 

[Murph]

It seems that the car was petrol-fuelled - so much more likely to ignite when spilt.

Personally, I think that's a bit of a red herring. In a high energy, highly destructive impact, there's a strong chance of diesel being vaporised, which recent science suggests can allow explosive deflagration below the normal flash point of the oil. Petrol is normally the more volatile substance, comparing a static bucket of each at ambient temperature and pressure, but energetically vaporised diesel is quite high risk. I.e. I don't believe that the fuel type in the Jeep actually matters all that much, both cases could quite easily result in explosive deflagration.

HSE: Generation of flammable mists from high flashpoint fluids: Literature review (2013)

On the UK top-contact third-rail system, the third-rail has an approach ramp sloping upwards from below rail level, so an object, such as a car, pushed onto it at a level crossing would tend to be deflected upward and over the rail. I wonder if the under-contact third-rail has a raised ramp sloping downwards to the correct level? Such a ramp would encourage an object pushed into it to go under the rail and lift it up......

Yes, that's a very good point about the ramps on the end of the live rails. I don't know for certain, but I imagine that the bottom contact shoes must have a strong spring pushing upwards to give a good contact and avoid arcing when running along the rail. That suggests to me that there has to be some sort of downward ramp at the rail ends to catch the shoe at the uppermost point of its travel and pull it down to the normal bottom of rail height.

 

[edwin_m]

Here's a crossing on Streetview - not sure if it is the same crossing but it's on the same line:

https://www.google.co.uk/maps/@41.0...ata=!3m4!1e1!3m2!1s6hVW0sHzpv46P9MfEPpL-g!2e0

I can't get it to zoom in on the tracks, but the live rail is definitely well above the level of the running rails and I think the underside is "chamfered" where it re-starts after the crossing.

 

[LexyBoy]

If there are no vapours above the petrol, the petrol will also put out the match.

True, but it'd have to be pretty parky: the flash point of petrol is around -40 C (cf +50 for diesel).

 

[Murph]

Diesel mist can explode (rapid subsonic deflagration) below the nominal flash point. It's relatively recent science, and still being explored, but real enough for the HSE to be digging into it. Bottom line is that while petrol might be the easier one to get going, diesel mist from something like a ruptured tank in a high energy crash is also high risk. The recent research says that diesel (and all other similar-ish oils) is not quite as relatively safe as once thought.

Here's what I posted on the other thread for the NY incident:

In a high energy, highly destructive impact, there's a strong chance of diesel being vaporised, which recent science suggests can allow explosive deflagration below the normal flash point of the oil. Petrol is normally the more volatile substance, comparing a static bucket of each at ambient temperature and pressure, but energetically vaporised diesel is quite high risk. I.e. I don't believe that the fuel type in the Jeep actually matters all that much, both cases could quite easily result in explosive deflagration.

HSE: Generation of flammable mists from high flashpoint fluids: Literature review (2013)

 

[3141]

Correct - it is.


For any home scientists who wish to test these theories I suggest finding a wide open space and using no more than a thimble full of each.

If you drop a match on the petrol it will ignite, the diesel will probably put out the match.

I'd add to that - and keep the lid on your petrol container, and keep the container well away from the experiment. You probably would, but people who repeat the experiment a few times, or try out how it works with a larger quantity than they used the first time, may get a bit careless. And you don't want to find out what half a gallon of petrol going up is like.

 

[WatcherZero]

I understand the rail issue has concerned the americans too, they've started an inquiry into it.

 

[edwin_m]

One solution might be a ramp on the approach to where the third rail re-starts, parallel to the third rail and ending higher than the top of it but a little further away from the track so the pickup shoes don't reach it. A vehicle being pushed ahead of a train would probably be lifted up over the third rail instead of getting underneath and dislodging it.

 

[DownSouth]

I understand the rail issue has concerned the americans too, they've started an inquiry into it.

Yes, the NTSB has confirmed that they have opened an investigation into the crash, which over there is not normally guaranteed for a level crossing incident.

These days, national transport safety regulators pay a lot of attention to the investigations conducted by their counterparts in other countries. It's good to be able to pick up on the lessons that others have learned the hard way without having to learn it the hard way yourself.

 

[HSTEd]

Definitely seems to have a ramp.

 

[Groningen]

The railroadcrossing is at 41.086298,-73.788064. The Mercedes that caused the accident was registered in December 2014. In what i read in the USA-media 1 can say that is a kind of suicide. The female driver was on the crossing, when the barriers came down. Got out of the car; got back in; moved the car, when she was hit by the train. Maybe the fact that she did not have this car for so long maybe a factor in the disaster.

 

[DownSouth]

I read reports saying it went something along the lines of this sequence:

1. the back of the car got hit by the descending barrier.
2. she stopped immediately to inspect the back of the car for damage.
3. she got back in the car and attempted, but failed, to move it again.
4. the train hit the car.

That certainly doesn't sound like a suicide attempt to me, more like gross incompetence. But I'm sure this, and the issue of what exactly pulled up the third rail (was it the car wreckage or a derailed bogie?) will be covered in the NTSB report on the crash.

 

[theageofthetra]

In the UK the third rail isn't fixed and is designed to fall off the pots in an accident. Is it the same on the NY system?