 Poster: A snowHead
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| SnoodlesMcFlude wrote: |
Did it. Not easy but it's doable. To be honest I found the hardest bit was finding something in my house that could replicate a chairlift |
Doesn't everyone use the other ski to stamp in the back of the binding ? Far simpler than all that pole pushing faff. It can't just be me. And that would be simple to do on a chair lift.
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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@ringingmaster, ...stamping with the rear of one ski to release the binding on the other?...that’s for pros who have free skis, or people who don’t mind shredding their bindings, surely...
...my kids have been trained NOT to do this since the edges were shredding the surface of their heel pieces...
But in extremis of course you can do it..and I sneakingly do it on rock skis when the kids aren’t looking....
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| valais2 wrote: |
@ringingmaster, ...stamping with the rear of one ski to release the binding on the other?...that’s for pros who have free skis, or people who don’t mind shredding their bindings, surely...
...my kids have been trained NOT to do this since the edges were shredding the surface of their heel pieces...
But in extremis of course you can do it..and I sneakingly do it on rock skis when the kids aren’t looking.... |
Really!!!
Always done it. Scratches the other boot a bit, but never had an actual problem causing damage.
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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| ringingmaster wrote: |
| valais2 wrote: |
@ringingmaster, ...stamping with the rear of one ski to release the binding on the other?...that’s for pros who have free skis, or people who don’t mind shredding their bindings, surely...
...my kids have been trained NOT to do this since the edges were shredding the surface of their heel pieces...
But in extremis of course you can do it..and I sneakingly do it on rock skis when the kids aren’t looking.... |
Really!!!
Always done it. Scratches the other boot a bit, but never had an actual problem causing problematic damage. |
Just a few scratches on the heel piece is no big deal
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To jettison skis, I would assume that you'd shift your skis off the foot rest, and then lift each boot above the foot rest (ski below) to use it to press on the heelside release lever (pulling the leg back up toward the body).
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Perhaps easier and quicker to jump off with your skis on. They will then release if they need to.
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@ringingmaster, @Themasterpiece, ...this is certainly one which I won’t die in a ditch for but boy you should see some of the heel pieces of ‘energetic youths’ - I know it doesn’t affect underlying function but they look dreadful...
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Im in the 'don't worry about the skis' camp. Maybe get rid of the poles but foremost, get the bar up and spot your landing area. Luckily It does seem fairly benign as a landing area, a plastic travelator thing would be nasty to land on and where they're being flung off round the back lacks cliffs, rocks, buildings etc.
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Okay, this is hindsight working but, the situation would have been improved, at least up until one of the chairs jammed, if the skiers had stayed on the lift. It was running backwards because of the weight of all the skiers on one side. If a good many had stayed on then the weight of the two sides would have balanced more and it wouldn't have travelled so fast.
I bet every lift in the world has had its anti-reverse mechanism checked now. I wonder if any have the option for it to be disabled for emergency evacuation and how many were found in that state.
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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Scary. Didn’t this happen somewhere a few years ago with major loss of life? Or did I dream it?
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And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
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You know it makes sense.
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Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
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There's been a couple of chairlift rollback incidents in the States and one in China as far as I can tell.
Last edited by Otherwise you'll just go on seeing the one name: on Sun 18-03-18 16:06; edited 1 time in total
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Poster: A snowHead
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| crosbie wrote: |
| To jettison skis, I would assume that you'd shift your skis off the foot rest, and then lift each boot above the foot rest (ski below) to use it to press on the heelside release lever (pulling the leg back up toward the body). |
I'm confident I couldn't do that - it would take a lot of leg strength. Also, if the foot rest is still down then you've still got the bar across you, which restricts your movement. People with long legs (which isn't me) don't have much space to move their legs of the bar is down.
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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On my first day of lifty training many years ago we had a session on rollbacks. First comment was "if you are ever on a lift and it rolls back, jump off before it goes around the bull wheel"!!
I'm sure the lifts I was working on had massive pins that dropped through the wheel to stop it rotating to stop this very event. It was 20 years ago however so memory is rusty. I'm amazed that this even happened, obv a serious failure somewhere!!
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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| midgetbiker wrote: |
| Gaza wrote: |
| kedsky wrote: |
| no one to switch it off ?! it is going for to long! |
I thought the same but then I began to think "is it its own momentum that is driving it?" Possible failure of a braking mechanism allowing it to run freely. It only stops when there is a number of chairs jammed under the bullwheel. |
Yeah, it's not running, it's lost power and the auto braking has failed. It's the weight of people pulling it backwards. |
This isn't really correct.
With practically any winch-driven system either moving people, or moving loads around people, the brake is, by default, in an 'on' position, and energising the system (IE sending it power) releases the brake. This ensures, in theory, that when power is cut, the brake reverts to 'on'. This is normally achieved by an electric brake installed on the drive shaft, the brake is held 'on' by some very stiff springs. On top of the brake pad(s) is a big magnet, and then just beyond that a big electromagnet. When there is no power, there is nothing opposing the springs and the brake pad(s) clamp down on the the brake disc(s) creating enough friction to stop the load. When the electromagnet is energised, it pulls the brake pad(s) away, loosening the whole system and allowing the discs to spin freely. As soon as power is isolated, the springs force the pads back down and everything stops. I cannot think of any electric driven winch system I have ever worked on, where the brakes require power to engage, it would be very dangerous in the event of power failure.
Furthermore, in most electric winch systems, the brakes are designed to hold generally at least 5 times the lifting power of the winch. In applications for lifting / moving people, it's usually 10 (often achieved just by installing a second brake unit on the shaft). And then beyond that, even if you can make it turn freely, it still applies resistance. So spinning at the speed in the photo is very unlikely to be a brake functioning correctly and simply being overloaded by momentum. It's very hard to overload the brake to the point that it turns freely.
What can happen, IME, is:
- Failure of the brake due to wear and tear on components. Self explanatory and IME, people do not strip down the machines frequently enough to inspect wear on the pads, and they either stop having friction due to being worn out (think a piece of worn sandpaper), or shatter into several pieces and disappear elsewhere in the machine.
- Incorrect spacing between the magnet and electromagnet. Screws tighten/loosen and the magnet ends up too close to the electromagnet, and not pushing down hard enough on the brakes.
- The springs get worn out and don't push hard enough.
- Wrong brake pads for the application have been installed.
- A common one in new lifts is that everything is digital. The lift has digital position encoders, weight sensors, speed control etc... which is ideal for operating. But the Emergency-Stop is also digital and talks to the computer, rather than physically cutting power. So if the computer malfunctions, the E-Stop can become worthless. Companies always claim to have factored in some kind of quadruple-redundancy or whatever they're saying this week, but generally it's crap and I've seen it a lot. The best kind of E-Stop cuts the power directly, or at least is connected directly to a relay which does.
- Or finally - and potently in ski resorts - you get moisture between the electromagnet and magnet. You run the lift for an hour without needing to stop it for any reason, and during this time, the moisture between the magnets freezes. Then you stop the lift, and the magnet doesn't push down, because the ice is holding it in place...
Not speculating which, if any of these it could be. It could be something else. These are the faults I deal with most commonly. But I am just saying it's very unlikely to have been caused by a power failure meaning the brakes didn't work, since brakes are typically very simple and any loss of power - deliberately or otherwise - is exactly what causes them to engage.
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I was sat on a very nice modern chairlift today, with loads of safety features - automatic safety bar, locking safety bar, safety bar with bits between riders legs to stop small children slipping out. All I could think was that if this goes into rollback theres no way I'm going to be able to jump!
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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| philwig wrote: |
| ... If you want to get offended about something I'd be more concerned that there weren't identifiable resort staff organising the chaos. They should have a system in place for that, but it seemed to be entirely customer organised. |
How many resort staff would you expect to be available? Many lifts have just a single operative at each end - and I would expect them to first be doing everything they could to apply any sort of braking mechanism, and second to be summoning help / rescue services. The whole incident only lasts a few minutes, so no-one is going to arrive from elsewhere.
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| Tubaski wrote: |
| I was sat on a very nice modern chairlift today, with loads of safety features - automatic safety bar, locking safety bar, safety bar with bits between riders legs to stop small children slipping out. All I could think was that if this goes into rollback theres no way I'm going to be able to jump! |
Quite! 
(They freak me out anyway. I always think the damn thing isn't going to open in time.)
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| Tubaski wrote: |
| I was sat on a very nice modern chairlift today, with loads of safety features - automatic safety bar, locking safety bar, safety bar with bits between riders legs to stop small children slipping out. All I could think was that if this goes into rollback theres no way I'm going to be able to jump! |
It was probably a high speed lift, rather than a fixed one as in the video - so you don't need to worry as it wouldnt happen as it works in a different way.
Generally lift have at least 3 operatives, one each in the control room top and bottom and one loading chairs - they rotate so when its cold they only do 20mins/hour outside. Info gleaned from different lifties in North America.
edited for typo 
Last edited by Then you can post your own questions or snow reports... on Sun 18-03-18 23:52; edited 2 times in total
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Yet another argument for not removing all drag lifts.
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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| Tubaski wrote: |
| I was sat on a very nice modern chairlift today, with loads of safety features - automatic safety bar, locking safety bar, safety bar with bits between riders legs to stop small children slipping out. All I could think was that if this goes into rollback theres no way I'm going to be able to jump! |
Honestly the majority of winch systems I work on, the new features can be convenient for the end user and can offer better cost efficiency for the operator; however I have to say for safety and reliability I like old skool mechanical things. The trouble is that most of the old systems were built so well, that many of the manufacturers went bust because they were making equipment people only bought once! So to survive, you have to sacrifice what really matters to you as a proud manufacturer, in favour of offering something to the customer that's worthy of spending money on.
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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Poor people this must have been really scary 
Imagine going along on that chair minding your own business thinking about where to ski next or what to have for lunch or something and then all of a sudden the chair lift starts whizzing backwards.
It would take you a short while to fathom out what was happening when something took you by surprise like that. I suspect the people that didn’t jump off in time had frozen from the surprise of it
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And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
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| Quote: |
m sure it's not just you, but you're missing the point. There wasn't a lot people could do other than what they were doing: in those circumstances, it doesn't much matter what bystanders do. If I was there and I needed them to do something, I'd tell them. If you were injured, you'd want the video later.
If you want to get offended about something I'd be more concerned that there weren't identifiable resort staff organising the chaos. They should have a system in place for that, but it seemed to be entirely customer organised.
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No I think you are missing the point. It's not simply a question of what you can do that is useful but what your first instinct is.
But beyond that I disagree with your assessment. There is likely to be only one staff member at the bottom and they are going to be very busy in that moment. There are people being thrown off like ragdolls who will need first aid attention and other people on the lift that could be urged to jump. The one lifty at the bottom cannot deal with that. May be I wouldn't be able to help anyone but my instinct would be to try. I think most people would feel the same. And isn't there an issue of repsect to? Would you video the aftermath of a car crash?
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| sugarmoma666 wrote: |
| crosbie wrote: |
| To jettison skis, I would assume that you'd shift your skis off the foot rest, and then lift each boot above the foot rest (ski below) to use it to press on the heelside release lever (pulling the leg back up toward the body). |
I'm confident I couldn't do that - it would take a lot of leg strength. Also, if the foot rest is still down then you've still got the bar across you, which restricts your movement. People with long legs (which isn't me) don't have much space to move their legs of the bar is down. |
I tried it at home and it takes less force than I expected when the skis are unsupported. My thinking was that you wouldn't use the footrest at all, just slide both skis off it and bring the heel piece of one ski up as you push down with the other ski. Like I say, didn't find it too tricky at all and didn't take much effort to get the binding to release. The problems would be: a)freezing in panic, b)other people panicking and trying to get their skis off, c)time.
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You know it makes sense.
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Ideally, if you have the greatest respect for human life, you have video of the events preceding a crash, the crash as it happens, and the aftermath - and the latter is better than nothing.
The number of people who take such videos for the purpose of getting their morbid rocks off later is minuscule, like the number of parents who take videos of their naked kids playing on the beach for a similar ulterior purpose.
99.99% of people are sound, even if 10% of them don't believe this.
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Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
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| dp wrote: |
| midgetbiker wrote: |
| Gaza wrote: |
| kedsky wrote: |
| no one to switch it off ?! it is going for to long! |
I thought the same but then I began to think "is it its own momentum that is driving it?" Possible failure of a braking mechanism allowing it to run freely. It only stops when there is a number of chairs jammed under the bullwheel. |
Yeah, it's not running, it's lost power and the auto braking has failed. It's the weight of people pulling it backwards. |
This isn't really correct.
With practically any winch-driven system either moving people, or moving loads around people, the brake is, by default, in an 'on' position, and energising the system (IE sending it power) releases the brake. This ensures, in theory, that when power is cut, the brake reverts to 'on'. This is normally achieved by an electric brake installed on the drive shaft, the brake is held 'on' by some very stiff springs. On top of the brake pad(s) is a big magnet, and then just beyond that a big electromagnet. When there is no power, there is nothing opposing the springs and the brake pad(s) clamp down on the the brake disc(s) creating enough friction to stop the load. When the electromagnet is energised, it pulls the brake pad(s) away, loosening the whole system and allowing the discs to spin freely. As soon as power is isolated, the springs force the pads back down and everything stops. I cannot think of any electric driven winch system I have ever worked on, where the brakes require power to engage, it would be very dangerous in the event of power failure.
Furthermore, in most electric winch systems, the brakes are designed to hold generally at least 5 times the lifting power of the winch. In applications for lifting / moving people, it's usually 10 (often achieved just by installing a second brake unit on the shaft). And then beyond that, even if you can make it turn freely, it still applies resistance. So spinning at the speed in the photo is very unlikely to be a brake functioning correctly and simply being overloaded by momentum. It's very hard to overload the brake to the point that it turns freely.
What can happen, IME, is:
- Failure of the brake due to wear and tear on components. Self explanatory and IME, people do not strip down the machines frequently enough to inspect wear on the pads, and they either stop having friction due to being worn out (think a piece of worn sandpaper), or shatter into several pieces and disappear elsewhere in the machine.
- Incorrect spacing between the magnet and electromagnet. Screws tighten/loosen and the magnet ends up too close to the electromagnet, and not pushing down hard enough on the brakes.
- The springs get worn out and don't push hard enough.
- Wrong brake pads for the application have been installed.
- A common one in new lifts is that everything is digital. The lift has digital position encoders, weight sensors, speed control etc... which is ideal for operating. But the Emergency-Stop is also digital and talks to the computer, rather than physically cutting power. So if the computer malfunctions, the E-Stop can become worthless. Companies always claim to have factored in some kind of quadruple-redundancy or whatever they're saying this week, but generally it's crap and I've seen it a lot. The best kind of E-Stop cuts the power directly, or at least is connected directly to a relay which does.
- Or finally - and potently in ski resorts - you get moisture between the electromagnet and magnet. You run the lift for an hour without needing to stop it for any reason, and during this time, the moisture between the magnets freezes. Then you stop the lift, and the magnet doesn't push down, because the ice is holding it in place...
Not speculating which, if any of these it could be. It could be something else. These are the faults I deal with most commonly. But I am just saying it's very unlikely to have been caused by a power failure meaning the brakes didn't work, since brakes are typically very simple and any loss of power - deliberately or otherwise - is exactly what causes them to engage. |
No - what I meant was 'it's lost power' (so it's no longer being driven up) AND 'the auto braking has failed' (so it's coming back down). I didn't mean to imply the auto braking had failed due to the lack of power (that would hardly be 'auto'), though I can see how it could be read that way.
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Poster: A snowHead
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In the emergency services, first on scene is told to report back, to not get involved in assisting etc. Their value is in reporting the issue, likely casualty numbers, other services required and such. The lifty, as stated, is probably trying to multi-task calling for help and trying to do something about the out of control lift.
First on scene at Kings Cross fire went in; this has been noted to not be the best way to deal with a potential major inc.
Criticism can be levelled by members of the public when, to their perception, an emergency services worker is stood back, seemingly not doing anything to help, when in fact they are keeping their cool, being professional and doing exactly as trained, to get the most effective resources to the location as quickly as possible. Lifty could have been doing a sterling job.
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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The videos are terrifying, I had no idea that could even happen. I hope I'd be brave enough to jump off in time.
A few people in the clips who were thrown off or into the mangled chairs look as though they were quite badly injured, I'm amazed no-one died. The snowboarder in yellow had a close call as well, he just ducked in time.
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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You need to Login to know who's really who.
You need to Login to know who's really who.
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@Mike Pow, +1, though instead of Gudauri I would recommend Mestia and nearby Tetnuldi which have a lot more to offer both on and off slope.
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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| hd wrote: |
| @Mike Pow, +1, though instead of Gudauri I would recommend Mestia and nearby Tetnuldi which have a lot more to offer both on and off slope. |
Combine them. That's what we're going to do on our next trip.
With a couple of days in Tbilisi too
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@Mike Pow, indeed, but if/when I go again tbh I would skip Gudauri altogether for the reasons explained in my TR plus complex transit to other areas, and visit one of the other Georgian resorts instead then Mestia/Tetnuldi again which are amazing.
I understand though that you were a lot luckier with the snow in Gudauri than us.
And yes Tbilisi is well worth a couple of days.
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| midgetbiker wrote: |
No - what I meant was 'it's lost power' (so it's no longer being driven up) AND 'the auto braking has failed' (so it's coming back down). I didn't mean to imply the auto braking had failed due to the lack of power (that would hardly be 'auto'), though I can see how it could be read that way. |
I see, so you're saying that there is electricity going to the drive (hence the break is off because it's getting power), but that isn't driving the lift forwards.
That would make sense. And like I said in my other post, if operating on a new fancy E-Stop which doesn't literally sever the power supply to the machinery, possible that when the lifty hit the E-Stop it didn't cut the power completely, engaging the brake.
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| dp wrote: |
| midgetbiker wrote: |
No - what I meant was 'it's lost power' (so it's no longer being driven up) AND 'the auto braking has failed' (so it's coming back down). I didn't mean to imply the auto braking had failed due to the lack of power (that would hardly be 'auto'), though I can see how it could be read that way. |
I see, so you're saying that there is electricity going to the drive (hence the break is off because it's getting power), but that isn't driving the lift forwards.
That would make sense. And like I said in my other post, if operating on a new fancy E-Stop which doesn't literally sever the power supply to the machinery, possible that when the lifty hit the E-Stop it didn't cut the power completely, engaging the brake. |
You may well be right, but I'm afraid I'm not even being that clever. All I was saying were two rather simplistic and in my mind unconnected (though possibly connected) statements:
Power to drive the lift up has been lost (either electrical power do no drive, or loss of mechanical drive despite electrical power)
and seperately
The auto brake has failed (for reasons I have no expertise to comment on)
It's not that I disagree with anything you've said, I've just plain got no idea. I'm just pointing out that I didn't mean to imply the auto brake needed power to operate (quite the opposite infact, even I know that).
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You'll get to see more forums and be part of the best ski club on the net.
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OK... all I mean is that it is unusual to have a situation where both the brake is disengaged AND the drive isn't turning because that means you have power to one and not the other and in most industrial machines they sit on the same circuit so you can't end up in a situation where the brake is disengaged but the motor is not powered.
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I have taken a look at all the press coverage and so far the sum injuries seem 11, with 5 remaining in hospital with ‘minor injuries’. This doesn’t quite stack up. The forces involved were very significant; equal to a lowish-speed car accident I would suggest, with some people impacting on hard objects and surfaces without the benefit of any restraints or airbags. In car-pedestrian impacts with this much energy, injuries are frequently fatal or serious. Two or three people in the video are unconscious, and the single sitting person (female?) in red/orange who gets hurled into the tangle of chairs experiences a very high-energy impact. It’s the 20th March, and the accident happened on the 16th, and 5 remain in hospital. I suspect that a few were seriously injured, unless there is information to the contrary. Does anyone have better information than the scant reporting on the web?
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FAQ
