Van Horn, Texas, and no, you really, really don't want to eat there, ever....
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That was a chilling article. Well worth the hour of time invested. Have we become a slave to technology? At times.
Railroads have a very good safety feature regarding this type of situation. It is called a "pilot"engineer. The two pilots had very little experience with the territory, language, and the plane. Add technology that precise and the arrows did in fact collide.
I am reminded of a conversation in a telescope retail store. An amatuer astronomer engaged in a conversation with two others that were drooling over the latest 10 inch mak with autofind features, enabling them to program in any of 10,000 (or more deep sky objects). The one asked the two "what do you use that for?" The intent of the question was to inquire as to a specific use for galaxies, open clusters, globular clusters, nebulas, doubles, etc.
The two answered in a very patronizing tone it was used to look at far away objects, which could easily be programed into the computer system. At that time the owner walked in, saw the single astronomer and declared "oh my god, where have you been? I have told people about you and they dont believe that someone can actually use a ETX90 on a card table with only charts to find deep sky objects."
The look on the faces of the two astronomers was priceless. They bought into the technology without understanding the basics (and the beauty) of finding your way to the right place in the sky.
Technology can become a distraction and a very dangerous one at that.
Thanks for the link to the article.
ed
edblysardVan Horn, Texas, and no, you really, really don't want to eat there, ever....
Now this is irony. I have been to Van Horn, Texas, quite a few times. And eaten at various places there. I wonder if this was one of them?
RWM
You would remember this one...ever have to wring the grease out of a Whataburger?
The chicken there drips the stuff....and you can't taste the difference between the chicken and the fries...
edblysard You would remember this one...ever have to wring the grease out of a Whataburger? The chicken there drips the stuff....and you can't taste the difference between the chicken and the fries...
Would you like some chicken and fries with your grease?
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
That's unusual?? For West Texas?? It would taste funny if it was not like that!
In the dark, rain, or after 12 hours on duty, they all tend to look pretty much the same . . .
Especially when you combine all three.....
A lot of "meat" to respond to here, so here goes:
Railway Man Head-in-the-cockpit syndrome, lost in the intracacies of managing the electronics. That thought lept to my mind the first day I saw PTC demonstrated to me in service, in the cab of a locomotive, in 2004. Should the engineer be looking out the window or staring at a flat-screen monitor? We were all staring at the screen waiting for it to tell us what to do next. I didn't like that. This still deeply concerns me. I have been striving ever since to simplify, simplify, simplify, the machine, so that the people can do their job without becoming overwhelmed by the complexity of the machine. Same goes for the dispatching console. It's turned into a flashing jukebox of crap laid out by people who have absolutely zero sense of graphics, clarity, readibility, functionality, and efficiency. Why? Because they don't actually use it. Worse, they employ user review groups who consist of cherry-picked people who will deliver the "right" answer instead of the honest answer. The stuff works but it's about as awful as you can get.
That thought lept to my mind the first day I saw PTC demonstrated to me in service, in the cab of a locomotive, in 2004. Should the engineer be looking out the window or staring at a flat-screen monitor? We were all staring at the screen waiting for it to tell us what to do next. I didn't like that. This still deeply concerns me. I have been striving ever since to simplify, simplify, simplify, the machine, so that the people can do their job without becoming overwhelmed by the complexity of the machine. Same goes for the dispatching console. It's turned into a flashing jukebox of crap laid out by people who have absolutely zero sense of graphics, clarity, readibility, functionality, and efficiency. Why? Because they don't actually use it. Worse, they employ user review groups who consist of cherry-picked people who will deliver the "right" answer instead of the honest answer. The stuff works but it's about as awful as you can get.
Yup - good for you and your instincts ! I've read this same criticism about high-end cars - specifically, BMWs and the Japanese imports. I'm convinced that none of this stuff should be designed by manufacturers alone - the design team must include a user from the real-world, who has absolute veto power and is not afraid to yell "That's nonsense !" (or one of the less-acceptable synonyms).
Twenty years ago when I got back into the consulting business one of my first surprises - in the context of stormwater management calculations - was how much time we had to spend on "outsmarting the computer" so that we could take the data we had, input it in the format that the specialized application program demanded, and get results that were 1) correct, verifiable, and defensible, 2) understandable, and 3) presentable to reviewers, etc. That specialty is much better now - but we're still having to play that game with surveying and drafting software (AutoCAD and Eaglepoint, take notice).
When I took the applied engineering course on "Numerical Methods" (computer calculations of odd functions like logarithms, exponentials, modeling, systems, sytems that are modeled by differential equations and/ or integrals, etc.) we spent a lot of time learning how to recognize and quantify uncertaintly and the bounds ("limits") on the possible range of errors, and the better ways / sequences to calculate certain things so that the results weren't containing too much of the uncertainty or "noise" from the data. Every once in a while since then I run into a anomalous result that is caused by one of those poorly-chosen methods (including a hydraulic channel and depth "backwater" calculation program used for floodplain management).
Of course, recall some of the more famous "number busts" of recent memory - the miles vs. kilometer input goof to one of the outer space (or Mars ?) probes, the grinding of the mirrors for the Hubble telescope, the evidently mis-entered navigation data for the Korean airliner (KAL 700 ?) that was shot down by the Russians over the Kamchatka Peninsula in the 1980s, the lbs. vs. kilograms fuel load into the 747 "Gimli Glider" in Canada about a decade ago, and I'm sure many, many, more.
For a long time I had way more time in the right seat of 4 small private aviation aircraft (all different owners - mostly Cessna 172 N7019Q) - than in commercial airliners. The pilot I flew with most was VFR exclusively - to get certified/ rated on IFR would take too much time away from business for him and the airplane. For him, simple was better. Another plane was essentially a flying test bed for avionics (by Narco - I'm dating myself here) that were worth about 3 times what the plane was, but we were able to transit NY Control in heavy fog with no problems. So I've seen both sides of this.
There was a low-speed collision of 2 commuter trains on the Hatboro-Warminster line of SEPTA a couple years ago - the NTSB (or FRA) report on it reads a lot like the railroad version of this aircraft article: newbie operator ran thru a couple red signals and a switch, but the DS didn't notice because the audible alarm function was turned off (because it was always going off), and didn't notice the flashing icon at the bottom of the screen, if I recall correctly. (The other engineer noticed the signal drop to red unexpectedly, stopped her train, figured out what was happening, and was asking for permission to reverse when the impact came, I believe.)
Again I attempt to quote from Robert Townsend in Up the Organization!: "Man is a complicating animal. He simplifies only under extreme pressure. But when you force him, he will, and then will be privately amazed at how good the solution is." (or similar) He also has a lot of similar points to make under the heading of "Computers (and their Priests)" - this is from back in the 1960s, mind you - the key points of which are: 1) If the operation doesn't have its act together on paper, all the computer is going to do is speed up the mess; 2) Companies have gone bankrupt from computerizing too fast; and 3) The systems people love to invent reports and functions that no one has asked for or needs. To anybody who is reading this far - I highly recommend that you get a copy of this book (paperback, under $10). I've also come to know that there are some odd senses of humor in the participants here, and Townsend's book will probably appeal to that part of your personalities as well. (In the addendum to the revised version, he complains about how GE and its executives got off too lightly when convicted of selling defective jet engine parts - and then were able to deduct the fine for same. As he said: "We don't need to worry about the Russians destroying us - we've perfected 'do-it-yourself' methods !")
As example of the problems that encouraging a machine to do too much creates, I just spent 30 minutes answering a very simple question: "What happens when a locomotive can't ping its GPS satellite, and it's stationary?" It's not a simple answer -- it took me 1,000 words just to outline the basic outcomes. The short answer is: It doesn't result in a safety fault, but it can eventually bring the subdivision to a grinding halt. The brute-force solution is to recognize this possibility at every location where it could occur, and pre-plan for it with electronic workarounds. The better solution by far is to simplify the machine so that it doesn't need to know so much data so often so accurately.
True.
Engineers and marketers, as Langweische pointed out, can fall in love with their products and enable them to do everything, just in case someone might want it someday. One of my jobs right now is to figure out how many PTC features we can strip out, how many options we can turn off, and still make it work and meet the law. The last PTC system I worked on, by the time I was done, I had turned off more than 95% of the features and options originally offered by the engineers. That made me very happy!
What do we really need PTC to do - and nothing more ? (at least initially) 1) Enforce authority = limits of operation permitted for a specific train; and 2) Maximum speeds. Necessarily, it must be able to 3) Stop the train for the 1st, and/ or slow it down for the 2nd, which means it must be able to handle the braking function. That has to be scaled realisticly to avoid clogging the line with false apparent "violations". Other than that, I think that anything else is jewelry and nice-to-have but not needed "options" - like with new cars.
Paul, you pointed out earlier that the problem is the machine can break. A.C. Clarke was wrong.
No, Arthur C. Clarke was still right, if we're thinking of the same quote: "Any sufficiently advanced technology is indistinguishable from magic." He didn't say that it had to be good magic - it could equally well be bad magic. The Caiap/o Indians and their shaman in Brazil would understand that, I think.
The machines work fine, right within specs. The problem is that the machine is so complex no one ever figures out why it does anything! Have you ever figured out all the features on your cell phone? Windows computer? DVD Player? ipod? Microwave oven? How about the toaster? Nope! My daughter gave me an iPod for Christmas and I still hate the stupid thing. (I want to register a website, thisstuffsucks.com. I will list on it everything ever made or operated by Microsoft, Apple, Chrysler, AT&T, Verizon, Sprint, Comcast, Epson, H-P, Palm, Blackberry, and Kodak.) You just figure out barely enough to make it sort-of work, and when it does or doesn't do what you hope it will do, you're baffled. That is precisely what Langweische was getting at: systems that no user can ever figure out why or what it's doing, and when things go wrong, no one even knows they have gone wrong.
ROFLMAO last night when I read that! And now my wife wants to meet you, too ! She can't believe a "railroad nut" (nerd) would think that way - but she agrees completely.
A lot of Tom Clancy's plot devices in his novels revolved around faking out or spoofing computers and their sensors or users.
mudchicken will likely agree with this one: I've yet to meet a surveyor who likes the 1990's HP-48 series "pocket calculator" better than the 1980's HP-41 series it replaced - it's a "do-everything" programmable, but it's too complicated for everyday work. The astronauts used the HP-41 to go to the moon - wasn't that good enough ? Per my point above, the HP-41's plug-in pre-programmed modules for specific profession's applications were developed with input from those professions, so they were pretty intuitive and popular, unlike the HP-48. As a result of all that complexity, the HP-48 is demonstrably slower at simple, everyday tasks - like arithmetical adding and division - than the HP-41, 'cause it has to go through all that logic for even basic functions. (Actually, I'd be OK with going back to the 1970's HP-45 for a lot of work - but that's just me.)
Too bad your idea for www.thisstuffsucks.com is already taken and apparently has been since 2007 (copyright date). It's now 10 recent pages and 436 archived pages of single-spaced subjects. Though not limited to electronic gizmos - it seems to include rants about various aspects of society and life itself, for example - nevertheless a lot of it tracks your idea, so evidently there's a lot of validity and felt need there. Think up a different dot-com name and get going on your path to fame and fortune !
Langweische is my favorite author, by far. No one else gets the technical details as right, explains them as clearly, or turns a phrase so eloquently. If the last paragraph in the "Devil at 37,000 feet" article doesn't make you shiver, you might be dead from the neck up. Patrick Smith, the "Ask the Pilot" columnist and a 767 captain, said that Langweische made exactly one technical mistake in the "Devil" article, a very minor one, misnaming a control center, which might have been a spellcheck error in fact. That's as impressive a recommendation as you can get. RWM
Langweische is my favorite author, by far. No one else gets the technical details as right, explains them as clearly, or turns a phrase so eloquently. If the last paragraph in the "Devil at 37,000 feet" article doesn't make you shiver, you might be dead from the neck up. Patrick Smith, the "Ask the Pilot" columnist and a 767 captain, said that Langweische made exactly one technical mistake in the "Devil" article, a very minor one, misnaming a control center, which might have been a spellcheck error in fact. That's as impressive a recommendation as you can get.
Again, thanks for the references - I need somebody new to read. I see from his bio on the Vanity Fair website that he was formerly a professional pilot, so that undoubtedly has a lot to do with the factual accuracy, and the attention (obsession ? they're not all bad, you know) to same.
- Paul North.
edblysardYou would remember this one...ever have to wring the grease out of a Whataburger? The chicken there drips the stuff....and you can't taste the difference between the chicken and the fries...
Reminds me of a restaurant in West Quincy, MO, that featured catfish. No matter what you ordered, it tasted of catfish, especially anything that was fried. I had a greaseburger. Shoulda just had the catfish, because that's what the burger and fries tasted like!
Sounds like the Van Horn place changes it's fry oil about as often as the railroads change the oil in a locomotive.
Yeah, well, down here, if you can deep fry it, someone will eat it...
Lard is one of the major food groups, right?
edblysard Yeah, well, down here, if you can deep fry it, someone will eat it... Lard is one of the major food groups, right?
I think they have a franchise in Walsh, CO (CVRR) called Lucy's Hog Trough (real place)....
I just finished reading Langewieche's article on Somolian piracy (also in VF) and would highly recommend it.
He is an excellent writer and appears to have featured articles in VF on a regular basis. I havent read VF in several years...it got a bit nasty for my tastes, but their editorial content was always well written.
At $1 an issue, I might subscribe again. Nice cover shot for May.
MP173I just finished reading Langewieche's article on Somolian piracy (also in VF) and would highly recommend it. He is an excellent writer and appears to have featured articles in VF on a regular basis. I havent read VF in several years...it got a bit nasty for my tastes, but their editorial content was always well written. At $1 an issue, I might subscribe again. Nice cover shot for May. ed
When it's free on the website, why bother paying!
Langewische previously wrote for The Atlantic -- archives also free online -- where he specialized in ocean shipping and nuclear weapons proliferation. He authored the book "Outlaw Sea" which is based on his work at Atlantic, and is must-read to understand the ocean shipping business, and the manner in which business has learned to evade regulation and operate in an extra-legal environment, and ocean trade. While at Atlantic, James Fallows work on China has done more for me to understand that aspect of business than anything I know of.
Paul_D_North_Jrmudchicken will likely agree with this one: I've yet to meet a surveyor who likes the 1990's HP-48 series "pocket calculator" better than the 1980's HP-41 series it replaced - it's a "do-everything" programmable, but it's too complicated for everyday work. The astronauts used the HP-41 to go to the moon - wasn't that good enough ? Per my point above, the HP-41's plug-in pre-programmed modules for specific profession's applications were developed with input from those professions, so they were pretty intuitive and popular, unlike the HP-48. As a result of all that complexity, the HP-48 is demonstrably slower at simple, everyday tasks - like arithmetical adding and division - than the HP-41, 'cause it has to go through all that logic for even basic functions. (Actually, I'd be OK with going back to the 1970's HP-45 for a lot of work - but that's just me.)
Paul,
Lessee, the last manned moon mission was December 1972 (at the end of my first quarter at Bezerkeley) and I first read about the HP-35 in "Mac's Service Shop" page in the March (?) 1972 issue of Popular Electronics. Got my HP-45 in December 1973 and only stopped using it about 6 years ago after downloading a program called "grpn" (which has a resistors in parallel command that works with complex numbers - latest maintainer works for Analog Devices).
Then again, I find having to push the "talk" button on wireless phones annoying, phones are supposed to go "off-hook" when picked off the hook...
On a related note, "Robert X Cringely" had a recent article on the 30th anniversary of Three Mile Island, where he pinned most of the blame on really poor user interface design and poor operator training. One problem was that there were seven hundred warning messages being printed out before the critical one warning about dropping water levels in the reactor vessel.
Paul_D_North_Jr Then again, I find having to push the "talk" button on wireless phones annoying, phones are supposed to go "off-hook" when picked off the hook...
Reminds me of a few years ago, when our retired pastor (who was about 80 at the time) surprised everybody by finally getting a cellphone. Of course, the kids (anyone under 30, as far as I'm concerned) had to check out the phone and all it's options. "Did you know you can do this?" "Did you know you could do that?" was answered with, "No, I just need to pick it up and dial." One of them triumphantly pointed out he could program the phone recognize his voice so he wouldn't even have to do that much. He could just talk into the phone and tell it who he wanted to talk to and it would connect him-how advanced was that?
Pastor just chuckled and said, "In my day, that's how all the phones worked."
A.K. CummingsGreyhound — The political mandate has nothing to do with efficiency, and everything to do with public outcry. When people die in a preventable accident, you'll always have a government response because that's what people demand. There may be times when that goes overboard, but personally, I think it's generally a good thing. The public reaction to Upton Sinclair's "The Jungle" led the government to legislate safer food. Public reaction to Ralph Nader's "Unsafe at any speed" led the government to legislate safer cars. The list could go on ad infinitum. And generally speaking, these are good things. My opinion: The public has a stake in the rail system as passengers and as people who live beside rail lines. They deserve a seat at the table. Burlington Northern had a great deal of success experimenting with PTC back in the early 1990s. Our columnist Don Phillips was present for a demonstration of it, and was amazed at what it was able to do. I'm with you guys: It will take time and money, but the industry will find a way to implement it. Finally, as to cost, media reports indicate the cost of lawsuits alone in the Chatsworth crash could exceed $1 billion. When you calculate the efficiency of PTC, you have to include the money saved by accidents that are prevented — and I don't think there's any doubt that PTC will prevent accidents. The problem with accident prevention is that you really won't know overall when PTC has prevented a crash between a commuter train and a freight train or saved a tank car of chlorine gas from getting punctured and poisoning a community. Even if you could figure that out, you'll never know how much money was saved. However, that's not the same as saying $0 was saved. Best, Andy Cummings Associate Editor TRAINS Magazine Waukesha, Wis.
Well, If your columnist Don Phillips was present for a demonstration of it, and was amazed at what it was able to do, I guess that settles it. But then, Phillips is also aparently amazed by France so there still may be some questions here. He never saw a government power grab that he didn't like.
Seriously, the safety issue with PTC is a red herring. You can't just throw billions of dollars at a system and justify it by simply saying it will improve safety. Which is what you're doing here. If safety was an abolute goal to be pursued at the expense of everything else, trains and motor vehicles would operate at 25 MPH maximum. That would improve safety, but the cost would be prohibitive. So we drive and operate trains well above 25 MPH knowing full well that in doing so we are reducing overall costs at the expense of safety. I'm not saying safety isn't critically important. It is. What I am saying is that you can't use it to justify any expenditure, any time and any place.
PTC's projected impact on safety will be negligible. The US rail system is operated in a very safe manner. You cite $1 Billion from the Chatsworth crash as support for the need for PTC. Well, one such crash per year wouldn't pay the capital costs of a $15 billion PTC system. And fortunately, such disasters are few and far between. The cause of the Chatsworth crash is being laid on misconduct by the passenger train's engineer. Spending vast amounts of scarce resouces in reponse to very rare cases of misconduct is a waste and should not be toleraed.
Projections posted by RWM are that PTC will reduce capacity on the busiest rail routes. This should give anyone pause. You aparently do not pause. Reducing this capacity can only result in increased costs to the economy as a whole. This will divert resources from other safety projects. It has to. We can't spend the resource twice and if it is wasted on a government mandated system that results in negligible gain then other, more productive, uses of the resources must be neglected. Doing everything to achieve Utopia is not an option.
I have raised legitimate questions about the government commanded introduction of an unproved system. You resonded by citing Upton Sinclair, Ralph Nader, and Don Phillips. You did not address any of the questions. You're in love with an ideology of Utopia, just as Phillips is in love with France. Niether one works all that well.
Wel here is my 2 cents I am a qualified locomotive engineer and I work to Chicago I can operate on the CN/IC, BRC, CSX, IHB and every now and then the EJ&E I carry the cora book for the Chicago area which has the signals for all of the above railroads that I can operate on. Railroads are slowly using the same signal system but it cost money a lot of money that the railroads would rather spend on the track. Here is the way that I see the color aspect on the signals green we go, yellow we slow and red we stop problem solved.
Rodney
Rodney Beck....Here is the way that I see the color aspect on the signals green we go, yellow we slow and red we stop problem solved. Rodney
The Chatsworth crash would have been prevented. The Pere Marquette would have been a slow speed crash at worst. That signal would have sent a 15mph limit.
spokyoneRodney Beck....Here is the way that I see the color aspect on the signals green we go, yellow we slow and red we stop problem solved. Rodney Could PTC be just that simple? The signal aspect is transmitted to an approaching train. Yellow commands the engineer to reduce speed to a preset value. That value need not be the same for every signal, but would be the same for every train passing that location. Approaching a red would apply the brakes if the engineer has not already done so. An in-cab audio warning would alert the crew to a PTC intervention. The Chatsworth crash would have been prevented. The Pere Marquette would have been a slow speed crash at worst. That signal would have sent a 15mph limit.
Spokyone, what you are describing is Automatic Train Control (ATC), which has been around since the 1920s and does some of what PTC does, but badly, and worse it costs much more! Recent ATC installations have cost more than $1-2 million per mile just for the wayside equipment, which if extended over the national network that PTC will cover would cost $25 billion for the wayside plus another $4-5 billion for the locomotive hardware.
Moreover, ATC can't do a lot of things that PTC will do, except with expensive, complicated, ad hoc, inflexible, inefficient, and capacity-robbing workarounds:
I can make an ATC system do all of these things listed above, but no one will like the price tag or the harm it does to railway capacity.
ATC is state-of-the-art for 1925. It didn't work so hot then, it was terribly expensive, and little has improved. There are "modern" ATC systems out there on the market but it's sure a bad way to do things in my opinion.
We've been working on PTC for 30 years. We're not overlooking the obvious. We can debate the cost-benefit ratio, but the technical solution was figured out over a decade ago. That decision has been made, finis, as far as the Class 1 railway industry in this country is concerned.
Spokyone, what you are describing is Automatic Train Control (ATC),
Recent ATC installations have cost more than $1-2 million per mile just for the wayside equipment, which if extended over the national network that PTC will cover would cost $25 billion for the wayside plus another $4-5 billion for the locomotive hardware.
8. It cannot be installed without creating enormous problems with trade-crossing signaling because of frequency conflicts, which means several billion more to redo thousands of grade-crossing predictors.
Thank you
spokyoneI had been thinking it would be just an upgrade from CTC with bi-directional communication between the lead locomotive & the signal. The locomotive expense would be similar with PTC & ATC.
Unfortunately to install cab signals (which is what ATC is a flavor of) pretty much mandates building a whole new CTC system in many cases. Also a great deal of the PTC is going in dark or ABS territory where cab signals would require all-new signaling and PTC does not require any at all. The locomotive expense is higher with ATC than PTC because the ATC requires a lot of fussing around with the pickup shoe, and solving current and frequency isolation issues. PTC is just some boxes on a rack and some antennas on the roof. Not hard to install, and very little calibration required.
I thought grade crossing signals were completly separate & autonomous.
Unfortunately no -- not when cab signals are involved (which is what ATC is). Cab signals work using frequencies in the rail. So do grade-crossing signals. Each cab signal aspect or speed instruction requires a unique frequency broadcast down the rail. The box in the locomotive sees, say, 86 Hz, and says, "ah ha, I'm supposed to be proceeding at 30 mph and diverge at the next control point." Each grade-crossing approach circuit also requires a frequency on the rail, and they have to be unique from each other if they overlap, and on a line running at 79 mph passenger, 70 mph freight, grade crossings within 8,000-11,000 feet of each other will overlap. Also the grade-crossing signals have to span control points and insulated joints which really tangles up the frequency selection process for the cab signals. Once you start on a cab signal system, you are choosing a fixed, firm set of frequencies for the entire railway system nationwide. But grade-crossing signal frequencies are not a national standard per se but a collection of local systems designed to work effectively in their own little neighborhood, because they don't have to know wha a grade crossing on the other side of the country is doing. Very quickly frequencies are used up, and frequencies that are adjacent bleed into each other which results in things that are highly undesirable such as grade-crossing signals that do not activate or unreadable cab signal aspects which knocks the train down to restricted speed. That creates severe problems which are very costly to solve, and in some cases can't be solved at all -- which results in running all the trains at very slow speeds.
This still doesn't solve all the other problems with ATC. Using ATC instead of PTC would be like me saying, "I need to buy a car to drive to my job which is 20 miles away, but maybe I should look into walking every day instead. "
Alright, let me ask a really simple question....
Where can I read a primer on PTC? Instead of asking tons of questions about it, is there a website describing what it is, etc?
Never mind, I found plenty to read (and watch on it).
RWM, when you say ATC can't enforce restricted speed, do you mean the top allowable speed (20mph for us) by rule or the changing value of restricted speed? By changing value I mean sight distance, the less distance you can see, the slower you (should) go.
Our ATC enforces restricted speed to a preset speed limit. Exceed that limit and you get a penalty service application. It doesn't address when your speed should be under that preset limit because of limited visiblity. In that regard, I would agree with you.
Jeff
jeffhergertRWM, when you say ATC can't enforce restricted speed, do you mean the top allowable speed (20mph for us) by rule or the changing value of restricted speed? By changing value I mean sight distance, the less distance you can see, the slower you (should) go. Our ATC enforces restricted speed to a preset speed limit. Exceed that limit and you get a penalty service application. It doesn't address when your speed should be under that preset limit because of limited visiblity. In that regard, I would agree with you. Jeff
That's what I meant. You stated it better than I did.
For Ed and Spokyone, here's why that's not good enough. Suppose you have a train moving on a siding toward the end of the siding, at restricted speed (20 mph), toward a signal indicating stop. The ATC code in the rail sets a maximum of 20 mph. The train obeys that limit and no enforcement is made. But instead of stopping at the signal it continues to move past it at 20 mph, . Now the ATC provides a penalty braking application. However, by the time the train gets stopped, it's already out into the single-main track in the face of an approaching train moving at 79 mph. The safety system has just failed to prevent a collision.
There are ways you can trick ATC into stopping a train short of a signal in this case, such as putting another frequency onto the rail that tells the train to stop short, but these are the equivalent of moving the signal far enough back into the siding that an overrun has sufficient braking distance to stop before fouling the main track (at the cost of shortening the siding effective length by several thousand feet but still paying for the now useless track. However, there are other scenarios (crossovers, overspeed derailments into the path of another train), that ATC can't resolve. It's not fine-grain enough control.
Railway ManFor Ed and Spokyone, here's why that's not good enough. Suppose you have a train moving on a siding toward the end of the siding, at restricted speed (20 mph), toward a signal indicating stop. The ATC code in the rail sets a maximum of 20 mph. The train obeys that limit and no enforcement is made. But instead of stopping at the signal it continues to move past it at 20 mph, . Now the ATC provides a penalty braking application. However, by the time the train gets stopped, it's already out into the single-main track in the face of an approaching train moving at 79 mph. The safety system has just failed to prevent a collision.There are ways you can trick ATC into stopping a train short of a signal in this case, such as putting another frequency onto the rail that tells the train to stop short, but these are the equivalent of moving the signal far enough back into the siding that an overrun has sufficient braking distance to stop before fouling the main track (at the cost of shortening the siding effective length by several thousand feet but still paying for the now useless track. However, there are other scenarios (crossovers, overspeed derailments into the path of another train), that ATC can't resolve. It's not fine-grain enough control.
If I'm getting this right, the ATC equivalent of PTC in your siding example would be dividing the siding up into short blocks with decreasing restrictive speed enforcement (e.g. 20, 15, 10, 5, 2.5 ...) - difference being is that the block length would adjust to expected braking performance of the train.
I'd think it would be possible to implement the equivalent function in a modified ATC system - use and audio frequency overlay to judge the distance of the train from the end of the siding, and have the ATC signal give either a continuously variable speed limit or with small speed steps. This would require replacing all of the ATC equipment on the locomotives and at least some trackside equipment - at which point PTC makes more economic sense.
A note about technology. When continuous ATC systems were first implemented, the technology for resolving the received frequency required a relatively large spacing to reliably distinguish frequencies. It is now ridiculously easy to reliably measure frequency to a fraction of a Hz (cycle per second).
erikemIf I'm getting this right, the ATC equivalent of PTC in your siding example would be dividing the siding up into short blocks with decreasing restrictive speed enforcement (e.g. 20, 15, 10, 5, 2.5 ...) - difference being is that the block length would adjust to expected braking performance of the train.I'd think it would be possible to implement the equivalent function in a modified ATC system - use and audio frequency overlay to judge the distance of the train from the end of the siding, and have the ATC signal give either a continuously variable speed limit or with small speed steps. This would require replacing all of the ATC equipment on the locomotives and at least some trackside equipment - at which point PTC makes more economic sense.A note about technology. When continuous ATC systems were first implemented, the technology for resolving the received frequency required a relatively large spacing to reliably distinguish frequencies. It is now ridiculously easy to reliably measure frequency to a fraction of a Hz (cycle per second).
The solution you describe is a lot more frequencies than are available. I think there would be great difficulty in getting it to work with "five nines" reliability without losing a lot of train speed and track capacity. I am not educated enough to explain why in a way you'll find satisfactory. The track circuits are imperfect due to varying degrees of resistance every time the weather changes. As I recall from the last installation I worked on (a couple of months ago), we had only 12 frequencies to work with. That's with the latest, greatest ATC equipment. It still is having issues with grade-crossing predictors that don't predict due to frequency conflicts and problems with all sorts of real-world misery such as rusty rail when trains don't run for a day, squishy track subgrade that is wet one day and dry the next, and so forth, and a lot of air-brake issues.
Thanks RWM. I was thinking you meant the changing values part, but wasn't sure. Even a collision when a train is running under restricted speed conditions can be deadly.
Maybe we need another thread on PTC, but I have a couple of questions.
When approaching a Form B (work zone GCOR), how will a train be cleared up? Will they contact the foreman verbally, who will then clear them verbally and enter into the system that the train can proceed at whatever speed he prescribes thru the limits? Will the process be completely digital with the engine sending, either manually or automatically, a request for instructions and the foreman responding without actually talking to the train?
The other question is, will on-track equipment and hi-rails that may not shunt the track circuit (where there is signalled track) be equipped with GPS so that the system knows when they are out of their track authority? Most of the time people think that it is only when a train overruns a Form B that accidents can happen, but we have had instances where MOW forces left their authority. One extreme case was a track inspector getting a Track and Time on one track in two MT territory, than setting on the wrong track!
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