There's nothing there to stop it, other than the track and I suppose more significantly the trench ending, in the pavement. I think it's significant and concerning that the investigators haven't found out who's responsible for safety, which doesn't mean that nobody cared, quite the opposite, the thing had a lot of attention, just of the wrong things - easy to say - perhaps I should instead say they tested the things that were testable and in the absence of a proper legal structure around it that might have required extra equipment they did what they thought was right. The parallel judicial investigations won't be too happy about that, I don't suppose. But at some point it's unforgivable. We've had over 100 years to make conventional lifts work and they're safer than stairs for a reason. Public transport isn't supposed to do this.
During the investigation into the accident in 1932, it was discovered that the emergency brake had been disconnected in 1906 because it often activated accidentally. An alternative had not been found and the cars had remained without an automatic brake or indeed any effective brake on a 25% gradient from then onwards. A new system was only installed in 1934.
What did the rack do?
If the lower car had been further uphill when the cable snapped, the it would have run down with more force. If this had been sufficient to break the cable grippers in the trench, the lower car would likely have launched itself across the road and square below. Likewise if the upper car had not derailed on the bend, and had made it down to the bottom, there would have been precious little to stop it doing similar.
I rode on the funicular in Stuttgart last year. The information leaflet mentioned that a number of years ago it had been withdrawn from service, and its future had been in doubt, as extensive and expensive rebuilding was needed to meet EU safety standards. Without a safety regulator monitoring the Lisbon funiculars, who would enforce similar actions on them?
- there are other solutions of course such as wedge something into the cavity where the rope sits. I'm not advocating any particular solution other than saying plenty exist.My two questions (which were combined into the same post by the double post prevention system) were in response to different posters and related to different tramways - the first to the Lisbon funicular, the second to the Great Orme Tramway. I'm not aware that the Great Orme Tramway uses a rack.
It would help if posters such as yourself actually mentioned which tramway they are talking about! Or at least not cut the text that you are responding to, such that the context is totally lost.
I assume it provided the braking.
My wife and daughter were on the funicular three weeks ago. They took lots of photos on board. Presumably, the unit is now a wreck. They were staying in a hotel next to the track. It's the semi- circular building on the right of your photo - a former theatre.
Magnetic brakes on trams achieve deceleration of about 25% of gravity. The average gradient of the funicular is quoted as 18%. So with no cable and no other brakes effective, the magnetic brake would probably stop a runaway eventually, but unlikely to be quickly enough. It would also need batteries and other equipment on board the car, so it could still operate if traction power was lost.
Magnetic track brakes do not get a mention in the preliminary report (English language version here https://www.gpiaaf.gov.pt/upload/processos/d054239.pdf ) so it can be assumed that this system was not fitted with them.
I'm sure they will be testing the brake on the surviving car. This also dropped back when the cable became detached, which probably means its own brake wasn't adequate either and therefore it is most likely a systematic problem not a one-off defect in the brakes of the other car. The alternative explanation is that the other car might have come to a halt after a short time (pneumatics isn't instantaneous) if it hadn't hit the end of the track first.
www.cablecarmuseum.org
Whatever braking is provided should surely be able to pull it up within the limits of the trackwork, especially as it had apparently just set off in the opposite direction when the fault developed, and thus passed through stationary to roll back in reverse.
That is quite an important difference. The cable groove will presumably have been kept well greased to reduce wear on the cable, whereas rails are generally not.
I did not want to comment on the issue of 'lubrication' because, from the pictures, it is unclear to me how generously and in which places grease is to be found.
Of course, if it is measured at a place where the slot is not well lubricated, it will not give a good indication of how well the brake would perform somewhere where there is excessive lubrication. I can imagine a scenario where they might measure the brake performance at the terminal stations where the cars stop overnight, which might be difficult to access for lubricating because the cars are in the way.
I'm not keen on the thought that one driver can power all the motors without the other driver's co-operation. Putting the whole lot in series with both drivers having to close their controllers to make the circuit would mean both having to act before anything could move, but it would also mean no power for auxiliaries unless motoring (unless there is maybe a separate circuit returning via the rails?).
The other driver will have to co-operate, in that I've assumed (but didn't mention specifically) the usual sort of three-position direction switch - forward/neutral/reverse. You'd have both in neutral when stationary at the terminals - and in this state you could get half volts for the auxiliaries. To start a movement one driver will select forward, one reverse according to direction of travel; then both would need to select 'first notch' to start the traction motor current flow. You'd want a standard way of notching up; one first then the other? I wonder if there's an ammeter somewhere in each cab?
If both selected neutral and the auxiliaries were across the supply to each tram then it would end up with both in series on half voltage. Assuming no clever electronics, that would do something pretty odd to the lighting when the compressor started up!
www.bbc.co.uk
The cars have sanding equipment.
