Sugarloaf Chair Accident

[Mister Moose]

At 10:30AM, one lift mechanic arrived at Tower 8 and another arrived at the bottom terminal of Spillway East. Working in tandem, the mechanic at the bottom terminal of Spillway East communicated with the mechanic on Tower 8 while he made an adjustment to the sheave train per Sugarloaf’s operating and maintenance procedures. The lift was slowly started to enable the cable to settle back into the correct location on the sheaves.

The realignment effort was unsuccessful. The mechanics repeated the procedure, again unsuccessfully. The mechanic on Tower 8 determined that it would be inappropriate to run the chair at normal operating speed and the lift should be closed.

For me, this raises more questions than it answers.



Thinking about what a sheave train wheel looks like in cross section, it doesn't make sense that the whole assembly would have the cable not lie in the center groove. It would not be stable outside of the groove. (Wouldn't the cable be able to bend 1/4 inch or so laterallly over the several hundred feet between towers?) The only way this makes any sense is if the sheave train was not in alignment with itself, and the cable was centered in most of the wheels, but not in a few of the wheels. If that was the case, I really don't understand how safety procedures for the lift would ever be allowed to restart with such a misaligned sheave train. And if somehow the entire sheave train had the cable out of the groove, I'd think you'd be even less safe restarting the lift.

I also don't understand the wind was a factor comment. My understanding of wind issues is that chairs would start to bang on the towers from too much swinging. I don't see how a deropement could occur prior to a chair actually catching on a tower. If that could even happen. Can anyone explain how high winds would derope a chairlift?

[Clutch]

At 10:30AM, one lift mechanic arrived at Tower 8 and another arrived at the bottom terminal of Spillway East. Working in tandem, the mechanic at the bottom terminal of Spillway East communicated with the mechanic on Tower 8 while he made an adjustment to the sheave train per Sugarloaf’s operating and maintenance procedures. The lift was slowly started to enable the cable to settle back into the correct location on the sheaves.

The realignment effort was unsuccessful. The mechanics repeated the procedure, again unsuccessfully. The mechanic on Tower 8 determined that it would be inappropriate to run the chair at normal operating speed and the lift should be closed.

For me, this raises more questions than it answers.



Thinking about what a sheave train wheel looks like in cross section, it doesn't make sense that the whole assembly would have the cable not lie in the center groove. It would not be stable outside of the groove. (Wouldn't the cable be able to bend 1/4 inch or so laterallly over the several hundred feet between towers?) The only way this makes any sense is if the sheave train was not in alignment with itself, and the cable was centered in most of the wheels, but not in a few of the wheels. If that was the case, I really don't understand how safety procedures for the lift would ever be allowed to restart with such a misaligned sheave train. And if somehow the entire sheave train had the cable out of the groove, I'd think you'd be even less safe restarting the lift.

I also don't understand the wind was a factor comment. My understanding of wind issues is that chairs would start to bang on the towers from too much swinging. I don't see how a deropement could occur prior to a chair actually catching on a tower. If that could even happen. Can anyone explain how high winds would derope a chairlift?

The misaligned wheel in the sheave train could have been caused by the wind blowing a chair into the lift tower.

Other than that, I think you guys are on to something. Everyone should avoid the bear chair and snowden chairs on windy days that follow powder days of more than 8 inches.

[ski]

Other than that, I think you guys are on to something. Everyone should avoid the bear chair and snowden chairs on windy days that follow powder days of more than 8 inches.

In fact, I think everyone should just stay home anytime there is more than 8" . . . safety first !!

[Big Bob]

Mister Moose, the sheeve trains on this particular lift are hanging sheave trains, which is different in cross section than the one you have picture.Yours looks like the current Poma design as used on the Skye Peak Express. See Rocket21 post at 4:05

http://www.snowjournal.com/page.php?cid=topic17218

[Big Bob]

Add me into the disagrees with JG on this one camp.

When every national media outlet in the nation is using your facebook page for leads of any sort - you have the right (and should) do a few things to reduce the amount of crapola for a period of time that appears front and center. It's still there - just in the "others" filter.

Prior to them making that change, the most useful and informative stuff was constantly being buried by randoms shouting random crap. For a period of time - they can and should make it easy for all to access SL information on the SL fb page. If people or mainstream media want other junk, they can go anywhere else to get it. It's not stifling info - it's using the tools in the toolbox.

Didn't take long for "other junk" to appear!

http://www.facebook.com/pages/Dear-Boyn ... 805?v=wall

[Mister Moose]

Mister Moose, the sheeve trains on this particular lift are hanging sheave trains, which is different in cross section than the one you have picture.Yours looks like the current Poma design as used on the Skye Peak Express. See Rocket21 post at 4:05

You mean this photo?



I see your point on the support design of the entire sheave train, but the sheave cross section itself appears to be the same basic shape. The fact that it is hanging doesn't change the questions I asked.

[Stormchaser]

Mister Moose, the sheeve trains on this particular lift are hanging sheave trains, which is different in cross section than the one you have picture.Yours looks like the current Poma design as used on the Skye Peak Express. See Rocket21 post at 4:05

You mean this photo?



I see your point on the support design of the entire sheave train, but the sheave cross section itself appears to be the same basic shape. The fact that it is hanging doesn't change the questions I asked.

Could chairs swinging in the wind tug the cable towards the outside of the sheave train causing the first and last wheels in the train not to be in alignment with the cable? i.e. the two inner wheels have the cable correctly seated, but the two outer wheels are improperly seated cuz the cable moved (not the sheaves correctly).

[Mister Moose]

I see your point on the support design of the entire sheave train, but the sheave cross section itself appears to be the same basic shape. The fact that it is hanging doesn't change the questions I asked.

Could chairs swinging in the wind tug the cable towards the outside of the sheave train causing the first and last wheels in the train not to be in alignment with the cable? i.e. the two inner wheels have the cable correctly seated, but the two outer wheels are improperly seated cuz the cable moved (not the sheaves correctly).

Interesting thought. Probably under certain conditions for the entry sheave, wouldn't really matter for the exit sheave. My instinct is that a sudden high gust would tend to create a momentary small lateral cable tug, but the inter tower distance is fairly short for the tension, not a lot of catenary there. The change in entry angle would be miniscule. It also would be a transient, one half cycle later the cable would tug in the opposite direction. It would be an oscillating, not linear motion. Our collective field experience is that the chairs swing more than the cable itself does, right? Something to start watching for on the longer stretches on a (cross)windy day - like the saggy part of the Glades triple just above GN.

[JerseyGuy]

Does anybody besides JerseyWhiner give a rat's ass about whether Sugarloaf locked down their facebook page for 4 hours after a double chair failure where people got injured?

do you actually think that jersey boy is a skier? do you actually think he has ever actually skied... do you actually think he has time to ski... he is a full time Kzone poster who does a little side work as Keith Olberman's personal butt boy.... also known as a full time LOSER.... no one with any common sense takes him serious....

Telly's still alive? Well, I'll be...

[Big Bob]

Mister Moose, the sheeve trains on this particular lift are hanging sheave trains, which is different in cross section than the one you have picture.Yours looks like the current Poma design as used on the Skye Peak Express. See Rocket21 post at 4:05

You mean this photo?



I see your point on the support design of the entire sheave train, but the sheave cross section itself appears to be the same basic shape. The fact that it is hanging doesn't change the questions I asked.

Could chairs swinging in the wind tug the cable towards the outside of the sheave train causing the first and last wheels in the train not to be in alignment with the cable? i.e. the two inner wheels have the cable correctly seated, but the two outer wheels are improperly seated cuz the cable moved (not the sheaves correctly).

I would think it could. It doesn't appear that the hanger rod could take a lot of twisting considering the distance from the outer sheave wheel and the amount of force that could be exerted by the wind. This has been modified by the installation of the turnbuckle. I would think this would make the situation worse since the assembly could not swing like a pendulum.

[DrJeff]

I see your point on the support design of the entire sheave train, but the sheave cross section itself appears to be the same basic shape. The fact that it is hanging doesn't change the questions I asked.

Could chairs swinging in the wind tug the cable towards the outside of the sheave train causing the first and last wheels in the train not to be in alignment with the cable? i.e. the two inner wheels have the cable correctly seated, but the two outer wheels are improperly seated cuz the cable moved (not the sheaves correctly).

Interesting thought. Probably under certain conditions for the entry sheave, wouldn't really matter for the exit sheave. My instinct is that a sudden high gust would tend to create a momentary small lateral cable tug, but the inter tower distance is fairly short for the tension, not a lot of catenary there. The change in entry angle would be miniscule. It also would be a transient, one half cycle later the cable would tug in the opposite direction. It would be an oscillating, not linear motion. Our collective field experience is that the chairs swing more than the cable itself does, right? Something to start watching for on the longer stretches on a (cross)windy day - like the saggy part of the Glades triple just above GN.

It's not just the wind velocity, but more importantly the wind angle that effects lifts more than anything. You can have a chair that could run in say a 60mph headwind without a problem (short of having to practically pull some smaller folks off the chair at the top), but yet other times you can have that same chair shut down in say a 30mph wind if it's in more of a crossing direction. You get that gust acting on that glorified sail that a loaded chair is at the wrong angle and the lateral forces it can exert on the haul rope can be large. Just remember how the grip sways - parallel to the haul rope, so in head/tail winds you get little of any lateral forces trying to displace the haul rope from the sheaves. With the side/cross winds, the grip doesn't sway that way, and those forces get exerted on the haul rope in almost a twisting fashion, which can act to displace the haul rope from the sheaves (One of Mount Snow's lift guys was trying to explain all the nitty gritty details of wind angles and wind holds to me over a few beers a couple of years ago, and he went into WAY more detail than that).

As the saying goes, "it's all Physics "

[skidogg]

just a guess on my part,judged on 1 pic of a ski stuck in a chair, the chairs look to have been moving some on the ground

[DrJeff]

just a guess on my part,judged on 1 pic of a ski stuck in a chair, the chairs look to have been moving some on the ground

If they were moving forward because of the drive motor still running, I'm guessing it wasn't for too long as from the report it sounds like the mechanic up on the tower was in constant contact with the mechanic at the bottom of the lift. And I'd imagine he was yelling "stop" (or some other 4 letter word that might begin with the letter S ) as soon as the haul rope derailed

Some of that forward tilting of the chairs in the snow could have also been caused by the descent path they took. Since I'd imagine that it wasn't straight down, but more of a rocking/swaying motion, followed by some attempted "bounce" in the haul rope as the chairs got to the ground and the stretch in the haul rope evened itself out over the entire length of the haul rope

[rogman]

Any word on the extent of the injuries, or does Sugarloaf continue to hide behind HIPAA regs? They can't release individual information or names, but the extent of the injuries should be available. Just to be clear, this is what the HIPAA regs say:
"There are no restrictions on the use or disclosure of de-identified health information. De-identified health information neither identifies nor provides a reasonable basis to identify an individual."

[SkiDork]

I was thinking about what to do if this ever happened to me. I'm guessing I would want to stick my feet straight out in order to avoid having the lower legs mangled beneath the chair... Other thoughts?