Joel N. Weber II
Engineer
I'm a little skeptical that with several resourceful people working together that would necessarily be true.the only way to disarm a person with a sword is either a sharp shooter or a fire hose on full power.
I'm a little skeptical that with several resourceful people working together that would necessarily be true.the only way to disarm a person with a sword is either a sharp shooter or a fire hose on full power.
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.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
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.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.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!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.
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.
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.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.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.
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.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.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.
I lurk here a lot but don't really post, but I don't think locking wheels is the fastest way to stop.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
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.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.
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.I lurk here a lot but don't really post, but I don't think locking wheels is the fastest way to stop....
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.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.
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."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.I lurk here a lot but don't really post, but I don't think locking wheels is the fastest way to stop....
last engineering note of the day: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.
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.I lurk here a lot but don't really post
My apologies, and I stand corrected. I did not read the OP correctly.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.
This seems to be a pretty good overview, and hopefully answers the question: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.Just out of curiousity, what amount of pressure is the air used to apply the airbrakes pressurized too?
The Eschede train disaster probably could have been prevented if the emergency cord had been pulled.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.
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.I lurk here a lot but don't really post, but I don't think locking wheels is the fastest way to stop.
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.The Eschede train disaster probably could have been prevented if the emergency cord had been pulled.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.
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.
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.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.
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: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
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