Paul of CovingtonInstead of the engineers leaning on their horns, I wonder if a series of short blasts (or double toots as used in work areas) by both of them would have made it more apparent that there were two trains.
I suggested this back at the beginning of this thread, with the added idea that emergency horn use should be formalized and 'trained'. In my opinion the emergency signal used on the NYC subways -- which is alternating long and short blasts with a space in between -- is hard to beat as the default choice.
As it happens, my daughter and I were almost in a crossing-related wreck a couple of months ago, when she had just gotten her license and I was helping her 'hone her skills'. Some nitwit had pushed onto a crossing (we never saw her) and I only noticed the continuous horn-blowing of the approaching train after a few seconds... it rapidly becomes tolerated for psychophysical reasons charlie hebdo can describe with some assurance. It took me several seconds to figure out what the heck was going on ... and in fact it took the 'bang' of the collision to tell me what it was. I told her to abort the left turn she was starting to make, and get out of the intersection and away from the crossing ASAP.
Which was a good thing: our moron floored it after getting hit, and went precisely across where we had been at high speed, winding up deep in someone's door on the other side.
So I have firsthand experience on both the need for and the value of a defined convention for emergency horn use that cannot blend into perceived ambient noise. The 'two little repeated toots' in work zones is just a note that an ostensibly-protected train is passing, more a heads-up than actual warning. What is needed is an actual imminent-danger code, specifically including quiet gaps, coupled with training that says in part 'look around you immediately if you hear it, and keep yourself ready to react appropriately'.
I might add that it should be possible to incorporate this into locomotive 'automatic horns', perhaps with its own dedicated control which would also flash the ditch lights in a comparable pattern. Once that 'logic' has been incorporated into the bus network, it might be useful to use it as an analogue of the red Mars lights on some midwestern steam, and activate it upon emergency-brake activation the same way 'autohorn' can be used approaching grade crossings. (This also resolves the moral question whether you go to emergency immediately when you see a life-threatening situation, I think -- now all the due-care actions with horn and lights happen automagically just by plugging the air, and any UDE is promptly communicated to any approaching passing train -- remember how useful this would have been to at least one oil-train BOOM accident)
Paul of Covington Instead of the engineers leaning on their horns, I wonder if a series of short blasts (or double toots as used in work areas) by both of them would have made it more apparent that there were two trains.
Instead of the engineers leaning on their horns, I wonder if a series of short blasts (or double toots as used in work areas) by both of them would have made it more apparent that there were two trains.
Johnny
Part of the point here is that short blasts -- while preferable to 'leaning on the horn button' -- are not quite the right answer either.
What is needed is (1) a definitive signal that means 'stop what you think you are doing and look around for danger', which (2) is discontinuous 'enough' that you will likely hear other sources sounding the same alert from different locations or directions that 'you should know'. You could do this with multiple short blasts sounded in intermittent groups, a bit like Morse "H" sounded with a lazy hand, but that's not immediately distinctive. I'd have suggested Morse "V" as I have in the distant past, as it has the 'take notice' blasts followed by a long one for "watch it!", but the NYC alert with gaps is shorter and, I think, better.
Overmod Part of the point here is that short blasts -- while preferable to 'leaning on the horn button' -- are not quite the right answer either. What is needed is (1) a definitive signal that means 'stop what you think you are doing and look around for danger', which (2) is discontinuous 'enough' that you will likely hear other sources sounding the same alert from different locations or directions that 'you should know'. You could do this with multiple short blasts sounded in intermittent groups, a bit like Morse "H" sounded with a lazy hand, but that's not immediately distinctive. I'd have suggested Morse "V" as I have in the distant past, as it has the 'take notice' blasts followed by a long one for "watch it!", but the NYC alert with gaps is shorter and, I think, better.
Good points. Something distinctive, based on research, not just tradition, and it should be assigned an automated 'hot' button in each cab.
I agree with these points about making the horn signal more distinctive. Not only would it sound different and could be specialized for extreme danger alert, but it also could offer the advantage of not being able to be easily duplicated in perfect time with a second train sounding the same warning.
That is the effect of two engineers "laying on the horn" at the same time and making it sound like one train. Although, it is easy to understand why engineers would do that because time is running out, and they feel a need to get as much horn blowing done as possible in order to maximize the warning.
Then there could also be instructions for engineers to more carefully "read" the situation to determine whether two independent train warnings are better than one, or whether they may make the two warnings seem like one and cause a deception.
There is also the light issue as the ones from behind were washed out from the one in front.
Maybe tie that hot button to create a strobe effect with the ditch lights ..
It is interesting and perhaps telling that railroad tradition has led to using a series short toots or blasts to indicate the maximum warning to people on the track, rather than long and insistent sounding warning sounds. They must feel that the blank spaces between the sounds cause the sounds to have more punch. It is a principle of music, or even graphic art. Less is more. The most important parts are what you leave out.
Someone like Dave Klepper, a highly trained acoustic engineer, would likely know best, but changes in pitch would possibly also be more noticeable?
rdamonMaybe tie that hot button to create a strobe effect with the ditch lights ..
Read my post at 7:39. Yes, there should be a button that triggers 'autohorn' with patterned lights to accompany; yes, it should also trigger when the brakes are placed in emergency; yes, this 'tips the balance' over into using emergency position as a 'first response' when anything that can respond is seen fouling the track.
Be interesting to see whether there are sources that could partially or wholly underwrite the cost of this as a 'voluntary mandate' from AAR. I suspect most of the programming and implementation on modern locomotives would be comparatively minor, depending on how the software and hardware currently implement 'autohorn'.
Incidentally, based on critical-systems research in ITU group R10, you do NOT want to strobe the lights, especially if they are pseudowhite LEDs on 'bright'. All this does is blind people and ruin any dark adaptation they might need to avoid hazards as they react at night or under conditions of poor visibility or bad weather. What is preferable is to cycle the lights smoothly between bright and dim, or even normal and dim -- human peripheral vision is especially sensitive to motion, and will pick up the difference in brightness remarkably well. It might be possible to 'strobe' on bright for a very brief pulse at 'peak' light intensity in the smooth cycle, as one of the criteria that indicates 'danger' to the trained, and you will note that this is now well-differentiated from the effect of 'flashing ditch lights'.
(Amusingly enough, there are potential legal issues to using brief flashes of LED light for this purpose; most secondary cameras are CCD with a fairly long interval between short capture periods -- this is why so many early pictures of the Siemens ACS-64s looked so strange; the LED multiplexing drive being out of phase with the effective capture periods so the lights often looked dim or 'out' when actually bright. Lawyers will doubtless use camera footage to establish 'the safety lights weren't working' when we all know better...)
charlie hebdo Someone like Dave Klepper, a highly trained acoustic engineer, would likely know best, but changes in pitch would possibly also be more noticeable?
Yes, I do think that something with a more distinct sound including pitch changes would be a good idea and use it as a special "red button" for emergencies, as you mentioned. Consider all the specialized audio warnings of police cars for instance.
Overmod rdamon Maybe tie that hot button to create a strobe effect with the ditch lights .. Read my post at 7:39. Yes, there should be a button that triggers 'autohorn' with patterned lights to accompany; yes, it should also trigger when the brakes are placed in emergency; yes, this 'tips the balance' over into using emergency position as a 'first response' when anything that can respond is seen fouling the track. Be interesting to see whether there are sources that could partially or wholly underwrite the cost of this as a 'voluntary mandate' from AAR. I suspect most of the programming and implementation on modern locomotives would be comparatively minor, depending on how the software and hardware currently implement 'autohorn'. Incidentally, based on critical-systems research in ITU group R10, you do NOT want to strobe the lights, especially if they are pseudowhite LEDs on 'bright'. All this does is blind people and ruin any dark adaptation they might need to avoid hazards as they react at night or under conditions of poor visibility or bad weather. What is preferable is to cycle the lights smoothly between bright and dim, or even normal and dim -- human peripheral vision is especially sensitive to motion, and will pick up the difference in brightness remarkably well. It might be possible to 'strobe' on bright for a very brief pulse at 'peak' light intensity in the smooth cycle, as one of the criteria that indicates 'danger' to the trained, and you will note that this is now well-differentiated from the effect of 'flashing ditch lights'. (Amusingly enough, there are potential legal issues to using brief flashes of LED light for this purpose; most secondary cameras are CCD with a fairly long interval between short capture periods -- this is why so many early pictures of the Siemens ACS-64s looked so strange; the LED multiplexing drive being out of phase with the effective capture periods so the lights often looked dim or 'out' when actually bright. Lawyers will doubtless use camera footage to establish 'the safety lights weren't working' when we all know better...)
rdamon Maybe tie that hot button to create a strobe effect with the ditch lights ..
Yes. We are programmed to notice sensory input changes more than constants. Also, strobe flashing can be disorienting and in some people (not only those diagnosed with a seizure disorder) could precipitate a seizure.
Overmod Some nitwit had pushed onto a crossing (we never saw her) and I only noticed the continuous horn-blowing of the approaching train after a few seconds...
Interesting. So there again is a case of using continuous horn blast as opposed to the correct signal of a succession of short blasts.
A continous horn blast strikes me as an expression of extreme impatience with the driver. The industry carries a lot of frustration for crossing violators, and the continous blast seems to be an expression of that frustration by meaning to say "Don't you get it, idiot?" It almost seems like a form of vengeance rather than warning.
charlie hebdoSomeone like Dave Klepper, a highly trained acoustic engineer, would likely know best, but changes in pitch would possibly also be more noticeable?
Speaking from a different perspective, I believe there are a number of studies dating well back before WWII that establish changes in pitch as being valuable in emergency alerts -- at least one of them (I regret I've forgotten the citations) being a basis for my understanding that monotone pitches -- even in attractive-sounding or, as KCS and later EMD thought effective, dissonant chords) rapidly become processed as part of ambient noise. Mr. Klepper will have links to at least some of this material.
Something else Mr. Klepper can certainly tell us with distinctive competence is the best notes to choose, and the best patterns of tonality to consider, to get the most distinctive signal that cuts through ambient noise even at long range.
Something that immediately jumps out at me is the possibility of modulating a block to some of the bells in a chime horn like a K5LA, perhaps with individual solenoid control easily 'retrofitted' to existing horns. This would allow both the perceived chord and overall timbre to be varied, in patterns that could be more complex than just a 'hee-haw'.
Someone who is familiar with the Union Pacific experiments with Federal Signal-type sirens on locomotives can tell whether they tried modulating the things in some of the ways ambulances/police vehicles do their electronic sirens. I should point out in passing that I think it's important to keep railroad alert signals DISTINCTLY different from any possible confusion with other types of alert, including weather horns as well as typical first-response sounds, so just putting a good loud PA with an OTS si-reen chip in it on a locomotive is not the right answer.
At least one of our resident Canadians probably knows how they got a locomotive chime horn to blow the first notes of 'O Canada' -- that might be a workable solution.
But remember, in this Ivy City accident the problem was not a failure to hear or understand the horn signal. It was that the victims mistakenly perceived two train horn signals as one signal.
So the point would be to make a horn signal that could be differentiated from that of another train being sounded at the same time.
charlie hebdoYes. We are programmed to notice sensory input changes more than constants. Also, strobe flashing can be disorienting and in some people (not only those diagnosed with a seizure disorder) could precipitate a seizure.
There was something else, amusing at the time but I think of some relevance here, that came out of the R10 research -- it had to do with the standard ASCII character rendering codes on IBM terminals of the ancient period around the time many nuclear power plant instrumentation suites were being built with them. (Those familiar with 'tubes' will recognize this in better context).
IBM had a 'blink' attribute, which by intention worked with bright highlighting to 'convey a need for attention'. The problem I had with this was that it was only modal 'on-off' blinking, and the transition from full off to full bright was distracting when you actually had first to read the text critically and then think about how to respond to it.
We did very brief testing to confirm that the rather obvious solution -- keeping normal-density display 'on' during the bright 'blink off' interval -- worked better. (Dimming text cyclically from normal also worked nicely). Out of this, of course, it's possible to develop fancy cycling of brightness and color, etc. etc. etc. to convey different levels of default or coded meaning.
EuclidSo the point would be to make a horn signal that could be differentiated from that of another train being sounded at the same time.
This brings up another difficulty that all of us have probably experienced at one time or another - the analogue of phase-coherent multipath interference.
Many's the time that I distinctly hear a horn coming from the direction of a large properly-aligned wall, or hear it much more clearly from the 'false' direction than from where the train actually is. At Ivy City the conductors had a long train of sound-reflective cars to their left, and any 'directional' characteristic of trains physically in front of or behind them might easily have been confused by reflection from that -- let alone any other potential things in the local environment.
I'm not sure anything but an extremely directional horn that could be steered right onto a 'subject' would cut through this reliably. When I was much younger, I in fact advocated just such a thing (with the addition of a microphone that could be used to yell at kids wearing then-new Walkman headphones ... dates the era, doesn't it?) complete with some kind of designator that would allow easy and quick steering of the speaker horn onto the 'target' (also dates the era that this was a relatively new approach.) Problem is that such a thing would become just like the SP experiments in warning lights: perhaps few lives actually saved, but a lot of FRA compliance considerations and a guarantee of strict scrutiny should anyone actually be hurt or killed by a locomotive with the system installed.
Change in pitch to catch attention? How about a siren, which does have changes? I am trying to remember what locomotive(s) had a siren.
Overmod Euclid So the point would be to make a horn signal that could be differentiated from that of another train being sounded at the same time. This brings up another difficulty that all of us have probably experienced at one time or another - the analogue of phase-coherent multipath interference. Many's the time that I distinctly hear a horn coming from the direction of a large properly-aligned wall, or hear it much more clearly from the 'false' direction than from where the train actually is. At Ivy City the conductors had a long train of sound-reflective cars to their left, and any 'directional' characteristic of trains physically in front of or behind them might easily have been confused by reflection from that -- let alone any other potential things in the local environment. I'm not sure anything but an extremely directional horn that could be steered right onto a 'subject' would cut through this reliably. When I was much younger, I in fact advocated just such a thing (with the addition of a microphone that could be used to yell at kids wearing then-new Walkman headphones ... dates the era, doesn't it?) complete with some kind of designator that would allow easy and quick steering of the speaker horn onto the 'target' (also dates the era that this was a relatively new approach.) Problem is that such a thing would become just like the SP experiments in warning lights: perhaps few lives actually saved, but a lot of FRA compliance considerations and a guarantee of strict scrutiny should anyone actually be hurt or killed by a locomotive with the system installed.
Euclid So the point would be to make a horn signal that could be differentiated from that of another train being sounded at the same time.
Not to mention that the Ivy City area where this happened is a man made canyon of buildings with the railroads and highways in the valley in between.
Never too old to have a happy childhood!
Police/Fire/EMS have multi-colored lights and high/low pitched sirens.
Perhaps a elecronic bell could serve more functions.
The electric carts at ATL airport recently installed a high mounted blue LED light that lights up the path infront of people they are approching from behind.
DeggestyI am trying to remember what locomotive(s) had a siren.
One of the things tried in the 1930s during the 'first wave' of high-speed operation was sirens on locomotives and 'power cars', likely in part because of the similarity to emergency equipment. (I'll be cynical and speculate at least part of this would involve an intentional similarity to contemporary police sirens...)
I have never seen a consensus other than that these were unsuccessful and discontinued in a comparatively brief time, similar to upward-facing headlights and rotating spotlight beams.
As mentioned, Union Pacific tried some large sirens (you can easily find pictures of Centennials equipped with them - a large thin-rectangular mouth visible just over the cab). I believe Don Strack covers some of the experiment. Again this was not 'proceeded with' after testing.
I have frequently thought that steam-locomotive 'quilling' gives many of the advantages of 'pitch' or timbre changing as a means of reinforcing attention. There have been occasional efforts to duplicate the effect (or the general physics) including unless I'm mistaken on the Hancock air-whistle style (which it seems to me could relatively easily be fitted with a driving coil for adding electronically-amplified signals or e-bell). It is my understanding that you don't get much if any good effect by modulating the air pressure to diaphragms of a normal type of chime horn, but it does seem possible to vary the relative loudness of bells, within some range, since I believe many modern horns offer 'loudness control' by regulating the admitted air pressure and what works for the horn as a whole would work on individual bells.
Tangential, but related is the current practice of locomotive horns. Could their field be narrowed to be more unidirectional? Is there research to support the db level used, which seems much louder than in the late days of steam and first and second generation diesel? Is dash dash dot dash the best way to signal level crossings or is it just a tradition not used in many other countries?
charlie hebdoTangential, but related is the current practice of locomotive horns. Could their field be narrowed to be more unidirectional? Is there research to support the db level used, which seems much louder than in the late days of steam and first and second generation diesel? Is dash dash dot dash the best way to signal level crossings or is it just a tradition not used in many other countries?
Take your pick
https://www.youtube.com/watch?v=mMkJc3xsYC4
There two different problems:
The problem that caused the Ivy City accident.
The problem of warnings unable to grab attention.
It is easy to solve #2 by just throwing out a bigger warning, but that would not have prevented #1.
No, the problem of #1 is much more finessed. Nobody had trouble hearing the warning. If #66 had not blown its horn, the two conductors would likely have heard the horn of #175 and realized it was coming up behind them, and there would have been no accident. If #66 was not approaching, there would have been no accident.
Where is Alonzo Billups when we need him :)
BaltACD charlie hebdo Tangential, but related is the current practice of locomotive horns. Could their field be narrowed to be more unidirectional? Is there research to support the db level used, which seems much louder than in the late days of steam and first and second generation diesel? Is dash dash dot dash the best way to signal level crossings or is it just a tradition not used in many other countries? Take your pick https://www.youtube.com/watch?v=mMkJc3xsYC4
charlie hebdo Tangential, but related is the current practice of locomotive horns. Could their field be narrowed to be more unidirectional? Is there research to support the db level used, which seems much louder than in the late days of steam and first and second generation diesel? Is dash dash dot dash the best way to signal level crossings or is it just a tradition not used in many other countries?
Based on research, if any exists.
charlie hebdo BaltACD charlie hebdo Tangential, but related is the current practice of locomotive horns. Could their field be narrowed to be more unidirectional? Is there research to support the db level used, which seems much louder than in the late days of steam and first and second generation diesel? Is dash dash dot dash the best way to signal level crossings or is it just a tradition not used in many other countries? Take your pick https://www.youtube.com/watch?v=mMkJc3xsYC4 Based on research, if any exists.
Based on existance - everyone forms their own 'science' where warnings are concerned.
To get this steered back to charlie's reasonably verifiable sources: there is some work on maximum alarm volume (some in nuclear power, some in aircraft warning systems) and some about relative loudness and prioritization when there are multiple alarms that have to be discriminated in realtime (as in a damaged aircraft or recovery from severe CAT).
There was at least a discussion of effective measured SPL at grade crossings in the research that led up to wayside horns, and some more in how to design and orient the waysides for 'best' effect.
GM had to have done some careful experimentation into alarm sounds to come up with the coolant alarm in the last-generation heavy Eldorados in the '70s; I have experienced the alarms in the control room at TMI 2 and that little GM device under the dashboard is more alarming! If starting to research an electronically-generated critical-alert tone I'd start with that.
Charlie - do you have thoughts on a correct methodology to design alert sounds for the particular situation posed by the Ivy City tragedy?
Since I have reading rights at the UofM cognitive science library I will check to see what is recent on the science of critical alert systems. I can't guarantee anything but it's a start.
The first place I actually heard 132-dB horns fired in anger, and intentional dissonance a la the mid-70s revision of the Energency Broadcast System alert (before the modem warble tones were included) was on KCS through Bossier City in the late 1980s. Those trains were miles away, moving at a right angle, but sounded only a block or so over; it is inconceivable that anyone at a grade crossing with AC on and music playing wouldn't hear it. Only recently has this 'design practice' come back into conscious use, on late production EMDs. There may be some Progress documentation about why they build and tune their horns that way.
Overmod To get this steered back to charlie's reasonably verifiable sources: there is some work on maximum alarm volume (some in nuclear power, some in aircraft warning systems) and some about relative loudness and prioritization when there are multiple alarms that have to be discriminated in realtime (as in a damaged aircraft or recovery from severe CAT). There was at least a discussion of effective measured SPL at grade crossings in the research that led up to wayside horns, and some more in how to design and orient the waysides for 'best' effect. GM had to have done some careful experimentation into alarm sounds to come up with the coolant alarm in the last-generation heavy Eldorados in the '70s; I have experienced the alarms in the control room at TMI 2 and that little GM device under the dashboard is more alarming! If starting to research an electronically-generated critical-alert tone I'd start with that. Charlie - do you have thoughts on a correct methodology to design alert sounds for the particular situation posed by the Ivy City tragedy?
Sorry but that's not in my wheelhouse, to use a moth-eaten phrase.
Perhaps those old Chrysler air raid sirens from the early days of the cold war might get some attention?
Dedicated Hemi engine to power them.
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