16 replies to this topic

[Peter]

Investigation completed on Steamboat lift incident
Story by Matt Stensland
Steamboat Pilot
Thursday, January 3, 2013
Steamboat Springs — An investigation has been completed into why a Priest Creek lift chair with two people on it lost its grip on the cable and slid backward Monday at Steamboat Ski Area.

Colorado Passenger Tramway Safety Board spokeswoman Cory Everett-Lozano said an inspector determined the chair slid because of a worn-out grip on the 40-year-old lift. The grip might have been jostled as it went through the lower terminal, she said.

Everett-Lozano said the ski area will inspect all the grips before operating the lift again. She said that should be done before spring break.

The incident happened near the lower terminal when a chair with two people on it slid a short distance on the steel cable but did not strike the chair behind it. The lift was stopped immediately and unloaded, and no one was injured.

In recent years, the lift has been used only during busing periods and as a backup.



Priest Creek is a 1972 Heron-Poma double.

[boardski]

That is a long time to inspect all the grips, are they planning on replacing all of the grips? Maybe parts are still available from old Christie II. I have always thought they should start using that lift again on weekends and holidays but that is definately not good. I would presume parts are difficult to find for Heron-Poma lifts. I have not ridden that chair since Sundown was a triple (pre-1992).

This post has been edited by boardski: 05 January 2013 - 10:25 AM

[boardski]

boardski, on 05 January 2013 - 10:20 AM, said:

That is a long time to inspect all the grips, are they planning on replacing all of the grips? Maybe parts are still available from old Christie II. I have always thought they should start using that lift again on weekends and holidays but that is definately not good. I would presume parts are difficult to find for Heron-Poma lifts. I have not ridden that chair since Sundown was a triple (pre-1992).

After posting something about Snowbird, I was remembering a similar incident a few years ago on Wilberie lift where they found out the haul rope was too stretched (diameter not thick enough). I wonder if this happend to PC? They ended up replacing all the chairs and rope (old chairs from Gad 1 were used) and replaced the rope on Gad 2. No injuries occurred during this incident either, just a surprised ski patroller when he or she unloaded the lift and the chair came off with him.

[vons]

Superior Tramway carries/produces an amount of Huron-poma parts, plus there are parts from three lightly used Huron-poma lifts in the area

[egieszl]

boardski, on 05 January 2013 - 10:20 AM, said:

That is a long time to inspect all the grips, are they planning on replacing all of the grips?

The article is misleading since it confuses the grip inspection sentence with the date the lift is expected to operate again.

Priest Creek is a secondary lift and according to another article Steamboat was not planning to operate it again until March.

[skierdude9450]

vons, on 06 January 2013 - 10:11 AM, said:

Superior Tramway carries/produces an amount of Huron-poma parts, plus there are parts from three lightly used Huron-poma lifts in the area

I assume you're referring to Stagecoach ski area? Are those lifts still standing?

[boardski]

Correct me if I am mistaken but the Yellow Jacket and Little Hitch chairs (the lifts at Stagecoach) are still standing without chairs on the haul ropes. I don't know if they have been storing those chairs somewhere all these years or if they have already been sold to other ski areas. The Big Hitch chair was the former Timberline lift at Mary Jane until Panoramic Express was installed in 2007. The lower terminal of Timberline is still standing in its former spot. I presume the rest of the lift is being stored somewhere for future expansions (such as Vasquez Cirque??). I remember it took 2 weeks for Snowbird to get the Wilberie/ Gad 2 issue ironed-out, that's why I was surprised.

This post has been edited by boardski: 06 January 2013 - 05:04 PM

[vons]

There are parts at Stagecoach the chairs and grips from Yellow Jacket and Big Hitch where stored in the unfinished base lodge at least I remember seeing some photos of them being stored there.

[SkiBachelor]

In regards to Stagecoach, the carriers for both the Yellow Jacket and Little Hitch lifts are still on site. They currently reside under the framework of the new lodge that was once being built.

[shoemanII]

shouldn't have happened, of course. is the rope undersized? were the grips slip-tested monthly? were the grips match-marked after relocation, and migration checked frequently during the op season? this is not rocket science, but may be a reflection of ........................... sorry, about to rant. back on topic:

part of your annual NDT inspection should include a physical check of the grip. does the spring stack free length meet the minimum? install the grip on a mandrel sized at 94% of your rope nominal and check to see if the grip is bottomed out. you should know how to perform this check on all your grips, regardless of manufacture. how to perform this check on Heron grips is shown on the H-P grip drawing.

[Lift Dinosaur]

It;'s been awhile since I did annual maintenance on a Heron grip, but I do not remember any specification for the "mandrel sized at 94% of the rope diameter" .....
"you should know how to perform this check on all of your grips, regardless of manufacture"- can you elaborate on where this requirement comes from?
Thanks-
Dino

[Don Coyote®]

Lift Dinosaur, on 07 January 2013 - 09:19 AM, said:

....."you should know how to perform this check on all of your grips, regardless of manufacture"- can you elaborate on where this requirement comes from?
Thanks-
Dino

Perhaps this quote sounds a bit arrogant, but I agree with the basic principle.

If you don't understand the basic workings of the mechanism you are maintaining, then you should relinguish your responsibility a more qualified mechanic. (Or ask for assistance).

Ignorance is replaced with experience... we all have to start somewhere. (But someone appears to have dropped the ball on this particular lift).

[shoemanII]

hello mr dino!

i have a partial print showing a cross-sectional view of a 1972 heron triple grip. that view shows that a gap between the insert and grip body must be maintained when the grip is properly tensioned on the rope. this ensures that the grip is not "bottomed out" when installed. b77 stiplulates a minimum diameter of 94% from nominal. a nice check before installation on the rope would be placing each of your NDT sample group on a correctly sized mandrel.

the print also shows the minimum free length of the spring stack to be 3.94 inches (triple grip). broken washers are not allowed. also shown on the print are hints about proper fit-up of insert to the body, proper lubrication, etc.

if using his equipment, am sure mr ellis of superior tram will provide you with any technical help you need.

i'll refrain from further, unrelated comments.

[chuckm]

two items- shoeman's information is quite good and i am sure that in following it one would not have many problems with the grips- they would be identified on the ground. doing an inspection on 100% of the grips every year while relocating them takes only a little more time and is well worth it. Quite a few years ago i was helping out on an incident where the loaded chair had slid down the line dumping the passengers, and pinning the passengers in the chair downhill- it turned out that the mechanics were merely torque testing the spring pack in place- many of the spring packs had rusted so bad that they were not providing any grip but were testing well above the required torque- how scary is that! there was also some very uneven grip migration going on that could have been a clue to a problem.
secondly- grip pull testing- this is a very good test if done properly. be careful if a hydraulic or pneumatic tester is being used and be sure it is acting on the grip properly-not at an angle. sometimes the simple hoist and dynomometer may be better. just my .02 PS those Heron-Pomas were well built machines.

[boat mech]

Just a little clarrification

• Grips NDT'd at 20% per year
  
• Rope size is above minimum allowable
  
• Spring pack measured at 3.94"
  
• Plunger not bottomed out
  
• Grips are relocated and painted every year as well as slip tested
  
• Chair ran three days with a full load before incident
  
• No migration was detected before incident, fourth day of operation for the season.

Pictures and info will be posted in the SORT forum once investigation is complete.

[Peter Pitcher]

Well I would like to know what happened. I know that Steamboat has one of the best lift maintenance programs around so all the talk about mandrels and rope diameter are distractions. I wonder what was meant by a "forty year old grip was worn out". HP grips like all modern grips are a spring loaded clamps, they work with the rope expanding and contracting to maintain gripping force. What caused the grip to not contract after going around the bullwheel.

[Lift Dinosaur]

shoemanII-
Thanks for your response. My drawing shows checking for the gap on a nominal sized mandrel before installing on the rope. I did not correlate that to the 94% reduction from nominal since B77 also requires the design to incorporate provisions to accommodate a 10% reduction in haul rope diameter. I re-read where you said "should" - I thought I was missing a 'requirement'.
Dino