Anyone know what's happening at Bolton on the Timberline chair?

edited November 29 in NELSAP Forum

Some are saying that it's just a bullwheel replacement, but i didn't think the haul rope came off of the sheave train during that kind of maintenance.


Comments

  • That does not look intentional...
  • Bullwheel repair. As seen on their FB page a minute ago.
  • Scary intentional?
  • Yeah, definitely Bullwheel repair (as djspookman and their FB post showed). I was involved in a bullwheel bearing replacement at Sunapee in the summer back when I worked there. In our instance we removed the chairs from the section of haulrope that was taken off the towers, but in all reality (like the photos above) you really don't need to. As long as when the haulrope is lowered you have people on the ground available to lay the chairs down nicely so that they don't end up standing and holding the haulrope it's A-OK to do this.

    In the first photo you can see what looks like a pole leaning up against the haulrope on the right hand side. This pole is set through loop on a big plate clamp that clasps the haulrope and allows a block and tackle to be connected to it. A similar plate clamp/pole/block and tackle setup is used on the other side of the section of haulrope you're trying to de-rope or de-tension from the lift. Once these pieces are in place, the block & tackles are tensioned and the section of haulrope becomes detensioned such that it can now be de-roped from a tower or bullwheel - in this case, the return bullwheel. This whole setup is put into place in order to allow the lift to remain at regular or mostly regular tension while it is being worked on. The poles I mentioned earlier are used to prevent unnatural twisting of the plate clamp and haulrope. This setup is also used when a lift haulrope is being shortened due to stretching over time.

    I'll see if I can dig up some pictures for a better idea of what's going on.
  • Here we go...Sorry these pictures are so small, they're from 10 years ago.

    First image below shows the block & tackle/two poles we used when we took 25' of haulrope out of the summit lift. Nearly full tension is on the lift at the time, with that tension go through the block & tackle as well as the large slings. The poles make sure it doesn't twist. Note the actual haulrope for the lift laying on the ground to the right of it.


    Second image: This shows the plate clamps that are used. 18 bolts a piece and all 18 must both be new and then thrown away after use. In this instance we only used one block & tackle for the other plate clamp down the hill anchored to a tower base. No pole here as there wasn't much twisting and it's really only meant for instances where there's a block & tackle. The slings going from the clamp to the lift terminal are intentionally twisted to prevent fraying, to make the whole bundle of slings tighter, and to prevent the possibility of getting damaged in the event something sharp gets dropped on them. Again note the fully tensioned haulrope on the right side of the clamp and the slack (same) haulrope on the left of the clamp.


    Third bonus image showing a day later with the bullwheel on the ground in preparation for a new liner around the outside of it and new bushing for the center. During this we also shortened the haulrope 20' and smoothed out one of the two splices for a more comfortable ride.

  • edited November 30
    hey thanks for the insights! Any idea what material is used for the lining? (liner?)

  • I don't know for sure, but I believe it's a composite of rubber and a few other "ingredients." I know when handling the bullwheel liner it was definitely rubbery to the touch, but a lot harder than your normal rubber tire. There are also short (I think) brass rods spaced every so often over the circumference of the liner to allow electrical conductivity from the haulrope to the bullwheel itself. This is to account for lightning strikes to the haulrope.
  • that's fascinating, and makes me say "of course", but never gave it any thought before. Thanks for all of this, furthers my appreciation for mountain ops

  • edited November 30
    Its definitely a rubber mix. I've been involved in removing (and replacing) a liner before without even removing the haul rope. The old one had to be chipped out piece by piece while the new one is laid in its place and the wheel moved little by little. It's a whole day or more affair!
  • newpylong said:

    Its definitely a rubber mix. I've been involved in removing (and replacing) a liner before without even removing the haul rope. The old one had to be chipped out piece by piece while the new one is laid in its place and the wheel moved little by little. It's a whole day or more affair!

    I know that we did this before for the return bullwheel on the second lift pictured (SunBowl), though fortunately our crew didn't need to chip it out. It ended up pulling out without too much trouble. In the photos above, it was just easier to do it all at once.
  • Wow that was a good thread to read I had no idea thanks jonni very interesting
  • So, Jonni-- if I am extrapolating here--- in order to take tension off of the haul rope, you install a plate around the cable at two different locations attached to independent anchors-- one on the upline and one on the downline. Then, tension is taken on both of those to create a slack section that can come off the bullwheel and work can be done on it. Does that sound right?
    "Making ski films is being irresponsible with other people's money, in a responsible sort of way..." 
    Greg Stump
  • bmwskier said:

    So, Jonni-- if I am extrapolating here--- in order to take tension off of the haul rope, you install a plate around the cable at two different locations attached to independent anchors-- one on the upline and one on the downline. Then, tension is taken on both of those to create a slack section that can come off the bullwheel and work can be done on it. Does that sound right?

    Yes, that is 100% correct. There most likely other ways that it can be done, but those are the ways it was done in the two instances I was involved with.
  • Couple questions:
    Why would a bullwheel need to be replaced (as opposed to replacing the liner and bearings)?
    Last season I noticed a section of the haul rope had become lumpy on Timberline. It made me a little uneasy. Is that a safety concern?
    Bolton has been open the last two Saturdays. Snowflake failed the first Saturday and Vista the second, requiring the backup engines to get people off. Hopefully all the lift bugs have been worked out, because I have yet to make it to the top. ;)
  • I don't believe there was a complete bullwheel replacement, just replacement of bearings and the liner (and perhaps the bushings while they were at it). Looking at the photo that Bolton posted to their FB page, I'm guessing it was more economical to remove the bullwheel completely and truck it down to their shop to work on it. In the pictures I posted from Sunapee, the location of the bullwheel made it more economical to do the work in place.
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