Message boards :
Cafe SETI :
train safety
Message board moderation
Author | Message |
---|---|
David S Send message Joined: 4 Oct 99 Posts: 18352 Credit: 27,761,924 RAC: 12 |
I could have put this in the train thread, but it deserves its own. http://www.nscorp.com/nscportal/nscorp/Media/News%20Releases/2013/ns_train_your_brain.html Not that anyone here would be stupid enough to do that, of course. David Sitting on my butt while others boldly go, Waiting for a message from a small furry creature from Alpha Centauri. |
Sirius B Send message Joined: 26 Dec 00 Posts: 24870 Credit: 3,081,182 RAC: 7 |
The graphic billboards are part of Norfolk Southern's Train Your Brain public safety program, which warns motorists and pedestrians of the grave consequences of disregarding railroad signals and trespassing on railroad property. Not really, as it would have been ignored as pics of trains are better! Too many road users are complacent in their thinking! Cars can be "DRIVEN", trains are not! With a vehicle, you can steer it out of trouble, Trains are powered up/down & braked, no steering involved - the tracks steer the train. |
j mercer Send message Joined: 3 Jun 99 Posts: 2422 Credit: 12,323,733 RAC: 1 |
In the Pacific Northwest Amtrak Trains Seattle to Portland have recently raised the speed limits to 79mph through residential neighborhoods all to shave something like 9 minutes off the run. Needless to say folks are upset around here. With summer coming on there will be more deaths. They are knocking down about one a month now. More to come for sure. We still have to many crossing where the gates do not close the road and drivers can make it around the gates. ... |
Sirius B Send message Joined: 26 Dec 00 Posts: 24870 Credit: 3,081,182 RAC: 7 |
However I think it is time that principle was changed. With modern railway disk brakes trains can stop a lot quicker than 50 years ago. Really? You sure about that? You ever heard of Speed & Mass? No matter what braking system is used, it won't stop a train as quick as you think! |
zoom3+1=4 Send message Joined: 30 Nov 03 Posts: 65690 Credit: 55,293,173 RAC: 49 |
The graphic billboards are part of Norfolk Southern's Train Your Brain public safety program, which warns motorists and pedestrians of the grave consequences of disregarding railroad signals and trespassing on railroad property. I agree with Sirius B, this would have been ignored in favor of pictures. The T1 Trust, PRR T1 Class 4-4-4-4 #5550, 1 of America's First HST's |
zoom3+1=4 Send message Joined: 30 Nov 03 Posts: 65690 Credit: 55,293,173 RAC: 49 |
However I think it is time that principle was changed. With modern railway disk brakes trains can stop a lot quicker than 50 years ago. Yep. Probably at least a mile. The T1 Trust, PRR T1 Class 4-4-4-4 #5550, 1 of America's First HST's |
Bernie Vine Send message Joined: 26 May 99 Posts: 9954 Credit: 103,452,613 RAC: 328 |
Railway tracks have the same signalling system that road users do, i.e. red, amber, and green. The railways call them signals, the roads call them traffic lights. The red green and amber is not universal, as I am sure David can confirm, different railroads in the US use different systems. In the UK we use the "block system" trains are separated by an electrically isolated block of track. Also in the UK green means you can proceed at maximum line speed, a green signal would only change to red in an extreme emergency. Single amber means the next signal is red proceed at half line speed. In a 4 aspect system a double amber means the next signal is amber be prepared to slow at next signal and of course red means stop. The amber, and red signals can change as the train approaches. A fully laden UK freight train at 40 MPH can take up to a half mile to stop, so I am afraid the only answer is to phase out all vehicle crossings. If you want the full picture go here http://en.wikipedia.org/wiki/UK_railway_signalling |
Sirius B Send message Joined: 26 Dec 00 Posts: 24870 Credit: 3,081,182 RAC: 7 |
Correct. In the UK at least, Amber is not a stand-alone signal but a repeater of the signal ahead. |
rob smith Send message Joined: 7 Mar 03 Posts: 22149 Credit: 416,307,556 RAC: 380 |
However I think it is time that principle was changed. With modern railway disk brakes trains can stop a lot quicker than 50 years ago. Chris is correct - with modern braking systems the stopping distance for trains has been reduced quite considerably. We did one test where we stopped a train from 160kph to zero, then accelerated back to 160kph in less distance than an A4 with 12 on took to stop from the same speed. I can say it was "not comfortable" for those in the train, but it was spectacular! (Oh, and we didn't slide at all during the stop) Bob Smith Member of Seti PIPPS (Pluto is a Planet Protest Society) Somewhere in the (un)known Universe? |
Sirius B Send message Joined: 26 Dec 00 Posts: 24870 Credit: 3,081,182 RAC: 7 |
Interesting & what was the stopping distance on that test? |
rob smith Send message Joined: 7 Mar 03 Posts: 22149 Credit: 416,307,556 RAC: 380 |
Something in the region of 900m - I've not got my notes at home (not bad for a 500 tonne plus train) Bob Smith Member of Seti PIPPS (Pluto is a Planet Protest Society) Somewhere in the (un)known Universe? |
zoom3+1=4 Send message Joined: 30 Nov 03 Posts: 65690 Credit: 55,293,173 RAC: 49 |
However I think it is time that principle was changed. With modern railway disk brakes trains can stop a lot quicker than 50 years ago. I think that's for a passenger train, from what I've read, here in the US freight trains can be about 15,000 tons, depending on what the contents of the train are of course, as mentioned Here. The T1 Trust, PRR T1 Class 4-4-4-4 #5550, 1 of America's First HST's |
Sirius B Send message Joined: 26 Dec 00 Posts: 24870 Credit: 3,081,182 RAC: 7 |
Something in the region of 900m - I've not got my notes at home (not bad for a 500 tonne plus train) That's not bad at all. Still wouldn't like to be in the way :) |
Donald L. Johnson Send message Joined: 5 Aug 02 Posts: 8240 Credit: 14,654,533 RAC: 20 |
Something in the region of 900m - I've not got my notes at home (not bad for a 500 tonne plus train) Okay, that's about half a mile, but as Vic pointed out, freight trains in the US can be two to three times that heavy. Even with 3 or 4 engines applying braking power, 1/2(mv^2) still applies. Trains CANNOT stop as fast as cars. Donald Infernal Optimist / Submariner, retired |
Gary Charpentier Send message Joined: 25 Dec 00 Posts: 30593 Credit: 53,134,872 RAC: 32 |
However I think it is time that principle was changed. With modern railway disk brakes trains can stop a lot quicker than 50 years ago. The coefficient of friction of a steel wheel on a steel rail hasn't changed. But the coefficient of friction of a modern tyre on a road has. As to "disc" brakes, perhaps on electric light rail passenger service, but they don't exist on freight. In an emergency stop the brakes can cease wheel rotation. Railroads don't like that as it flat spots their wheels and causes excessive wear on the rails. The train will still slide a mile. Finally the amount of energy needed to get a freight train up to speed is a lot more than you think. Shame to waste it to stop for a car to cross the tracks. For some idea of the forces involved http://en.wikipedia.org/wiki/2008_Chatsworth_train_collision |
Bill Walker Send message Joined: 4 Sep 99 Posts: 3868 Credit: 2,697,267 RAC: 0 |
Around here a busy rail crossing sees dozens or hundreds of cars per hour, and maybe 20 or 30 trains a day. And most of those are very long and heavy freights (thousands or tens of thousands of tons). Stopping a train for a car would be very impractical, if not impossible. As Bernie said, the long term solution is to get rid of level crossings (as we call them hereabouts). All that takes is time and money. A short term solution used hereabouts is to limit train travel to off-peak road traffic hours. |
Sirius B Send message Joined: 26 Dec 00 Posts: 24870 Credit: 3,081,182 RAC: 7 |
Leaving aside the matter of friction, after all, the thread is about train safety. The link you provided is highly interesting from a safety POV. It was proven that the engineer of the Metrolink train passed a signal at red because he was "texting"....... ...Was he also deaf? On our trains (mainline as no need for audible alarms on the Underground as the tripcock enters play if one passes a red signal), an audible alarm is given if a train passes a red signal - as Metrolink didn't have their whole system on ATS, surely audible alarms were in place? If not? Why Not? Is it possible that your favourite term applies here? You know, that shareholder thingamejob where profits come 1st! |
zoom3+1=4 Send message Joined: 30 Nov 03 Posts: 65690 Credit: 55,293,173 RAC: 49 |
Around here a busy rail crossing sees dozens or hundreds of cars per hour, and maybe 20 or 30 trains a day. And most of those are very long and heavy freights (thousands or tens of thousands of tons). Stopping a train for a car would be very impractical, if not impossible. Down in Alhambra CA and San Gabriel CA, the trains are down in a trench, better than at ground level like when I was growing up. The T1 Trust, PRR T1 Class 4-4-4-4 #5550, 1 of America's First HST's |
W-K 666 Send message Joined: 18 May 99 Posts: 18996 Credit: 40,757,560 RAC: 67 |
Uk Mainline trains have audible warnings in the cab. AWS. Is the old system (1970's) which I believe is being superceded, because it is not a failproof system. It sounds a buzzer, and a visual indicator, when passing an amber signal. Failure to acknowledge this applies the brakes and stops the train before the red signal ahead. The visual signal remains visible until passing a clear signal. |
Gary Charpentier Send message Joined: 25 Dec 00 Posts: 30593 Credit: 53,134,872 RAC: 32 |
Is it possible that your favourite term applies here? You know, that shareholder thingamejob where profits come 1st! Metrolink is a quasi-governmental agency, no shareholders, just taxpayers. However the operator Veloia Transportation a Transdev Company is a for profit and not an American company. |
©2024 University of California
SETI@home and Astropulse are funded by grants from the National Science Foundation, NASA, and donations from SETI@home volunteers. AstroPulse is funded in part by the NSF through grant AST-0307956.