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Italian tramway incident, 14 dead, 5/23/2021

Tramway accident Funivie Italy broken rope broken cable Stresa Mottarone

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#1 Kelly

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Posted 06 June 2021 - 02:04 PM

Stresa Mottarone Italy, town tramway has departed from the support rope 14 dead.

Not normally a topic for this forum, but due to the commonalities with skilifts, the horrific nature of the incident and the spotty reporting, this topic will give an overview of this incident for the forum readers. This will be a multipart post.

Part 1
Tramway Basics
In North America this ride type (ropeway) is referred to as a tramway (shortened from the term “aerial ropeway tramway” and often referred as the singular “tram”).
Typical tramways have two cabins, one per-side, that go back-in-forth (jig) between terminals, it is also referred as a jig-back tramway or reversable tramway.
There are 3 common types of classifications for aerial ropeways: mono, bi, and tri are terms used for rope support and hauling means.
Mono cable is commonly found with chairlifts.
Bi cable has a single support or track rope and a haulrope. Bi cables are associated with lower loads, they are not as common in North America but are still being manufactured worldwide.
Tri cable has 2 support ropes and a haulrope.
Typical tram car key elements:
Carriage connects to the haulrope by a socket joint or mechanical clamps and rides on trackrope(s).
Socket joints can be poured metallic alloys or of resin, or of a mechanical clamp – all resemble a pyramid shape and due to that shape tighten with tension.
Hanger Arm connects the carriage to the cabin.
Cabin holds the people along with operating controls, phone systems and in North America an operator.
Tram control systems consist of: speed, measuring/tracking and braking control.
In nearly equal loaded cabins; speed is mainly controlled electrically with the brake primarily applying holding force just as the cabin stops – this can be equated much like driving an auto up a steep road then slowing and stopping.
Tram distance/tracking measuring devices tell the speed control what to do at key points of the trams travel. These tracking devices can be either manual but now mostly electronic. Very early tram speeds were manually controlled, now are all electronic with manual override capability.
Tram stopping systems:
Trams are unique in that they have two separate braking systems.
Haulrope brakes: Brakes can be positioned much like chairlifts such as: disk or drum before the gearbox and disk style at the bullwheel flange(s). As with chairlifts, brakes are failsafe.
Trackrope brakes: In the advent that the haulrope brake(s) does not work the carriage can be stopped with a brake that clamps on the trackrope. If the haulrope fails the trackrope brake is applied. If a socket or socket connection fail the trackrope brake is applied. Due to the low friction of tramways, cabin/hanger weight, haulrope weight - trackrope brakes must be almost applied instantaneously as the cabin potential for unstoppable acceleration is likely.
Like the haulrope brake they are failsafe in the sense that they are spring applied and this spring is held in the "unclamped" position by hydraulic means.
Early tramways had manually setting trackrope brakes, now they are all automatically set (tripping the hydraulic system) with manual override capability.
Brake testing is performed on a routine basis; during testing to ascertain single brake deceleration and holding capability it is common to deactivate or block-out non-tested brakes by either electric or manual means. Brake testing follows manufacturer test points and take considerable time and a number of technicians to monitor the test sequence consequently these are performed during nonoperational hours or in the “off-season”. Manual brake “block-outs” are easily identifiable and must be stored in a secured place to prevent inadvertent use.
Daily Preoperational Maintenance Checks
Before loading to the public, daily operations and inspections must be performed on the all of the components listed above. This also includes socket integrity.
Cabin Operators
There are no cabin operators in this section of tramway. The operator controls are covered over. Phone and emergency instructions are provided.

Part 2 below
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#2 Kelly

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Posted 06 June 2021 - 02:05 PM

Part 2
Existence of Italian Tramway Expertise:
Italy, due to the nature of topography has a wide and long track record with tramway design and manufacturing. One of the bigger ropeway manufacturers is the large industrial conglomerate Leitner.
Italy also has a long track record with design and manufacture of wirerope. One of the larger wirerope manufacturers is Redaelli.
Tramway Location:
Stresa Italy – bottom terminal is near Lake Maggiore’s shoreline.
Tramway ownership:
This tram is not in the normal terms associated with a ski resort but rather is owned by the city/region of Stresa. To keep things simple I will refer to the ownership as – Stresa.
Tramway Operatorship:
Stresa leases the operation to an outside Contractor, at this point I am unsure if Stresa or the Contractor provides the employees or just manages the money. It is unclear at this point if the Contractor has any personal maintenance experience.
Tramway Maintenance:
There are two pathways for maintenance on this tramway.
Day to day maintenance seems to be done by a very experienced technician under the employee of the Contractor. That technician is assisted by apprentice mechanics when needed.
Deeper maintenance expertise is a fixed cost contract provided by Leitner by phone or a Leitner Service Representative.
The tramway maintenance skill pyramid might resemble this…
Apprentice Mechanics
Technician – on site
Factory Technician – off site
Factory Engineering and deeper knowledge base
Rope Inspections
Leitner performed magnetic inspections in November, it is unclear which ropes were inspected but it would seem in their answers to media inquiries that this was directed at haulrope inspections. No x-ray socket inspections were mentioned.
Tramway Financial History:
Past news articles indicate the inability of this ride to generate profits or for Stresa to find any profits that may have been generated. This tramway underwent recent modifications and updating by Leitner. It is unclear if Leitner did any carriage brake updates or maintenance (see carriage change below).
News articles indicate that Stresa owes Leitner really more than the tram could ever pay back within a reasonable time frame. My assumption is that Stresa will pass another tax levy to pay for those modifications and Leitner would not ask for ownership in lieu of payment.
Italian Ropeway Oversight:
Italy does have ropeway inspectors, at this point it is unclear if they inspect this ropeway more than once a year. Unlike some United States inspection agencies who seem to exist to fill a slot in an organization chart the Italy agency and this inspector are widely respected. During media interviews the inspector frankly said if the brake “fork” was installed this was the cause of the runaway cabin.
Tramway Type:
Two stage: Actually, this is two different tramways – lower and upper.
Bicable = one support rope (track) and one haulrope.
Carriage brake is spring closed and normally held open by a hydraulic system.
Cabin capacity: 40
Cabin load at the time of the incident:15
Total Fatalities: 14
Original Installation: 1970
Carriage and hanger replaced around 2002
Haulrope resocket time period: 5 years
Next resocket: November 2021

see Part 3 below
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#3 Kelly

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Posted 06 June 2021 - 02:08 PM

Part 3
Incident Particulars
Initial reports indicated a tram car had fallen from its support rope in the upper stage. Single support ropes are inherently less stable and weather or tower interaction may have been involved with the detachment as the cabin final resting was just downhill …
Based on the next round of media reporting showing the haulrope was on the ground it was obvious the haulrope had failed.
The failure seems to be at or near the socket assembly, however the socket is buried in a tree.
Carriage brakes have also been known to “mis-pinch” and slip to the top of the rope making them ineffective – this was also thought as the cause.
Brake Blocks Engaged During Operation
In the next set of pictures gathered by the media; show a carriage brake block – by their shape their referenced as “pitch forks” or “forks”.
It became known that the haulrope failure happened just as the car was docking in the upper terminal – the distance to the tower is +1,000 horizontal feet.
Haulrope/Socket Failure Cause
Pictures clearly show there is very little if any actual haulrope failure.
The individual wire “broom” has pulled out of the socket.
Additional visual inspections will show:
- If the socket was poured correctly
- If the wires were correctly prepared
- If the correct socket filler was used
Technician and Management Statements
Interviews with the employees indicated that brake blocks were used in the past.
Interviews with employees indicated there was no preoperational checks as paying passengers rode on the first car up.
Pictures and videos show Covid load spacing being violated.
The on-site technician indicated there were issues with this car’s brake and he discussed the use of the blocks with the Factory Service Representative the day of the incident. He also indicated this was a recent practice to install the blocks while open to the public. He also indicated past discussions with this practice with the tram Contractor, citing they needed to operate to make money. See covid loads above.
The Service Representative indicated he wasn’t aware of the daily practice.
The Contractor indicated he wasn’t aware of the daily practice.
Past Evidence of Brake Disengagement During Operation
At the insistence by all parties that brake disengagement by blocks was just a recent practice, yearly video and pictures show the brake blocks in place since 2014.
An outside expert has been retained to examine the incident and make a determination of the cause of the incident.
Excessive Haulrope Vibration
In viewing the many videos taken over time, they show harmonic vibration of the haulrope near the carriage as the cabin approached towers and terminals.
Harmonic vibration will amplify rope fatigue life.
Based on dates of videos - this vibration has existed for a very long time and did not just occur within the recent history of this tramway.
Past Similar Failures
Tiflis Georgia had a haulrope failure with brake failure 6/1/1990 20 fatalities and 15 injuries.
Brakes on both carriages were commonly blocked rather than redesigned or repaired.

Posts above will be edited when more information is gathered.
Part 4 with more info is next
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#4 liftinspect

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Posted 07 June 2021 - 07:38 PM

I am certainly not an expert on Trams. But 2+2 is equaling 3 for me at this point. It is hard for me to believe that the haulrope socket was in operation for 4.5 years and suddenly the haulrope pulled through the socket. I would think there would be visible external broken wires at the outer end of the socket. Seems like if the socket held through all the abuse, inadvertent track rope brake setting and vibration. I would think the failure would occur at or near the outer end of the socket??
Unless there was some kind of problem with a resin poured socket. My question still is what kind of socket was it?? Poured resin, hot poured or mechanical??

#5 Kelly

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Posted 09 June 2021 - 11:14 AM

Part 4
Technical information for our readers…
Rope sockets (end connections) are quite common and not unique to the ropeway industry. Some can be quite small and be found in residential deck railings.
Attached File  Socket-small.jpg (100.18K)
Number of downloads: 48Attached File  Socket-small.jpg (100.18K)
Number of downloads: 48
And some quite large.
Attached File  Socket-Large.jpg (99.52K)
Number of downloads: 56
Depending on the connection detail they can have a open or closed “end” loop.
Attached File  Socket-Open-Closed.jpg (90.33K)
Number of downloads: 78
Showing a socket broom in the socket.
Attached File  Socket-Dirty.jpg (127.02K)
Number of downloads: 97
There are a number of items worth mentioning in this image.The wires should be a little cleaner, the rust from the socket should be removed, wire turns should not be on top of each other and the broom more evenly spaced. This is a how-to-don’t picture, ironically from an Italian company.
Poidonia – Mooring and Towing – Novi Ligure, Italy https://www.posidoni...mpany/posidonia
Poidonia's socket is used as an example only - it is not associated with this ropeway.
Clean socket Attached File  Socket-Good.jpg (98.19K)
Number of downloads: 103
Socket strength is designed to be the same as the rope or a little better. This link shows a pull test with sockets: https://www.youtube....h?v=Jj_K6bGQIfM
Notice the rope failed just outside of the socket.
Track Rope Brakes
German news agency did a very nice explanation of a trackrope brakes and blocking device along with an animation.
This is a screen capture courtesy of ZDF with added component labels.
Attached File  ZDF-brake-for-web.jpg (100.52K)
Number of downloads: 75

ZDF Brake Link: https://www.youtube....h?v=NOz3KQYuiQY
The brake shoes look quite small but all have been tested to be quite effective.

Graphic via repubblica which is also quite good: https://torino.repub...ente-302857835/
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#6 Kelly

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Posted 17 June 2021 - 05:52 AM

In respect to the families involved with the incident and the absence of any technical details the video showing the failed haulrope will not be posted ~ Forum Admin
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#7 liftinspect

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Posted 17 June 2021 - 06:05 AM

Picture of sockets

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