Paul of Covington Just curious: How do the brakes on San Francisco cable cars work? Do they grip a stationary cable or rail? I can't imagine conventional brake shoes on the wheels being effective on those steep hills.
Just curious: How do the brakes on San Francisco cable cars work? Do they grip a stationary cable or rail? I can't imagine conventional brake shoes on the wheels being effective on those steep hills.
The San Francisco Cable Cars have three types of brakes.
1 Brake shoes that press on the wheel.s
2 Wooden blocks that press on the rails.
3 Emergency Brake - A steel plate that wedges into the slot.
http://www.cablecarmuseum.org/the-brakes.html
With Cable cars, cables wear is faster and more severe do to the gripping and ungripping of the cable.
One hazzard of the cable car, not present in other cable technologies, is that because of a malfunction the grip does not release the cable. This could be because the cable is frayed, or because the cable has stretched and somehow gotten wrapped around the grip. When this happens the only practicle way to stop the car is to use the emerengcy brake.
I tried to sell my two cents worth, but no one would give me a plug nickel for it.
I don't have a leg to stand on.
My understanding is that those wooden blocks are replaced quite often, too.
An additional safety issue with cable cars is the great amount of inertia present in the cable. If the car is stuck on the cable in an accident, it will continue to drag whatever it hit until the cable is stopped or the car disengaged.
NorthWestMy understanding is that those wooden blocks are replaced quite often, too.
About every three days per the Museum website.
The steel plate emergency brake is a last resort. If used a torch may be needed to cut it out of the slot.
gardendance Please give examples to back up your statement. Where is cable powered "transit" in airports that is not limited to their own track, have switches to meet other cable cars, or have multiple cars running on the same track and multiple cables?
Please give examples to back up your statement. Where is cable powered "transit" in airports that is not limited to their own track, have switches to meet other cable cars, or have multiple cars running on the same track and multiple cables?
The 2 examples that come to mind are Detroit Metro Airport (which has been cited earlier in this thread by someone else) and Minneapolis-St. Paul Airport. Luckily the MSP cable car is outside, so you can see it clearly on Google Earth at:
44°52'56.84"N 93°12'19.81"W
A clearer and more illustrative view is shown in historical image dated 9/15/2013. The reference point is at the switch between the 2 intermediate station platforms. The passing siding and platform for inbound cars is to the upper left (NW), and the platform for the outbound cars is to the lower right. In the 9/2013 image there is a 2 car train almost totally within the patform/canopy area. While the inbound train platform stop is in the passing siding, the outbound train must go thru the siding, before getting to its platform to access the airport concourse. It's more complicated than the Detroit example, where both cars stop at the same time in the intermediate station at the passing siding. That the MSP situation is more complicated is borne out by the fact that they had a collision between cars when they were testing the system.
DSchmitt gardendance Please give examples to back up your statement. Where is cable powered "transit" in airports that is not limited to their own track, have switches to meet other cable cars, or have multiple cars running on the same track and multiple cables? I doubt he can. ...
I doubt he can. ...
See my previous post.
No matter how complicated the system is, unless the cars can be operated independently by operators on the cars, who can attach and detach the car from the cable and operate the brakes as needed, they are not cable cars. They are a different cable powered technology.
Cable powered people mover systems are viable in controlled situations, but the traditional cable car whether run in the street or on controlled access R/W is not. The cable car was developed to replace the horse car on street railways and for use on very steep hills (there were already cable assists for horse cars on some steep hills). There appeared to be nothing better at the time. Both motor and engine powerered vehicles were in very early stages of developement, not as well known as cable power. Some street railways used small steam locomotives but they were noisy, dirty, often accused of scaring the horses and not popular with the public. The cable car was an advancement on existing mature technolody increasing its flexability and allowing it to be used mixed with other traffic on the streets. If they did not already exist today, cable cars systems (as opposed to cable powered people movers, which as stated before are not the same thing) would not be built because they are not economical and also because they would probably be banned in the USA due to the hazards. They only suvive in San Francisco as a historic artifact and tourist attraction.
CSSHEGEWISCHA cable railway sounds similar to the system in place on Brazil's Sao Paulo-Santos line before it was converted to a cog-and-rack system.
Which one? There were two very different systems, one dating from the opening of the line in the 1860s, and another on the new line built around the turn of the century.
The newer system is probably the one of interest. Although it worked like a funicular ('up' trains balancing 'down' trains, and I believe gantleted track above and below a passing siding halfway down each plane), the 'locobreque' system clearly involved a grip, which was released so a train could proceed under its own power across each bankhead to the next 'endless-cable' run.
The principal difference, I think, between this and a traditional cable system is that the Brazilian system stopped and started its cable for each pair of trains, and did not keep it running continuously as the transit systems we were discussing did. So the presence or absence of a discrete grip is not exactly the discriminating factor -- the way the cable is used for traction is.
It is difficult to imagine where a modern system would go to the trouble of providing a loop of engine-driven cable and also an arrangement of mechanical grips (presumably automatic) that would engage and release from that cable. The same could be said for a system that would work like PRT, with individual motors in each car, for those areas of a system where individually-routed or -scheduled cars were wanted, but either assembling these cars into trains that grip a moving cable, or 'automatically' attach to a cable at inherently fixed short headway for longer stretches.
Automotive engineers would love the latter system, but it would work only as long as all the grips were kept perfectly maintained. Let one fail, either in engagement or in release... and the results will be interesting. (There are other problems behind that one, too... but you'd have to be awfully wedded to the overall cockamamie concept to stick with it long enough to start addressing those...)
I am frankly amazed that this thread has gotten to 67 posts and there is still contention about what kinds of cable system are being discussed.
WizlishI am frankly amazed that this thread has gotten to 67 posts and there is still contention about what kinds of cable system are being discussed.
“Never wrestle with pigs. You both get dirty and the pig likes it.” ― George Bernard Shaw
I don't think I'm the pig, but don't know for sure. Maybe I'm biased
Seriously a lot of good information about cable propulsion has been presented in this thread
I believe there is a place in Wales called Lladudno which might still have cable hauled trams. I also believe that the las tcity in the US to abandon it's cablw cars altogether was SEattle. Wouldn't be grand if we still had two cites still running cable cars?
Well, thanks to a decptive election ad campaign in the 1950s, the voters were fooled into voting for a reduced system in San Francisco. The California Street line was cut back to Van Ness, leaving the section from there west to Fillmore with no transit service at all. The Washington-Jackson line was abandoned outriright and so was the O'Farrel, Jones and Hyde route along with the Jones Street Shuttle.
No, the Mount Adams Incline was abandoned in 1948.
I should have written "companies" not "lines". (although Hilton calls each company a "line") There were 62 cable companies in 28 cities. (Brooklyn listed seperately in the list is a borough of New York)
Until il the great merger of 1899, Brooklyn was a separate city from New York, which was Manhattan and part of the Bronx mainland.
MidlandMike,
I googled the Detroit Airport and don't see how that's any different from a regular funicular such as those in Pittsburg with 1 cable, 2 cars permanently attached to the cable, and gauntlet track.
Since you say Minneapolis-St. Paul Airport had a collision I'm going to guess it is indeed more complicated.
Patrick Boylan
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Gardendance, I haven't been to Pittsburgh Airport since Allegheny Air got gobbled up, so I don't know enough to compare. Another poster in this thread has confirmed that Detroit's cable system has switches. There are only 2 "cars" (they may be articulated?).
I thought MSP might have had more cars, but when I looked again at the air photo view, it appears they just have the 2 multi-cars sets.
As I thought I indicated before, I only cite these examples to show that the cable car is not totally dead, and that a city cable car would need multiple cars and detachable grips, and an attendant for safety. Nevertheless, the same companies that supply the airport cable systems, also supply aerial trams with detachable grips, multiple trams/gondolas, multi stops, etc, so they would have the expertise to develope a modern cable car system, if some one would pay them.
I didn't say Pittsburg airport. I said funicular such as those in Pittsburg, and I meant the Mt Washington and Duquesne inclines.
I agree that someone can build anything if someone's willing to pay them. I don't believe anyone's going to pay anyone to build a cable driven streetcar.
gardendanceSince you say Minneapolis-St. Paul Airport had a collision I'm going to guess it is indeed more complicated.
It's not. People misunderstood the semantics of 'cars' having a 'collision'. Two cars on a cable, collision was into a buffer and then the terminal wall.
Here is a .pdf download that tells the story.
And you thought BART had incompetent engineers!
gardendance I didn't say Pittsburg airport. I said funicular such as those in Pittsburg, and I meant the Mt Washington and Duquesne inclines. I agree that someone can build anything if someone's willing to pay them. I don't believe anyone's going to pay anyone to build a cable driven streetcar.
Except in Dundee, New Zealand, as part of an historic recreation.
daveklepperExcept in Dundee, New Zealand, as part of an historic recreation.
I think you mean Wellington. Here is a .pdf with some information.
The original cable system is notable for having the grip engage to pull a car DOWNHILL. The two cars were also cabled together in funicular style. I have been looking for a description of the 'new' system but have not found it yet.
I do not know the details of the original Wellington technology, but it probably was a genuine cable-car line with grips. The present system is clearly a regular funicular, with symmetrical station stops, on private right-of-way. It is both a funicular for tourists, and like the Pittsburgh funiculars, also part of the transit system for commuters, etc. The Haifa Carmelit, Haifa's subway, is also a funicular as far as technology.
Dundee's main hill-climbing street had a cable-car line with cars very much like those in SF, using grips and a continiuous cable. There has been some local promotion of the idea of restoring it. It was completely on-street. Of course, it too could be restored as a funicular rather than as a grip-cable-car line.
Stutgart has a streetcar funicular. Not a cable-car line but a funicular operating on a street. So does one of the Swiss cities, I foget whether it is Zurich, Bern, or Basel. These both have rout numbers as part of the transit system.
In general all these funiculars have either single track with one passing siding or guatlet track with one passing siding. One car always is on the left and one always on the right whether ascending or descending. Typical also is single track below the siding and gauntlet above, the gauntlet above keeping the two cables apart. But the Haifa subway is single-track with the passing siding between the third and fourth of the six stations. If single-track, one car has wheel flanges on the outside and one on the inside, thus assuring it takes the correct track at the passing siding without needing to move switch-points. There are exceptions with comoputer-controlled switches.
WizlishIt's not. People misunderstood the semantics of 'cars' having a 'collision'. Two cars on a cable, collision was into a buffer and then the terminal wall. Here is a .pdf download that tells the story. And you thought BART had incompetent engineers!
And the "cars" do not have brakes. Stopping the cable to stops the "car". A cable car attaches and detaches from a continously moving cable, using brakes on the car to stop.
daveklepperI do not know the details of the original Wellington technology, but it probably was a genuine cable-car line with grips.
If I understood the 'technical paper' correctly, the original system was an unpowered funicular -- two cars on opposite sides of a 'dummy' pulley wheel, operating a bit like a horizontal dumbwaiter. At least one of the cars had a water tank, which was filled when that car was the 'descending' car, and this pulled a loaded car 'uphill' as it went down.
The grip system replaces the water with a separate driving cable; as I understood it, the cars retain the 'passive' funicular cabling, and the grip car engages this driving cable going downward (substituting as it were for the full water tank).
Or at least that is what I understood from the material I was reading...
WizlishThe grip system replaces the water with a separate driving cable; as I understood it, the cars retain the 'passive' funicular cabling, and the grip car engages this driving cable going downward (substituting as it were for the full water tank). Or at least that is what I understood from the material I was reading...
Yery interesting. From: http://www.wellingtoncablecar.co.nz/history/
"The original cable car system remained in service and largely unchanged until 1978 when it was replaced with the current Swiss designed system which is a hybrid cable car and funicular."
Anyone find a link to info about this hybris system?
gardendance ... I agree that someone can build anything if someone's willing to pay them. I don't believe anyone's going to pay anyone to build a cable driven streetcar.
...
As has been pointed out, one city has considered re-establishing a cable car system as a historical recreation.
Also, some city planners have decided that overhead trolley wires, poles, and hardware are undesirable, especially in historic areas, and have sought out alternatives. Besides battery powered/augmented trolleys, 2 "live" systems have been created. One used an induction line between the rails, but is considered inefficient. The other (also reported recently in NewsWire IIRC) is a Lionel-like third rail that only becomes live under the trolley. No one will ever be electrocuted for stepping this 3rd rail if it works flawlessly, which is to say that some one will eventually be electrocuted. At that point, it wouldn't be a stretch for companies which are already selling simple people-mover type cable systems and detachable grip aerial trams, to make the next step into street cable cars.
Although I enjoyed th San Fran. cable cars, I am not really a cable car fan or advocate, and I have doubts about the practicality of building a new cable car line, but I still would never say that one will not be built.
The Alstom "Lionel-type" power-only-under-railcar system is a fail-safe sysem. If anything goes wrong, power does not appear. So I doubt that anyone will be electrocuted by this system, ever. It has been applied for the entire Dubai light rail system. This system has reserved lanes in streets, tunnels, elevated structure, and regular PRofW. It has enclosed and air-conditioned stations with platform doors matching car doors. They really spared no expense. The cars are Alstom Citadus 402, seven section four-truck (sixteen wheels) not multiple unit and no overhead wire. The only time space is shared with regular traffic is at grade crossings/street intersections. The signal system and grade-crossing protection is typical of heavy rapid transit, not light rail, and there is some automation of operation to insure alignment of railcar doors with station doors.
daveklepperThe Alstom "Lionel-type" power-only-under-railcar system is a fail-safe sysem. If anything goes wrong, power does not appear. So I doubt that anyone will be electrocuted by this system, ever. It has been applied for the entire Dubai light rail system.
Doesn't rain much in Dubai, does it? I have read that when APS was installed in France, where it does rain more frequently, problems developed. Personally, I think stud contact, as practiced by GE back around the turn of the 20th Century, is a more sensible system, even if it does require a longer and more complex "pick-up" arrangement under each car. There was an account of it in Burch's 1911 book on the use of electricity for rail traction.
And then there is STREAM, which is like a near-continuous version of stud contact -- this page (not in English but with a graphic) shows how the arrangement works. I have my worries about just how safe this system will be long-term. One of the engineers on here might comment on how any 'sticking' of the magnetically lifted element is prevented.
MidlandMike gardendance ... I agree that someone can build anything if someone's willing to pay them. I don't believe anyone's going to pay anyone to build a cable driven streetcar.
This is a relatively long thread. Please be considerate and tell us who pointed it out, what's the city, and how close to reality did their consideration get?
MidlandMike Also, some city planners have decided that overhead trolley wires, poles, and hardware are undesirable, especially in historic areas, and have sought out alternatives... it wouldn't be a stretch for companies which are already selling simple people-mover type cable systems and detachable grip aerial trams, to make the next step into street cable cars.
Also, some city planners have decided that overhead trolley wires, poles, and hardware are undesirable, especially in historic areas, and have sought out alternatives...
it wouldn't be a stretch for companies which are already selling simple people-mover type cable systems and detachable grip aerial trams, to make the next step into street cable cars.
It would be less of a stretch for the city planners to decide that the cost doesn't justify the benefit, and will pick some other way to get streetcars, or maybe even decide to forget rail and use buses.
MidlandMike Although I enjoyed th San Fran. cable cars, I am not really a cable car fan or advocate, and I have doubts about the practicality of building a new cable car line, but I still would never say that one will not be built.
And I don't consider one or two lines to be a comeback.
Again, the only city considering a cable car line is Dundee, New Zealand, and that is for historical recreatioh purposes only.
It does rain in Dubai on occasion. Sand storms are a worse problem, and the Alstom power-under-car-only system does cope with them.
gardendance And I don't consider one or two lines to be a comeback.
In your previous post you said that you didn't believe any cable systems would be paid for (how else would it be built?). I agree that cable will probably never make a significant comeback, but one or two new systems confirms my contention that to say that a new cable car line will NEVER be built, is an overstatement.
Also Daveklepper answered your question about an historical recreation. Your second question about costs of a new cable car system can't be answered until a company bids on it.
I did not state anything, I expressed an opinion and clearly declared it to be opinion. I'll change my opinion as soon as somebody builds a reasonably long lasting cable car line LIKE THE ONES IN SAN FRANCISCO.
Dave Klepper did not completely answer my question. The last part was how close to reality did their consideration get?
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