Lisbons funicular suffers catastrophic runaway (03/09)

[bahnause]

Having re-read the report, I'm now more leaning towards the service brake being designed, at least originally, to be capable of stopping a detached tramcar but either a later modification or some other development reduced its effectiveness. The sanding equipment would certainly help with adhesion, though I don't see its mention in the report - perhaps it was not working for whatever reason?

Regarding the thread-braked wheels, I am unsure of their significance in the event of a broken cable. They certainly are in normal operation with balanced loads.

The rope's service life of 600 days, as stated in the preliminary report, is very short compared to other systems. This may suggest that there are problems with wear and tear, possibly at the connection between the rope and the 'trambolho'. Typically, these connections have a service life of 4–5 years, whereas the rope itself has no such limitation. However, I have not seen this type of connection before, so I am unsure of its design. The lift's special design and the long operating times probably also play a role.

 

[hexagon789]

Regarding the thread-braked wheels, I am unsure of their significance in the event of a broken cable. They certainly are in normal operation with balanced loads.

The rope's service life of 600 days, as stated in the preliminary report, is very short compared to other systems. This may suggest that there are problems with wear and tear, possibly at the connection between the rope and the 'trambolho'. Typically, these connections have a service life of 4–5 years, whereas the rope itself has no such limitation. However, I have not seen this type of connection before, so I am unsure of its design. The lift's special design and the long operating times probably also play a role.

I was thinking more of sand counteracting over-lubrication.

Some would end up in the cable slot, some would end up on the upper face onto which half of the blocks of the cable trough brakes bear upon.

The tread wheel brakes would likely be of little use other than as a parking brake in normal operation.

 

[Belperpete]

The cars have sanding equipment.

The cable slot brake has shoes which bear both down and up on the Z profile:

View attachment 188125

View attachment 188126
In the second photo, that pipe in the middle is a sanding pipe, there's one each end.

Looking at that diagram, there looks to be plenty of opportunity for getting lubricant on the bottom brake blocks if the cable in that cable slot is well lubricated. Agreed that the top brake blocks would still be effective, but with the bottom blocks ineffective you would have lost 50% of your braking force.

I am not sure how much of the sand sprayed down that slot would actually land on the braking surfaces of the brake blocks. But there is also the question of how often the sanding equipment is used, and how often it is tested? If it is not regularly used, then it needs to be regularly tested. Do we know how often it was tested?

 

[hexagon789]

Looking at that diagram, there looks to be plenty of opportunity for getting lubricant on the bottom brake blocks if the cable in that cable slot is well lubricated. Agreed that the top brake blocks would still be effective, but with the bottom blocks ineffective you would have lost 50% of your braking force.

I am not sure how much of the sand sprayed down that slot would actually land on the braking surfaces of the brake blocks. But there is also the question of how often the sanding equipment is used, and how often it is tested? If it is not regularly used, then it needs to be regularly tested. Do we know how often it was tested?

Indeed, it almost raises more questions than are answered really.

The final report will hopefully address all these.

 

[Belperpete]

The rope's service life of 600 days, as stated in the preliminary report, is very short compared to other systems. This may suggest that there are problems with wear and tear, possibly at the connection between the rope and the 'trambolho'. Typically, these connections have a service life of 4–5 years, whereas the rope itself has no such limitation. However, I have not seen this type of connection before, so I am unsure of its design. The lift's special design and the long operating times probably also play a role.

When you are comparing with other systems, what other systems are you comparing with?

With lifts, for example, the cables run vertically. With funiculars, the cables run semi horizontally, so have to be supported along their lengths. The cable moving across these supports adds extra wear that you don't get with lifts. Likewise the angle at which the cable meets the connection to the car will likely vary along the journey. Especially in this case, where the route turns a corner. This constant flexing of the cable at the point where it is fixed to the car would cause fatigue. Again, not something that would be experienced with a system like San Fransisco where the cars are attached and detached from the cable.

I am assuming that the cable doesn't just run along the bottom of the slot? There are rollers in the cable slot to support the moving cable? And likewise some kind of guide wheels to guide the cable where the route turns the corner? And all these are regularly greased?

 

[Ken X]

Suspension ropes are a consumable item item in such installations. The working environment should be a constant so the life is reasonably predictable given consistent rope quality.

I would expect the renewal period to have been determined over many years of measuring and inspection. Early failure indicates either a change in environment such as a seized pulley or mechanical damage to the rope or it's terminations. A change in rope manufacture or design may alter life expectancy but this could be managed by regular inspections knowing that a parameter has been changed.

My fastest wearing lift ropes were on a bank of four, two storey lifts which needed new ropes every eighteen months. We knew from the start they were going to be heavily used and so it transpired. The engineers monitored them closely and planned the regular renewals.

 

[Taunton]

Comparably to San Francisco, the Gloria has a succession of small metal inspection covers against the slot, each over a pulley wheel or other part of the mechanism allowing it to be serviced or replaced. Among other things, the San Francisco (and doubtless Lisbon) maintenance crews need to have acute hearing, they can occasionally be seen strung out along the middle of the street, listening intently for some tell-tale sound of how things are going under the slot. There also needs to be a means to drain rainwater from the slot, and periodically sluice it out from accumulated dirt and small debris. For the old London conduit tramway this was a considerable part of its maintenance.

 

[boiledbeans2]

When I visited Lisbon in 2022, Gloria was shut with the bogies exposed as mentioned in one of the posts above.

I spoke to the driver of the similar Lavra funicular. She mentioned that the down driver has full control. At the timetabled departure time, the up driver presses a bell to communicate to the down driver that the up tram is ready to depart.

Then the down driver drives both trams. The up driver retains an emergency button which stops both trams. This is what I recall of the conversation.

 

[Flange Squeal]

I am not sure if its been mentioned that one of the deaths was a UK man who was a transport enthusiasts.
I wouldn't be surprised if he was a member here. RIP.

Third British victim of Lisbon funicular crash was Anglesey man

Sixteen people died when the funicular crashed into a building in the Portuguese capital.

www.bbc.co.uk

The Talyllyn Railway posted the following on their Facebook page a day ago:

We are deeply saddened to hear about the passing of David Young who was aboard the Glória Funicular in Portugal during the accident that occurred last Wednesday.
David was a Talyllyn Railway volunteer of many years starting as a Tracksider parent, he later joined the Outdoor Gang on track maintenance parties and also enjoyed a quieter day as an attendant with The Narrow Gauge Railway Museum.
Our heart goes out to his family and friends, and of course to all of those who have also lost someone in this tragic accident.
Today our trains will be carrying black ribbons in his memory.

Source: https://www.facebook.com/story.php?story_fbid=1181769117313182&id=100064403152993

 

[bahnause]

When you are comparing with other systems, what other systems are you comparing with?

With lifts, for example, the cables run vertically. With funiculars, the cables run semi horizontally, so have to be supported along their lengths. The cable moving across these supports adds extra wear that you don't get with lifts. Likewise the angle at which the cable meets the connection to the car will likely vary along the journey. Especially in this case, where the route turns a corner. This constant flexing of the cable at the point where it is fixed to the car would cause fatigue. Again, not something that would be experienced with a system like San Fransisco where the cars are attached and detached from the cable.

The comparison refers to other funicular railways and the underlying regulations and recommendations. I don't have the relevant standards to hand, but Jakob Rope Systems has an excerpt from the EU standard EN 12927 from 2019.

 

[bahnause]

Over the past few weeks, I have been visiting numerous new cable car construction sites. In accordance with the latest standards, most of these cable cars no longer have safety brakes. A good example of this is the new Schilthorn cable car. Neither the first section between Stechelberg and Mürren nor the second and third section between Mürren, Birg and Schilthorn (which are not conventional cable cars but Funifors) have safety brakes.

In contrast, funicular railways still have safety brakes installed, as they do not usually have a continuous traction cable.

 

[35B]

Over the past few weeks, I have been visiting numerous new cable car construction sites. In accordance with the latest standards, most of these cable cars no longer have safety brakes. A good example of this is the new Schilthorn cable car. Neither the first section between Stechelberg and Mürren nor the second and third section between Mürren, Birg and Schilthorn (which are not conventional cable cars but Funifors) have safety brakes.

In contrast, funicular railways still have safety brakes installed, as they do not usually have a continuous traction cable.

So what are the emergency stopping provisions?

 

[bahnause]

So what are the emergency stopping provisions?

The primary and secondary braking systems in the drive. In the event of the break of the tracion cable, the ground or hitting the station. However, the ropes do not usually break.

 

[35B]

The primary and secondary braking systems in the drive. In the event of the break of the tracion cable, the ground or hitting the station. However, the ropes do not usually break.

So, in other words, the same primary dependency that appears to have failed in Lisbon?

 

[bahnause]

So, in other words, the same primary dependency that appears to have failed in Lisbon?

The images from Lisbon show quite clearly that it was not the cable that broke, but rather the metal socketing that failed. This is a notorious weak point, as it is almost impossible to inspect.

In order to largely eliminate the risk of the traction cable failing at the difficult-to-inspect metal socketing (casting cones) with which it is attached to the gondola, some cable cars have been using a continuous, endlessly spliced traction cable loop for several years.

With these detachable clamp connections, it is possible to secure the cabins in the stations and detach them from the haul rope, allowing the now empty haul rope loop to be inspected along its entire length without gaps and, for example, subjected to a magnetic induction test, which is only possible to a very limited extent with ropes divided at the sleeve connections.

In any case, most cable cars, chairlifts and ski lifts only have one cable. There is no backup option here either.

 

[Bletchleyite]

In any case, most cable cars, chairlifts and ski lifts only have one cable. There is no backup option here either.

Clearly in some cases a backup isn't possible. But where it is, why not have it? Yes, cost...but then when (and it's inevitably when) an accident does occur...

 

[bahnause]

Clearly in some cases a backup isn't possible. But where it is, why not have it? Yes, cost...but then when (and it's inevitably when) an accident does occur...

This is all part of a risk assessment. Even the unintentional use of the emergency brake poses a risk of injury to passengers. Evacuation due to a blocked brake is not necessarily a pleasant experience either.

 

[Bletchleyite]

This is all part of a risk assessment. Even the unintentional use of the emergency brake poses a risk of injury to passengers.

What sort of emergency brake are we thinking of here, are we thinking of one the passengers would operate? I was more thinking of something like lifts have, where if the cabin falls faster than it is designed to move downwards in normal operation pawls lock into a track and stop it.

Evacuation due to a blocked brake is not necessarily a pleasant experience either.

Better than being splatted on the floor.

 

[35B]

The images from Lisbon show quite clearly that it was not the cable that broke, but rather the metal socketing that failed. This is a notorious weak point, as it is almost impossible to inspect.

In order to largely eliminate the risk of the traction cable failing at the difficult-to-inspect metal socketing (casting cones) with which it is attached to the gondola, some cable cars have been using a continuous, endlessly spliced traction cable loop for several years. With these detachable clamp connections, it is possible to secure the cabins in the stations and detach them from the haul rope, allowing the now empty haul rope loop to be inspected along its entire length without gaps and, for example, subjected to a magnetic induction test, which is only possible to a very limited extent with ropes divided at the sleeve connections. In any case, most cable cars, chairlifts and ski lifts only have one cable. There is no backup option here either.

Thank you - that makes the mitigation involved much clearer.

 

[bahnause]

What sort of emergency brake are we thinking of here, are we thinking of one the passengers would operate? I was more thinking of something like lifts have, where if the cabin falls faster than it is designed to move downwards in normal operation pawls lock into a track and stop it.

It makes no difference whether it is activated manually or by a safety system.

Better than being splatted on the floor.

The number of times the safety brake is activated will significantly exceed the number of a broken cable. Such braking events are reportable incidents and, in the worst case, can lead to damage to the system (e.g. to the suspension cable).

 

[HighlandStorm]

So, in other words, the same primary dependency that appears to have failed in Lisbon?

No, because continuous circulating monocable haul ropes are vastly more robust than secondary traction cables on aerial trans, bi cable gondolas or funiculars.

 

[WessexEclectic]

Lisbon funicular crash initial report reveals litany of failings - BBC 20/10/25

A preliminary report into last month's funicular crash in Lisbon that killed 16 people including three British nationals has detailed a litany of failings.

Portugal's Air and Rail Accident Investigations Bureau said an underground cable - which acted as a counterweight between two carriages and broke, prompting the crash - was defective and had never been certified for passenger transportation.

 

[stuving]

There is now an English version of this interim (called preliminary) report on the GPIAAF website (until just now the link was mis-set to the Portuguese one).

 

[TheLastMinute]

Wow, that preliminary report from GRIAAF really is quite remarkable. The summary of relevant findings to date (reproduced below) comes to three A4 pages by itself. Given what they've found so far, it sadly feels like it was a case of when, rather than if, a major incident would happen.

Also, credit to GPIAAF for publishing a English translation of a fairly technical document for international consumption.

6. SUMMARY OF RELEVANT FINDINGS TO DATE

Regarding the haulage/equilibrium cable:

1. The cable between the cabins ruptured near the termination socket on cabin no. 1, inside the swivel, after 337 days of use. The exact mechanism of material failure and causal factors still need to be determined during the ongoing investigation, following analyses to be carried out.
2. The installed cable did not comply with CCFL’s specification for use in the Glória Funicular.
3. The installed cable was not certified for use in installations for the transport of people.
4. The installed cable was not suitable for installation with swivels at its ends, as is the system in the Glória (and Lavra) Funiculars.
5. The use of cables that were non-compliant with multiple specifications and usage restrictions was due to several accumulated failures in the acquisition, acceptance, and application process by CCFL, whose internal organisational control mechanisms were insufficient or inadequate.
6. Identical cables were in use for 601 days in the Glória Funicular (and 606 days in the Lavra Funicular) without incidents. For this reason, it is not currently possible to state whether the non-compliances in cable use are relevant to the accident or not.
7. The area where the cable broke was not accessible for visual inspection without dismantling the swivel.

Regarding the maintenance of the Funicular:

1. CCFL has subcontracted the maintenance of the funiculars to a service provider, with the current provider being responsible for maintenance since 2019.
2. The service contract establishes the obligation for the provider to deliver services with the diligence and quality required for the type of work involved, in accordance with the terms and conditions set out in the specifications and contract, respecting legal standards and industry best practices.
3. Nevertheless, the service provider’s workers essentially act as labour for CCFL, being trained on the job and performing interventions under the direct supervision of CCFL’ inspectors.
4. There is no guidance or supervision from the technical staff of the maintenance service provider regarding the specific manner in which the work should be carried out.
5. There is evidence that maintenance tasks recorded as having been performed did not always reflect the work that had actually been carried out, and that critical tasks were being executed in a non-standardised manner, with varying execution and validation criteria.
6. The maintenance plan for the Ascensor da Glória is noted has complied by the service provider and accepted by CCFL supervisors.
7. The inspections scheduled for the day of the accident and preceding days were recorded as completed and workers were present at the site on those days, however, there is evidence that they were not performed during the recorded timeframe.
8. On the day of the accident and before, the cable was not inspected in the pit, nor was this inspection foreseen in the plan. Cable lubrication, scheduled on a weekly basis, is recorded as having been performed on 28th of August. The monthly cable inspection is recorded as having been performed on the 1st of September.
9. The location where the cable ruptured is not accessible for inspection during the maintenance procedures foreseen in CCFL’ maintenance programme; inspection there is only possible by stopping the cabins and dismantling the swivels, a procedure that requires a downtime of at least two days.

Regarding the cable socket termination:

1. The analysis carried out so far on the cable socket termination to cabin no. 1 shows the existence of areas considerably less dense or even voids within the casting.
2. The maintenance service contract explicitly assigns responsibility for the cable assembly work, including the execution of the socket, to the service provider, with CCFL limited to supplying the cable.
3. The production of the sockets follows a historical empirical process within the company, passed down through generations, with no written procedure in CCFL’ documentation system defining the treatment for preparing the cable strands, the composition and preparation of the casting alloy, or the execution and quality control of the socket.
4. The maintenance provider has no information on how to make the sockets.
5. At the time of manufacturing the sockets, no tests were conducted to verify the quality of the casting.
6. The composition, execution, and control of the casting of the sockets does not comply with the applicable European standards.
7. The critical area of the cable-to-socket connection, where the cable ruptured, was not accessible for visual inspection without disassembling the swivel.
8. Considering the history of cable use in the Funicular, the risk arising from the degradation of the cable condition, including that area, was indirectly controlled by limiting the cable’s usage to 600 days.

Regarding the braking system of the cabins:

1. The cable failure detection system incorporated in the Glória Funicular operated properly, cutting the electrical power to the cabins in order to trigger the emergency brake system, to safely stop the cabins.
2. The cabin braking system was not effective in stopping the cabins, despite all the existing brakes, both automatic and manual, being applied in cabin no. 1.
3. No calculations are known for the emergency brake of the cabins.
4. The historical information available suggests that the brake system was modified a few years after the electrification of the Funicular, with some components having been removed. There are also indications that the weight of the cabins has increased significantly since electrification, with differing reports regarding the current weight.
5. The cabin brake system was frequently adjusted by the maintenance service provider, following reports from the brakemen.
6. The anomalies that motivated these adjustments were rarely recorded in the defect logbook maintained by the brakemen, just as the maintenance service provider seldom documented the adjustments performed in the intervention sheets.
7. CCFL has not defined, in the Funicular maintenance procedures, the adjustment values for the various mechanical components of the braking system; only the wear limit value for the brake pads on the Z-rail is specified.
8. The maintenance service provider did not establish any quality control system for the work performed on the braking system.
9. There was prompt response from the maintenance company to any intervention requests made by the brakemen, and any anomaly considered to compromise safety led to the immediate stoppage of the Funicular until resolved.
10. CCFL has no record of ever having tested the emergency brake in a cable failure situation.
11. Among various CCFL technicians and workers connected to the Funiculars, there was the perception that the system’s safety depended entirely on the cable, and that the braking system was not effective in stopping the cabins without the cable. For this reason, great care was taken in controlling the cable, notably limiting its use to 600 days, well below the expected lifespan. However, this perception was never organisationally translated into a reassessment of the system’s safety conditions.

Regarding the legal and supervisory framework of the Funicular:

1. The Glória Funicular (and the Lavra Funicular, with identical technology) was excluded from the scope of Decree-Law No. 313/2002, which transposed Directive 2000/9/EC into national legislation, applicable to cable installations for passenger transport. Although that national legislation provided a specific regime for installations already in existence at the time of its entry into force, it was considered excluded under one of its exemptions, corresponding to “traditional cable-driven electric cars.”
2. With the entry into force of Regulation (EU) 2016/424 and Decree-Law No. 34/2020, the exclusions were altered; however, the Glória and Lavra Funicular, being classified as national monuments, remained excluded because they were considered cable installations classified as installations of historical, cultural, or heritage interest, having entered service before 1st of January 1986, still in operation, and allegedly having undergone no significant design or construction alterations.
3. Thus, as far as could be determined so far by the investigation, all safety aspects concerning the operation of both funiculars were the exclusive responsibility of CCFL as the operating entity, without supervision by any independent public or private entity, and without an effective legal framework for their operation unless significant changes were made to their infrastructure or subsystems.
4. The fact that the funiculars were considered excluded from the legislation’s scope in no way prevented the application of the same rules as those for other installations, with the necessary adaptations to their specificities.
5. GPIAAF found that the electric trams of CCFL are in an identical situation due to the lack of a legal framework for the technical regulation and safety of electric systems operating on non-reserved tracks. Consequently, the maintenance and safety conditions of electric trams, historic, modernised, or modern, running on public streets alongside road vehicles, both at their commissioning and during their operational life, are not subject in Portugal to compliance with any rules other than those defined by the company itself, nor, crucially, to any form of independent supervision.

 

[endecotp]

Well worth reading all of it.

 

[bahnause]

Well worth reading all of it.

Torsional forces contributed to the wear and tear that caused the accident on Mottarone. Ultimately, a fracture occurred near the socket. These accidents are becoming increasingly similar.

 

[Ken X]

As a retired Lift and Crane examiner I found the report a very interesting read.

I have my opinions re the causes and have discussed the incident with colleagues in the industry. We await the publication of the full report with interest.

As with the majority of incidents there are several threads to the investigation. Its a complex web of factors which resulted in the ultimate failure and the sad loss of several lives.

 

[AndrewE]

I think section 5.2.2 is most informative. It is clear that it is known within the industry that ropes with single-lay strand direction shouldn't be installed in any way that they can unwind, and that if they do they lose a large proportion of their strength. (Hence the manufacturers prohibition on using them with swivels.)
It will be interesting to see what the metallurgical work on the broken cable ends reveals..