Emergency Cord

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Er, I know normally when the hoses separate they let the air off and the brakes come on, but what about at the end of the car? Do they like back connect the hoses, or is there some kind of valve that prevents the unconnected hoses from letting the air off. I have never seen an Amtrak with EOTD/FRED, but I could have missed it. So if the hoses do have a valve that is normally closed when they're not connected, then would pulling the emergency brake let the air out?Yea, It's late and I'm rambling, so sorry :D
Amtrak used to run with FRED back when they were in the freight hauling business, but it's rare to see FRED on the bottom these days as he's not needed if the consist only has passenger cars. The AT I believe still runs with FRED, thanks to the car carriers, but that's about it.

In the case where there is no FRED needed, you'll see a short length of hose usually hooked onto the safety bar that prevents you from walking out the rear of the train. That hose has a valve on it that keeps the air in and the system charged. When a train is backing up, you'll see the conductor holding that hose and valve, just he case he has to put the train into emergency.

If one were to add a car on the rear of the train, one would first disconnect that short lenght of hose from the mainline. Then couple the cars up and connect their two hoses together. The short lenght of hose would then be moved to the last car to close the system.

Hence why I said, if you have a seperation, the air should drop out of the entire train unless something has gone majorly wrong and the system has somehow bled out or something gummed up the works such that the hose at the seperation point was clogged. Only in the latter case would pulling the emergency cord do any good.

But you'd really be beating the odds to not only have a seperation, but to have a seperation right at the point where the hose somehow got clogged or stopped. And the odds are that the engineer would have noticed such a clog/stopped problem long before any seperation could occur. He'd have problems stopping the train along the way.
 
That kind of attitude leads to inaction, which is worse than doing something. The bystander effect kills.
Sadly, in the previous comments a hypothetical fight/murderer was mentioned as an on-board scenario. Sadly, more than 90% of people will just run away or ignore such a situation. A fair number of people here said that they would evacuate the train, which is all fine and good, except for the people who have been cornered by or already slain by, Amtrak Johnny.

The somewhat recent Greyhound bus murder, where the asian guy used a "rambo knife" to kill a seatmate, and out of a busload of witnesses, no one tried to stop him. All the passengers and driver fled the train, and then were praised as being "heroic" for leaving the train and later disabling and barricading it to lock the murderer in. During this time, the nutcase severed the head of his former seatmate and ran around with it, taunting police and passengers outside.

"Evil will prevail when good does not stand against it" :(

Sometimes, I wonder how police don't have more "accidental" shootings when apprehending suspects. You're running around with a knife 1/4th your height, wailing like a banshee, and carrying around a head, so we'll just arrest you and shove you in a jail with climate control, 3 free meals a day, a free gym, and HBO? I don't think so, though I already know that I wouldn't make a good police officer.

Again, the people who cut and ran were lauded, and a guy was hacked to death right in front of them. When "heroes" set new land speed records in fleeing from trouble that they could have easily stopped, my hope for the world goes down the drain.
I think you have things a bit mixed up. You mention the unfortunate killing on a bus and then reference people leaving a train! I am not sure what you would have done in the face of an obviously disturbed and most likely psychotic person with a large knife, but I know I probably would not have tried to disarm the nut case in the interest of self preservation. I am not (nor are most people) trained to take this kind of action and I doubt if you are either. The world will be OK without most people acting like a super-hero!
I have opinions on both of your arguments. I would like to think that I would be able to step in and be "the super hero" in a situation like the Greyhound incident. However, without being in the situation I can't say for sure what I would do. I do know what it is like when the fight or flight response kicks in, and depending on the situation, most people will run.

What would the world be like if the passengers of flight 93 hadn't taken matters into their own hands? Should they have waited for trained people to help them? These days, I think we need to be more vigilant and be prepared to step in.
Since someone mentioned the Long Island masacre on the LIRR train, let me mention that's exactly what did happen. Even as some people were running to the next cars, several others took their lives into their own hands and jumped onto the maniac with gun and subdued him. I believe that one of the heros was actually shot, although I don't think that he died.
 
Let me also point out that the RED EMERGENCY EXIT HANDLES on windows are not curtain pulls. On a recent southbound Surfliner some female twit was bothered by the sun, said "Let's lower the curtain," and yanked on the RED EMERGENCY EXIT HANDLE.
Oh, please, that old "passenger thought it was the window shade/curtain" canard has been around forever. The handle is nowhere near the window, and this tired old urban legend has been around the track more times than anyone can remember. Let's not repat it here.
Um, I'm pretty sure that Patrick isn't pulling our leg here and that he did indeed witness this person pull on the red emergency exit handle for the window.

And even though this topic in general is about the emergency cord, in this case we're not talking about the emergency cord. We're talking about the emergency escape for the window. So that handle has to be by the window, since it releases the window from the frame such that one can pull the window out and escape from the train.
 
To elaborate on what Alan said, a train that is only running with passenger cars does not need a FRED. In between each car and the engines there are a few cables/connections. One of these is obviously the air hose that allows the brake system to operate (every railroad car, freight or passenger has this). The others that are passenger train specific are the HEP jumpers and the COMM cable. The HEP jumpers provide electricity to the train generated by the locomotive. The COMM cable communicates between each car and lets the computer on the engine know that everything is functioning with it (Miami Joe, wherever he is, or Dutch could probably provide more insight on this). But I do know that having this cable makes it so that the FRED isn't necessary.

FRED's job is to take readings from the air hose and communicate via radio to the engine what the pressure is. It communicates this data similar to a modem over a phone line, through encoded data signals. Many railfans will program the FRED frequencies into their scanners to pick up freight trains that might not be calling signals. The FRED will chirp every minute or so, or anytime there is a change in the air pressure. This information is displayed in the cab on the computer screen (or on a box in older engines without computer displays). Since the Auto Carriers on Auto Train are essentially freight cars they do require a FRED.

The only other cable present on some passenger trains may be an MU cable. If a train is going to operate in push-pull (Keystone, Vermonter, Shuttles, San Joaquin, Capitol Corridor, Surfliner, etc.) there will be an MU cable. This carries the information from a cab-car/engine to the engine on the rear of the train for things like throttle, air brakes, etc.
 
Let me also point out that the RED EMERGENCY EXIT HANDLES on windows are not curtain pulls. On a recent southbound Surfliner some female twit was bothered by the sun, said "Let's lower the curtain," and yanked on the RED EMERGENCY EXIT HANDLE.
Oh, please, that old "passenger thought it was the window shade/curtain" canard has been around forever. The handle is nowhere near the window, and this tired old urban legend has been around the track more times than anyone can remember. Let's not repat it here.
Scroll up in this thread, Mr. or Ms. Skeptic, and click on the links that show it's no urban legend. A weak mind is a terrible thing.
 
Provided that the brake provides enough force to lock the wheels, the weight of the train does not have a direct impact on stopping distance.
The distribution of mass has an effect, as it changes the all important center of mass.

For more information:http://crpit.com/confpapers/CRPITV3Barney.pdf . Herein, the difference between the 2 levels of brake force are used to ensure that the wheel locks, which is still the fastest way to stop a rolling wheel in ideal conditions.

Just in case anyone has a physics test coming up ;)
I lurk here a lot but don't really post, but I don't think locking wheels is the fastest way to stop.

To maximize braking force, you want to maximize the coefficient of friction (COF) between the two surfaces. There are two COFs for every material pair (in this case, steel on steel); the static COF and the kinetic COF. The static COF is for two objects touching each other but not sliding (a rolling wheel), and the kinetic COF is for two objects in contact but sliding (locked wheel). The static COF is always higher than the kinetic COF. For steel, the commonly accepted values are 0.7 for the static COF and 0.6 for the kinetic COF. (Source) You calculate your friction force by multiplying the COF times the vertical force, in this case the weight of the railcar. The coefficient of friction is basically the percentage of the vertical force (weight) that can be transfered to a horizontal force to restrict the relative motion of between two objects.

Assuming a weight for a superliner coach of 148,000 lbs (via wikipedia), the maximum possible friction force, in this case the force slowing the railcar, for the wheels braking but still rotating is:

Ffs = COPs x Weight -> 0.7 x 148000 = 103600 lbs

and for all wheels sliding would be:

Ffk = COPk x Weight -> 0.6 x 148000 = 88800 lbs

This calculation, although simplified, shows that you can generate a higher braking force if you do not lock the wheels. The same holds true for acceleration, you want to eliminate wheel slip to maximize cohesion (friction again!) and acceleration. Braking is just the same, but deceleration. This is the reason that cars have anti-lock brakes, they keep the tire from sliding to maximize the coefficient of friction between the tire and road. If there is a reason with railcars that this does not hold true, I would be interested in hearing, but I believe this should hold true for any rolling wheel and solid surface.
 
I certainly think that if one can find a crew member quickly, letting the crew handle things is the right plan.
If I were at the back of the last car of a train, and there was a fire in that car that was spreading towards the rear of the train that looked likely to engulf me in flames within the next minute, and the fire was preventing me from safely reaching any crew member, it is not clear to me that jumping from a moving train or just waiting to be engulfed by the flames would be a better choice than forcing the train to stop.
Again, I would find it difficult to imagine that with such a fire, that not one single Amtrak crew member would be aware of it. It is not that you personally need to find a crew member, just that a crew member is aware of the emergency, and will implement the actions they were trained to implement.

If we are inventing scenarios, I could venture one where pulling the cord would cause several people to fall, hitting their heads, and becoming unconscious. It isn't easy escaping an emergency, nor to follow crew member's instructions, if you are uncounsious. :rolleyes:
 
I lurk here a lot but don't really post, but I don't think locking wheels is the fastest way to stop....
Thanks for explaining. As a motorcyclist I hear all the time the "I laid the bike down to stop" fallacy, or "locked up the rear end" story and wince every time.
 
This calculation, although simplified, shows that you can generate a higher braking force if you do not lock the wheels. The same holds true for acceleration, you want to eliminate wheel slip to maximize cohesion (friction again!) and acceleration. Braking is just the same, but deceleration.
You also want to avoid either situation, locked wheels or wheel slip, as much as possible as both cause flat spots on the wheels and can damage the rails too.
 
I lurk here a lot but don't really post, but I don't think locking wheels is the fastest way to stop....
Thanks for explaining. As a motorcyclist I hear all the time the "I laid the bike down to stop" fallacy, or "locked up the rear end" story and wince every time.
Motorcyclist: I think the honest statement would be more like, "I unintentionally laid the bike over and therefore slid to a stop, donating considerably skin to the street in the process."

Actually, for rail wheels, a locked wheels emergency brake stop may end up being faster because you develop flat spots on the wheels which increases your area of contact. Not really a good thing unless you make you money running the wheel lathe.

Alan: generally wheel spin will not give you flat spots on the wheels, but it can give metallurgical damage. It will give you "wheel burns" on the rail head, which if not ground down will quite commonly result in rail breaks, maybe not initially, but ultimately.
 
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Motorcyclist: I think the honest statement would be more like, "I unintentionally laid the bike over and therefore slid to a stop, donating considerably skin to the street in the process."
Actually, for rail wheels, a locked wheels emergency brake stop may end up being faster because you develop flat spots on the wheels which increases your area of contact. Not really a good thing unless you make you money running the wheel lathe.

Alan: generally wheel spin will not give you flat spots on the wheels, but it can give metallurgical damage. It will give you "wheel burns" on the rail head, which if not ground down will quite commonly result in rail breaks, maybe not initially, but ultimately.
last engineering note of the day:

I will mention that, at least theoretically, contact area has no bearing on friction force. In practice that might not always be true, because you may not have perfect contact which is assumed in the calculation. So, it may end up being a crap shoot which is actually better for braking performance.

Also, if you check out the graph at this link its shows a graph of coefficient of friction (vertical axis) vs. applied force (horizontal axis, and in this case, braking force)

The diagonal line represents the static coefficient of friction, which increases with braking (applied) force. The end of that line where it drops down (marked fl on this graph) represents the moment of wheel lock and slipping. The horizontal line to the right represents the kinetic (slipping) coefficient of friction, which is constant. It shows that as your braking force increases, so does your coefficient of friction as long as the wheels are rolling. You only get the benefit of increased braking ability if you can control the brakes to a degree that you are able to get above the horizontal static coefficient of friction line (fk on this graph). You really want to be right at the point before the line drops down; you realize maximum braking ability at impending wheel lock. ABS systems in cars keep your wheels right at this point on the graph.

I imagine a skilled engineer is able to feel when they are getting to that frictional limit, and can module the brake pressure to keep the wheels rolling in normal conditions.

I think thats enough engineering fun for one day!

edited to add: engineering fun is an oxymoron!
 
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I lurk here a lot but don't really post
Hope you'll add more posting to your lurking. While I'd never claim to understand all the technical stuff you've provided, I do get enough of it to be better informed about the principles involved, and that's always good.
 
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Just out of curiousity, what amount of pressure is the air used to apply the airbrakes pressurized too?
 
Just out of curiousity, what amount of pressure is the air used to apply the airbrakes pressurized too?
This seems to be a pretty good overview, and hopefully answers the question:

Train Air Brake Description and History

It does not include the latest development, which is a system whereby all brakes on a train are activated simultaneously.

EDIT: The catch with the new system is that the entire train - locomotives and all cars - must be equipped with it. Otherwise no go.
 
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Just out of curiousity, what amount of pressure is the air used to apply the airbrakes pressurized too?
Are you talking freight, pax or both? Most freight trains are 90 psi while I believe Amtrak runs in the 110-120 psi range. We had a fellow run up the feed valve on a freight train as a joke to 120 psi and air hoses started popping throughout his train. His conductor was not a happy camper as he had to bleed down the entire train while changing air hoses. And one notation~ it is the LACK of air that sets up the brakes. You charge the train line to a certain psi and then draw down from that point to set your brakes.
 
You should only pull the cord if someone is caught in the door and being dragged.
You don't pull it for a medical emergency (find a conductor), you don't pull if for a fire (you move to another car), and you don't pull it becuase you missed your stop.
The Eschede train disaster probably could have been prevented if the emergency cord had been pulled.

IIRC, One passenger noticed the wheel sticking through the floor, and was going to pull the emergency brake, but was warned against it by the conductor.
 
I lurk here a lot but don't really post, but I don't think locking wheels is the fastest way to stop.
Googling around, I ran into this, which may be of particular interest to our engineering-inclined friends as well as others. The website is called Patent Storm.

US Patent 5109343 - Method and apparatus for verification of rail braking distances

Registration is necessary to view the full PDF file, but I've taken care of that for AU folks:

Username: IdiotPatrick

Password: 5-4baby3-2-1

Password is a countdown that was used in punk rocker days to start songs. As opposed to 1-2-3-4... Neither username nor password bear any resemblance to anything I actually use, so no sweat on that score.

May be very slow to load. Patience. Even as a layman I think it's a very interesting document, though of course I'm in no position to judge its professional merits.
 
You should only pull the cord if someone is caught in the door and being dragged.
You don't pull it for a medical emergency (find a conductor), you don't pull if for a fire (you move to another car), and you don't pull it becuase you missed your stop.
The Eschede train disaster probably could have been prevented if the emergency cord had been pulled.

IIRC, One passenger noticed the wheel sticking through the floor, and was going to pull the emergency brake, but was warned against it by the conductor.
and the "its company police not to stop the train until the conductor as investigated the problem" held up in court as the crew on the train were charged with murder or something.
 
To elaborate on what Alan said, a train that is only running with passenger cars does not need a FRED. In between each car and the engines there are a few cables/connections. One of these is obviously the air hose that allows the brake system to operate (every railroad car, freight or passenger has this). The others that are passenger train specific are the HEP jumpers and the COMM cable. The HEP jumpers provide electricity to the train generated by the locomotive. The COMM cable communicates between each car and lets the computer on the engine know that everything is functioning with it (Miami Joe, wherever he is, or Dutch could probably provide more insight on this). But I do know that having this cable makes it so that the FRED isn't necessary.
FRED's job is to take readings from the air hose and communicate via radio to the engine what the pressure is. It communicates this data similar to a modem over a phone line, through encoded data signals. Many railfans will program the FRED frequencies into their scanners to pick up freight trains that might not be calling signals. The FRED will chirp every minute or so, or anytime there is a change in the air pressure. This information is displayed in the cab on the computer screen (or on a box in older engines without computer displays). Since the Auto Carriers on Auto Train are essentially freight cars they do require a FRED.

The only other cable present on some passenger trains may be an MU cable. If a train is going to operate in push-pull (Keystone, Vermonter, Shuttles, San Joaquin, Capitol Corridor, Surfliner, etc.) there will be an MU cable. This carries the information from a cab-car/engine to the engine on the rear of the train for things like throttle, air brakes, etc.
There are actually generally two air hoses between passenger cars, the standard brake pipe and a main reservoir cable from the locomotives. The End Of Train device provides the engineer with a brake pipe reading on the rear of the train, the ability to trigger an emergency application of the brakes from the rear of the train and serves as a marker.

The difference between an emergency and service application of the train’s brakes is determined by the rate of reduction of the brake pipe. An emergency application is, I believe 120% of the standard maximum application. After an emergency application is triggered, power developed by the locomotives to the wheels automatically is eliminated due to a Pneumatic Control Switch. Only after a train is stopped can the brakes be recovered and power sent to the traction motors.

Alan's mention of the back-up hose is not required to terminate the brake pipe. Each car is equipped with an angle **** which can be closed like a spigot allowing pressure on the train line to build. The back up hose provides an audible warning signal and the ability to trigger an emergency brake pipe application at the rear of the train for shoving moves.
 
Wow!! This is is quite the thread!!! I think I will ask the conductor On the EB when I ride in March " Where the

emergency cord is (just in case) " Then see what his reaction is :lol:

Since I started this thread You can pull the cord anytime!!!! :)

Thanks for the responce!!

Trainfan
 
Wow!! This is is quite the thread!!! I think I will ask the conductor On the EB when I ride in March " Where theemergency cord is (just in case) " Then see what his reaction is

Trainfan
Just post the location where your going to ask and when you're going to ask so you can arrange with another RF on this forum to rescue you when you get kicked off the train! :huh: ..... :lol:
 
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