What happens in an emergency stop?

[buddy559]

What exactly happens with an emergency train stop. I have watched every video and script available. I understand the basic concept... but, what happens? I have heard the "dump" of air, and the screech.

In examining the accident with the CZ in 2011, The engineer stated he engaged the car brakes, to "streach out the train", prior to the emergency brakes, to avoid a derailment. (I don't totally grasp this concept) I fully believe he saved many lives, just curious, why would that help, (because I do not know) and what may or would have happened had he not done this.

Just trying to learn what happens in an accident. I know, there is no telling when SHTF, but it is amazing, (and horrifying to me) to see how well an issue can happen, like tonight with the crescent, where its just a bother to the passengers, versus, what happened in Bourbanis, IL?

I am also curious, just for a question, in the CZ incident, there was a Non rev employee on board, who assisted with passenger evacuation. (That gentleman needs a medal!) But the rest of the employees who were interviewed just had normal functions to report. Are there no formal evacuation procedures on the train cars, no one yelling, Leave everything, come this way, stay low, crawl here, climb out of this burning hole?

My main curiosity is what mechanically happens with the brakes, "flat spots in the wheels" I guess they just lock down, is there no anti lock breaking? or is there?

I am also curious as to the role of the conductor. From what I have read, they are held to the grindstone for anything with the train operation, but they are not, at the controls of the locomotive? How do they...???(sleep at night??) I couldn't with that pressure, and no control.

I am just facinated with the whole concept, and I can't wait to be on a train, that will roll all the way across the country on a dedicated track, and wow! How do they do it???

 

[John Bobinyec]

The main problem with braking is uneven braking. Ideally, the brakes on each car will apply the exact same retarding force as every other car in the train. If that could happen, then no forces would be experienced between the cars. As it is, if the brakes go on the front first, and the forces are too great, then as the rear end runs into the front end, damage can occur, including a derailment, as a car in the middle gets "squeezed" off the track. On the other hand, if the brakes go on the rear first, and the forces are too great, then the train can be pulled apart, with damage and possibly a derailment as well. And if the brakes are malfunctioning on one car such that they are applied on only that car, then flat spots in the wheel tread can occur as the wheel is slid along the rail, or the brake shoes can melt and deposit metal on the wheel tread, leading to further damage, possibly.

jb

 

[pianocat]

There is a Facebook page dedicated to CZ accident in summer of 2011. It's called: Amtrak California Zephyr Memorial Page. Reno Nevada Wreck... If you scroll back far enough, you will find many articles and accounts of crew and pax from that disaster, first hand accounts of how they handled the emergency. Fate intervened for me, I was on this train but had just gotten off at Salt Lake City about 7 hours before the accident.

 

[buddy559]

Thanks! So are flat spots the result of ineffective braking? Like in the locomotive, when the hit the kill switch, does the whole train, cars and all, start a sequence of braking to take up the slack. Sorry for wandering just can't wrap my head around it yet. jb, when you say , if the rear cars brake too much they can be pulled apart, would they just grind to a stop or?

I have to say as a lay person, I would not have realized, untill watching those you tube videos, how long it takes to stop, and how heavy a train really is. Not that I would have played with it, just haven't had the experience with it. (I just haven't been around tracks much, just at grandma's place, and then we would crawl up and put pennies on the track and crawl back.)

I know the circumstances are vast, but trying to learn a general understanding about how trains work. (Reading about the traction motors, etc. why do the wheels not slip , brain not ready i guess)

 

[buddy559]

There is a Facebook page dedicated to CZ accident in summer of 2011. It's called: Amtrak California Zephyr Memorial Page. Reno Nevada Wreck... If you scroll back far enough, you will find many articles and accounts of crew and pax from that disaster, first hand accounts of how they handled the emergency. Fate intervened for me, I was on this train but had just gotten off at Salt Lake City about 7 hours before the accidentSo

So glad you are well! My heart breaks for the conductor who lost her life. I have a special place for people who loose their life in the line of duty, it is so tragic, i just can't deal. In my research, I guess she had a house in south lake, which was 2 streets over from my pilot friend. I have read the NTSB reports for the incident, and it is just so hard to read anything. (emotionally) I was not trying to say anyone didn't do their jobs, I thankfully never had to deal with that circumstance. I was just wondering if they were given evacuation drills, or commands. At the airlines, we had to perform an evacuation drill once a year, commands word for word, procedures followed to the letter, taking certain equipment out with us, and evacuating last, then tending to passengers, a whole checklist of tasks to perform if physically able.

 

[RailRide]

I have to say as a lay person, I would not have realized, untill watching those you tube videos, how long it takes to stop, and how heavy a train really is. Not that I would have played with it, just haven't had the experience with it. (I just haven't been around tracks much, just at grandma's place, and then we would crawl up and put pennies on the track and crawl back.)

I know the circumstances are vast, but trying to learn a general understanding about how trains work. (Reading about the traction motors, etc. why do the wheels not slip , brain not ready i guess)

This video is the most graphic example I know of that demonstrates how long it takes a freight train moving at a moderate speed to stop in an emergency:

http://www.youtube.com/watch?v=Yihtu-2Okos

The train was in emergency braking mode from the moment it obliterated that semitrailer.

A passenger train wouldn't take quite that long -- I was on the Crescent on 3/25/2010 when its brakes went into emergency about five minutes south of Manassas, VA. I heard a muffled PFOOSH! and a couple of seconds or so later you could feel heavy deceleration of the train, howling to a stop opposite the Broad Run/Airport VRE stop. The culprit was traced to the private car Cripple Creek riding along at the end of our consist.

---PCJ

 

[ALC Rail Writer]

Well for starters, the train comes to a stop.

 

[buddy559]

I have to say as a lay person, I would not have realized, untill watching those you tube videos, how long it takes to stop, and how heavy a train really is. Not that I would have played with it, just haven't had the experience with it. (I just haven't been around tracks much, just at grandma's place, and then we would crawl up and put pennies on the track and crawl back.)

I know the circumstances are vast, but trying to learn a general understanding about how trains work. (Reading about the traction motors, etc. why do the wheels not slip , brain not ready i guess)

This video is the most graphic example I know of that demonstrates how long it takes a freight train moving at a moderate speed to stop in an emergency:

http://www.youtube.com/watch?v=Yihtu-2Okos

The train was in emergency braking mode from the moment it obliterated that semitrailer.

A passenger train wouldn't take quite that long -- I was on the Crescent on 3/25/2010 when its brakes went into emergency about five minutes south of Manassas, VA. I heard a muffled PFOOSH! and a couple of seconds or so later you could feel heavy deceleration of the train, howling to a stop opposite the Broad Run/Airport VRE stop. The culprit was traced to the private car Cripple Creek riding along at the end of our consist.

--

I have to say as a lay person, I would not have realized, untill watching those you tube videos, how long it takes to stop, and how heavy a train really is. Not that I would have played with it, just haven't had the experience with it. (I just haven't been around tracks much, just at grandma's place, and then we would crawl up and put pennies on the track and crawl back.)

I know the circumstances are vast, but trying to learn a general understanding about how trains work. (Reading about the traction motors, etc. why do the wheels not slip , brain not ready i guess)

This video is the most graphic example I know of that demonstrates how long it takes a freight train moving at a moderate speed to stop in an emergency:

http://www.youtube.com/watch?v=Yihtu-2Okos

The train was in emergency braking mode from the moment it obliterated that semitrailer.

A passenger train wouldn't take quite that long -- I was on the Crescent on 3/25/2010 when its brakes went into emergency about five minutes south of Manassas, VA. I heard a muffled PFOOSH! and a couple of seconds or so later you could feel heavy deceleration of the train, howling to a stop opposite the Broad Run/Airport VRE stop. The culprit was traced to the private car Cripple Creek riding along at the end of our consist.

---PCJ

That video is amazing, I am just trying to grab on to help slow it down. I've seen that video from Michigan I believe, the car with 5 kids drives in front of the train. I believed it was released from a state department... to do exactly what it does. Really make you think. I remember several movies and talks in school about the danger of railroad tracks, and how to respect them. Blows my mind to hear of someone walking behind a train and not looking. Look left, look right , then walk. I guess the curriculum has changed, they even taught us how to duck and cover for earthquakes... oh how many hours i spent under my desk.

 

[buddy559]

Well for starters, the train comes to a stop.

Thanks, cause from the other thread i figured they would just keep going and wash off the mess at the next commo station, so the emergency brakes stop the train you say....... interesting.

 

[caravanman]

Broadly speaking, high pressure air is introduced to the brake system to apply brakes... a little air makes for gentle brake application, maximum air asap makes for emergency. I used to drive locomotives here in the U.K. as a trainee many years ago, and the brake air pressure was introduced from reserve cylinders on the locomotive, which meant that the brakes nearest the loco would apply just a fraction first. It could be that nowadays, an instant electrical actuator on each vehicle may even out that slight discrepancy. As far as I am aware, there is no method for an engineer to apply the brakes to the rear of the train before the rest, although he can apply the loco brake only, to bunch up the coaches against the loco. May be different stateside, may be different here nowadays. In the 1970's we ran goods trains with no brakes except on the loco, and the brakes on some trains were operated by letting in air to destroy a 21" vacuum in the pipes, but let's not get nostalgic..

Ed

 

[John Bobinyec]

Broadly speaking, high pressure air is introduced to the brake system to apply brakes... a little air makes for gentle brake application, maximum air asap makes for emergency. I used to drive locomotives here in the U.K. as a trainee many years ago, and the brake air pressure was introduced from reserve cylinders on the locomotive, which meant that the brakes nearest the loco would apply just a fraction first. It could be that nowadays, an instant electrical actuator on each vehicle may even out that slight discrepancy. As far as I am aware, there is no method for an engineer to apply the brakes to the rear of the train before the rest, although he can apply the loco brake only, to bunch up the coaches against the loco. May be different stateside, may be different here nowadays. In the 1970's we ran goods trains with no brakes except on the loco, and the brakes on some trains were operated by letting in air to destroy a 21" vacuum in the pipes, but let's not get nostalgic..

Ed

Curious. Evidently the braking systems here work just the opposite of how they work across the pond.

The following is about US braking systems. The engine supplies air through the trainline to each car. On each car, the trainline feeds air pressure through a triple valve to the air reservoir. Before the train leaves its initial terminal, the brake system is thusly charged up. Once the pressure reaches equilibrium throughout the train, the brakes will be OFF. In order to apply the brakes, the engineer will REDUCE the air pressure in the trainline. The triple valve senses this and allows air to go from the car's air reservoir to the brakes cylinders, applying the brakes. In order to release the brakes, the engineer INCREASES the pressure in the trainline. The triple valve senses this, releases the air from the brake cylinders and replenishes the used air in the reservoir.

This system was designed by none other than George Westinghouse, over a hundred years ago.

The brakes can be applied from the rear by a person, if there is one back there; or a FRED; or a defective brake valve; or a break-in-two. The intent of the system is to apply the brakes if there is a break-in-two.

On passenger trains, the control of the triple valves can be done both by the air pressure AND by electromechanical devices, if they are so equipped.

If an engineer initiates an emergency brake application on a freight train, all the air is let out (dumped) from the trainline at the engine. The air pressure reduction travels backward through the train from the engine. The triple valves sense the emergency application and also will vent the trainline air to the atmosphere. If they didn't, all the air would have to leave the trainline via the engineer's brake valve. That would take too long. Even with modern triple valves, it takes a few seconds for the pressure reduction to travel the full length of a long freight train. The result is that the brakes are applied first on the front and progressively later all the way to the back end of the train.

The next generation of brakes will add elecromechanical controls to freight trains, allowing all the brakes to be applied at the same time.

jb

 

[Blackwolf]

Somewhat related, as it shows some of the difference in stopping distance between a short passenger train vs. a long freight, but this video never ceases to absolutely ASTOUND me.

http://youtu.be/l1q9eBaWY3k

Some VERY lucky passengers, and a very stupid train crew on the CP freight who entered the mainline from a spur without gaining a warrant to do so. Obviously this video is old and others here (likely) might know more about the incident, but my understanding is this was in dark territory and that the VIA had been cleared for maximum track speed on that block only minutes before, then rounded a curve to find the headlights of a conflicting freight standing on the same track. At least the CP crew partially redeemed themselves by throwing their train into full reverse and gaining a few precious feet right in the nick of time, or else there would have been a collision.

I'd probably do the same as the engineer; ensure the train is holding in full emergency, broadcast the situation to my conductor and have passengers moved back as quick as possible, and then bail for my life!

 

[caravanman]

JB, It sounds as though you have a better understanding of the air brake system than I do, and I must be wrong... Most of my "hands on" experience was with vacuum braked trains, where the loco sucked air from the train pipe to create a vacuum, and this kept the brakes off. I had assumed that the air pressure for the brakes worked in the opposite way, but can see now that can't be correct, as a break in the air pipe would cause loss of air and no brakes... not the fail safe we need!

No wonder they never promoted me from trainee to engineer...

Ed

 

[Trainmans daughter]

Broadly speaking, high pressure air is introduced to the brake system to apply brakes... a little air makes for gentle brake application, maximum air asap makes for emergency. I used to drive locomotives here in the U.K. as a trainee many years ago, and the brake air pressure was introduced from reserve cylinders on the locomotive, which meant that the brakes nearest the loco would apply just a fraction first. It could be that nowadays, an instant electrical actuator on each vehicle may even out that slight discrepancy. As far as I am aware, there is no method for an engineer to apply the brakes to the rear of the train before the rest, although he can apply the loco brake only, to bunch up the coaches against the loco. May be different stateside, may be different here nowadays. In the 1970's we ran goods trains with no brakes except on the loco, and the brakes on some trains were operated by letting in air to destroy a 21" vacuum in the pipes, but let's not get nostalgic..

Ed

Curious. Evidently the braking systems here work just the opposite of how they work across the pond.
The following is about US braking systems. The engine supplies air through the trainline to each car. On each car, the trainline feeds air pressure through a triple valve to the air reservoir. Before the train leaves its initial terminal, the brake system is thusly charged up. Once the pressure reaches equilibrium throughout the train, the brakes will be OFF. In order to apply the brakes, the engineer will REDUCE the air pressure in the trainline. The triple valve senses this and allows air to go from the car's air reservoir to the brakes cylinders, applying the brakes. In order to release the brakes, the engineer INCREASES the pressure in the trainline. The triple valve senses this, releases the air from the brake cylinders and replenishes the used air in the reservoir.

This system was designed by none other than George Westinghouse, over a hundred years ago.

The brakes can be applied from the rear by a person, if there is one back there; or a FRED; or a defective brake valve; or a break-in-two. The intent of the system is to apply the brakes if there is a break-in-two.

On passenger trains, the control of the triple valves can be done both by the air pressure AND by electromechanical devices, if they are so equipped.

If an engineer initiates an emergency brake application on a freight train, all the air is let out (dumped) from the trainline at the engine. The air pressure reduction travels backward through the train from the engine. The triple valves sense the emergency application and also will vent the trainline air to the atmosphere. If they didn't, all the air would have to leave the trainline via the engineer's brake valve. That would take too long. Even with modern triple valves, it takes a few seconds for the pressure reduction to travel the full length of a long freight train. The result is that the brakes are applied first on the front and progressively later all the way to the back end of the train.

The next generation of brakes will add elecromechanical controls to freight trains, allowing all the brakes to be applied at the same time.

jb

OK, probably a stupid question, but does this have anything to do with the "WHOOP" sound the train makes as it pulls ito a station? I love that sound and have wondered what causes it.

 

[ALC Rail Writer]

OK, probably a stupid question, but does this have anything to do with the "WHOOP" sound the train makes as it pulls ito a station? I love that sound and have wondered what causes it.

Edit I was wrong... air compressor turning on when electric drive motor is warming up. The whoop comes from the motor.

At least that's what this guy said:

http://discuss.amtraktrains.com/index.php?/topic/46101-ditch-lights-cont-the-whoop-noise-and-a-bell/?p=345871

 

[Ryan]

Yep, that's what it is.

 

[Peter KG6LSE]

I was on the CS 11 a week ago ..... We hit the E brakes while at full tilt . Lets just say It was a VERY un eventfull stop.

I really felt nothing too bad Granted I was heading down the stairs in the cafe car .

I kinda fell back but Really thought nothing off it . . Only when the LSA said . Well we dumped air We must have hit something did I put the rather fast stopping with the noise of air .

Peter .. we did have a FPH59( in cascade liverty ) on slot #2 after the normal genesis on point .

I wonder If that any bearing to the nice stop we had .

ends up the ped whom was crossing was OK but had the death scared outta him .

 

[rrdude]

I have to say as a lay person, I would not have realized, untill watching those you tube videos, how long it takes to stop, and how heavy a train really is. Not that I would have played with it, just haven't had the experience with it. (I just haven't been around tracks much, just at grandma's place, and then we would crawl up and put pennies on the track and crawl back.)

I know the circumstances are vast, but trying to learn a general understanding about how trains work. (Reading about the traction motors, etc. why do the wheels not slip , brain not ready i guess)

This video is the most graphic example I know of that demonstrates how long it takes a freight train moving at a moderate speed to stop in an emergency:

http://www.youtube.com/watch?v=Yihtu-2Okos

The train was in emergency braking mode from the moment it obliterated that semitrailer.

A passenger train wouldn't take quite that long -- I was on the Crescent on 3/25/2010 when its brakes went into emergency about five minutes south of Manassas, VA. I heard a muffled PFOOSH! and a couple of seconds or so later you could feel heavy deceleration of the train, howling to a stop opposite the Broad Run/Airport VRE stop. The culprit was traced to the private car Cripple Creek riding along at the end of our consist.

---PCJ

Now, I've seen a TON of videos on train car/truck collisions, and have personally been involved in two, (I was on the train) but THAT is a great video, showing the speed, braking, and utter destruction, while at the same time, (I assume) no fatalities.

 

[rrdude]

Usually when a PAX train dumps the air, the only thing one might notice is a rather abrupt stop, unless it is followed by a collision, or the train hitting the ground. (ties really DO sound like they are getting chewed up, and I guess they are, in a way)

 

[Bill Nash]

Anyone with an extreme fascination about how a train works should consider buying this book ...

http://www.amazon.com/Railroad-What-Does-Introduction-Railroading/dp/0911382585

Be sure to get the latest, Fifth Edition, things have changed over the years.

 

[NW cannonball]

Hey thanks Guest_Bill_Nash for the book reminder, probably the classic general source on railroads.

Just bought Powell's only copy, used, paper $35.

About emergency brake application, happened once on the Builder near, not on, Marias Pass 2-3 years back. Air hose parted at a grade crossing - nothing dramatic, just a rapid stop from 79 mph, maybe roughly 1/4 to 1/2 mile to stop, more or less. Conductor had to get out, walk the train, reconnect and secure air hose, brake test, continue on, file report of "unrequested emergency application" with date, time, milepost, speed, notch, amps, etc. maybe 15 minute delay. No flat wheels. Fortunately no pedestrians or vehicles involved. Just an unscheduled test of the e-brakes. They worked well,

 

[chakk]

Wheels do slip at times. And the engines are (still) equipped with sand to spray on the rails to increase traction. Plus the traction motors have a sensing mechanism to momentarily reduce the torque applied to the wheels when the start of a slip is occuring. Not unlike what many modern autos have installed that reduce engine power when slipping of the drive wheels is detected.

First time I encountered this was with a rental car on a snowy day in western Pennsylvania. Didn't realize that there was a "bypass switch" to disable this slip detector, which probably would have allowed me to continue up the short snow-covered hill with slipping a bit as I went along, but eventually getting down to the bare road.

I know the circumstances are vast, but trying to learn a general understanding about how trains work. (Reading about the traction motors, etc. why do the wheels not slip , brain not ready i guess)