Why does it take so long to mend an escalator? (2002)(lrb.co.uk)
lrb.co.uk
Why does it take so long to mend an escalator? (2002)
https://www.lrb.co.uk/v24/n05/peter-campbell/why-does-it-take-so-long-to-mend-an-escalator
91 comments
As an automotive engine mechanic, ive always been fascinated by large building equipment like elevators and escalators.
That having been said, most of the time when large ubiquitous equipment requires periodic maintenance at scheduled intervals, you have more safety involved. large multistory escalators and elevators have numerous moving parts and circuits to lock out/tag out to ensure equipment service is performed safely. The result of a rush-job is always a gruesome headline on the local news.
Theres also extensive testing. Overload/overtorque systems have to be tested, fail-safe certification has to take place, and the device has to run for a given time before its entered back into service. In my job, I wouldnt think to return a heavy truck to a customer before driving it on both city and highway streets to confirm everything I've worked on performs as expected.
That having been said, most of the time when large ubiquitous equipment requires periodic maintenance at scheduled intervals, you have more safety involved. large multistory escalators and elevators have numerous moving parts and circuits to lock out/tag out to ensure equipment service is performed safely. The result of a rush-job is always a gruesome headline on the local news.
Theres also extensive testing. Overload/overtorque systems have to be tested, fail-safe certification has to take place, and the device has to run for a given time before its entered back into service. In my job, I wouldnt think to return a heavy truck to a customer before driving it on both city and highway streets to confirm everything I've worked on performs as expected.
I can vouch for the testing and safety overhead when compared to what the layman might imagine. A friend of mine designs the ticket barriers for the London Underground, among other customers, and the work that goes into ensuring the safety of those autonatic saloon-door style gates is enormous - you can just imagine what a poorly designed or faulty one might do to, I dont know, a pregnant person. It’s definitely a case of the 80:20 rule applying to the design vs the finessing and safety.
>The result of a rush-job is always a gruesome headline on the local news.
The opposite. 99x/100 rushing things turns out fine. It's just a small fraction of the time you get a near miss or an actual injury. We just happen to live in a society where those risks aren't tolerated. Elsewhere in the world those risks are tolerated. That's part of why so much manufacturing has moved overseas. When you don't have to spend an hour locking out a conveyor system to spend 10min replacing a part you can pass those savings down to your customers and undercut the competition.
The opposite. 99x/100 rushing things turns out fine. It's just a small fraction of the time you get a near miss or an actual injury. We just happen to live in a society where those risks aren't tolerated. Elsewhere in the world those risks are tolerated. That's part of why so much manufacturing has moved overseas. When you don't have to spend an hour locking out a conveyor system to spend 10min replacing a part you can pass those savings down to your customers and undercut the competition.
Hence the term 'normalization of deviance' [0] (where small problems occur repeatedly and people become habituated to them because nothing really bad ever happens). When the really bad thing happens, then you get the gruesome headlines. Examples the are O-ring burn-through events that preceded the Challenger disaster [1] (7 astronauts, dead), and the 'smoulders' that preceded the Kings Cross underground railway fire [2] (31 people. Dead.)
[0] https://en.wikipedia.org/wiki/Diane_Vaughan
[1] https://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disas...
[2] https://en.wikipedia.org/wiki/King%27s_Cross_fire
[0] https://en.wikipedia.org/wiki/Diane_Vaughan
[1] https://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disas...
[2] https://en.wikipedia.org/wiki/King%27s_Cross_fire
>It's just a small fraction of the time you get a near miss or an actual injury.
We're taught to value the entire lifecycle of our work, at least in my field. For example, rushing to finish a steering maintenance on a large tanker truck could mean your friend gets his thumbs crushed under a pry bar, or it could mean hundreds of fatalities as the poor job you did caused the tanker to collide with a shopping center.
A missing cotter pin or a failed motor ground could easily injure dozens, or even kill them, on a large enough escalator.
We're taught to value the entire lifecycle of our work, at least in my field. For example, rushing to finish a steering maintenance on a large tanker truck could mean your friend gets his thumbs crushed under a pry bar, or it could mean hundreds of fatalities as the poor job you did caused the tanker to collide with a shopping center.
A missing cotter pin or a failed motor ground could easily injure dozens, or even kill them, on a large enough escalator.
>, or it could mean hundreds of fatalities as the poor job you did caused the tanker to collide with a shopping center.
This is exactly what I'm talking about. The vast majority of the time mechanical failure results in the vehicle coming to a stop on the shoulder without anything spectacular happening. Think about all the trailer blowouts where the only damage was to the underwear of whoever was nearby. We do things (like install cotter pins, on steering, not in tires, or not intentionally at least) to prevent those sorts of failures because there's a small chance of something spectacularly bad happening (and because downtime is $$ and if you're broken down on the side of the road the DOT vultures will turn up out of nowhere and find a reason to make your downtime even more $$).
This is exactly what I'm talking about. The vast majority of the time mechanical failure results in the vehicle coming to a stop on the shoulder without anything spectacular happening. Think about all the trailer blowouts where the only damage was to the underwear of whoever was nearby. We do things (like install cotter pins, on steering, not in tires, or not intentionally at least) to prevent those sorts of failures because there's a small chance of something spectacularly bad happening (and because downtime is $$ and if you're broken down on the side of the road the DOT vultures will turn up out of nowhere and find a reason to make your downtime even more $$).
I think that's the cognitive bias called the Optimism Bias.
https://psychonline.eku.edu/insidelook/%E2%80%9Cit-won%E2%80...
https://psychonline.eku.edu/insidelook/%E2%80%9Cit-won%E2%80...
My point still stands. Most corner cutting (is it even corner cutting if the safety requirement isn't there in the first place?) will turn out fine unless you cut the same corner every day of your life or cut a ton of corners at once. If that weren't the case every electrician that ever tagged out a breaker with a piece of tape and a note saying to check to make sure X isn't still being worked on would be dead.
Yes, I was agreeing with you... just adding the name to this phenomena.
Well, that depends. Is the escalator located at the Embarcadero BART Station in San Francisco? Are there people shitting on the escalator? Are the escalators designed to take such an abuse? Would you like the maintenance team to do something else or just fix the same escalator each week?
The idea that hobo feces are responsible for BART's escalator problems is really an urban legend. It's the design of the damned thing, combined with statutorily mandated low-bid contracting that keeps them broken. At BART's brand-new Warm Springs station the escalators are all under roofs and there are no homeless people anywhere, and the escalators (which I must again stress are completely new) are constantly out of service. This is despite the fact that nobody uses this station, which sees less than one tenth the passenger traffic as does Embarcadero.
“When work crews pulled open a broken BART escalator at San Francisco's Civic Center Station last month, they found so much human excrement in its works they had to call a hazardous-materials team.“ (July, 2012)
https://m.sfgate.com/bayarea/article/Human-waste-shuts-down-...
On the other hand although the following article mentions human waste multiple times, it seems likely the largest factor is age:
“The escalators had once been very reliable but are now showing their age, Lemon said. The Dublin/Pleasanton escalator, on the job since 1997, and the Millbrae escalator, in service since 2003, are both closing in on 20 years, which means it’s time for an overhaul, Lemon said.“
https://www.sfchronicle.com/bayarea/article/A-breakdown-of-B...
On the other hand although the following article mentions human waste multiple times, it seems likely the largest factor is age:
“The escalators had once been very reliable but are now showing their age, Lemon said. The Dublin/Pleasanton escalator, on the job since 1997, and the Millbrae escalator, in service since 2003, are both closing in on 20 years, which means it’s time for an overhaul, Lemon said.“
https://www.sfchronicle.com/bayarea/article/A-breakdown-of-B...
I'm not denying the fact that the homeless crap on the BART stations. What I'm saying, and what the data from the new stations proves, is that it's not a factor and neither is age, nor exposure to rain. The new ones in the middle of nowhere with no rain are still unreliable, and there's no significant difference in available between the paid area and street escalators which you would expect to be different if transient excrement was the cause.
The article [1] seems to provide data that disagrees, that the affected escalators have higher failure rates. What do you think is the motivation for these experts providing incorrect information?
1. https://www.sfchronicle.com/bayarea/article/A-breakdown-of-B...
1. https://www.sfchronicle.com/bayarea/article/A-breakdown-of-B...
That analysis commits a variety of errors. For example, they rank Warm Springs as the most reliable with “only” 5 days of downtime in the last two years. Unfortunately at that time the station had only been open for 60 days.
For comparison, on London Underground the escalators are refurbished every 20 years, and replaced every 40 years.
https://tfl.gov.uk/campaign/tube-improvements/behind-the-sce...
https://tfl.gov.uk/campaign/tube-improvements/behind-the-sce...
A hazmat team of 6 in bunny suits arrived each morning for the Hamilton VTA light rail stop in San Jose when I lived there.
That stop has an outdoors elevator, and somebody was wiping shit all over the keypad daily. So reality is even more vile than any urban legend.
That stop has an outdoors elevator, and somebody was wiping shit all over the keypad daily. So reality is even more vile than any urban legend.
At what point do you just station an officer nearby, lying in wait, that will arrest that person on the spot? There has to be some criminal law against this. And as there is not an infinite supply of shit-smearing persons, it would stop soon.
Why assume people are just shit-smearing for "shit and giggles"? As far as I understand it, it's mostly homeless people who end up "doing their business there", due to a lack of better options.
Just fining them, when they ain't got a whole lot of alternatives, sounds like a rather mean, and inefficient, thing to do. They probably can't pay the fine anyway, but they still gonna have the very same bodily urges. So that whole exercise would only have generated some useless bureaucracy, without actually having changed anything about the problem.
A much smarter solution would be to offer homeless people an actual place to do their business, instead of trying to "police away" fundamental societal problems like poverty and homelessness.
Just fining them, when they ain't got a whole lot of alternatives, sounds like a rather mean, and inefficient, thing to do. They probably can't pay the fine anyway, but they still gonna have the very same bodily urges. So that whole exercise would only have generated some useless bureaucracy, without actually having changed anything about the problem.
A much smarter solution would be to offer homeless people an actual place to do their business, instead of trying to "police away" fundamental societal problems like poverty and homelessness.
Like if there were a public restroom near that area. It's at a subway terminal, I'm sure other people have "needs" as well. And if a homeless person needs to take a private crap, well, all the better.
The problem with "public restrooms" that have been tried in california is that they just turn into heroin dens and places for prostitutes to do their business. It's a difficult problem that has seen the occasional actual attempt at a solution
"Why would someone shit on an escalator?" seems absurd enough to be the setup for a joke or a Zen koan, but I'm going to ask it anyway. Why would someone shit on an escalator?
BART stations close shortly after midnight, and they are closed by locking gates at the bottom of the stairs and escalators. This means the bottom of the escalator is relatively private, and if you shit on the escalator itself the shit "disappears" when the escalator is turned on.
In a word: drugs.
Expand this comment to pretty much any SF downtown station, frequently, and any other station in the network, less frequently.
[deleted]
ive always thought it would be good to make public items with a built-cleaning loop.
an escalator could have a steam/preasure-washing section that the stairs loop through as a part of the system. it could even work when the escalator is in use.
a publi toilet could have a round seat cover that also spins into the same type of washer in the wall.
an elevator could dock at the bottom level and couple to a drain and water/steam pour in from the top.
the city could provide more restrooms.
clearly these issues can be designed around.
an escalator could have a steam/preasure-washing section that the stairs loop through as a part of the system. it could even work when the escalator is in use.
a publi toilet could have a round seat cover that also spins into the same type of washer in the wall.
an elevator could dock at the bottom level and couple to a drain and water/steam pour in from the top.
the city could provide more restrooms.
clearly these issues can be designed around.
There are in fact self-cleaning public toilets that ranges from "just" washing the seat, bowl and floor to full pressure washing of the entire interior.
Of the Seattle bus tunnel escalators, I can count on one hand the number that permanently smell like day old piss...
But I shouldn’t really have to count them.
But I shouldn’t really have to count them.
But there are only five bus tunnel stops...
Convention Center, Westlake, University, Pioneer Square, International District.
Convention Center, Westlake, University, Pioneer Square, International District.
This is slightly depressing as I've been looking forward to Isaac Asimov's "belts" for some time now. A giant loop of of parallel walkways of graded speeds, continuously operating for city-wide underground transport.
I guess now that they'd have the escalator maintenence issues with steroids.
I guess now that they'd have the escalator maintenence issues with steroids.
They sound like an accessibility nightmare.
Imagine an old person or someone with movement issues not quite making the transition between the slower and high-speed bands. They’d end up as sort of human bowling ball, knocking down other passengers like skittles.
Similar thing happened to me on a crowded escalator at London Bridge tube station. Was about half way up when an old guy in front toppled back onto me. Thankfully I’d noticed he looked unsteady and managed to catch him under his armpits, otherwise we’d all have ended up in a heap at the bottom.
I didn’t have the leverage to get him upright, so we stayed with me holding him until we reached the top. His shoes hit the metal plate at the end and I flipped him to his feet.
We then gave each other a nod and went about our business.
Imagine an old person or someone with movement issues not quite making the transition between the slower and high-speed bands. They’d end up as sort of human bowling ball, knocking down other passengers like skittles.
Similar thing happened to me on a crowded escalator at London Bridge tube station. Was about half way up when an old guy in front toppled back onto me. Thankfully I’d noticed he looked unsteady and managed to catch him under his armpits, otherwise we’d all have ended up in a heap at the bottom.
I didn’t have the leverage to get him upright, so we stayed with me holding him until we reached the top. His shoes hit the metal plate at the end and I flipped him to his feet.
We then gave each other a nod and went about our business.
In the subway tunnels beneath Montparnasse train station in Paris, there's a long stretch of corridor leading from the above-ground train station to the subway. Three moving sidewalk were installed, with one being higher speed, but they were forced to replace it with a normal-speed one, because of complaints and reliability issues.
Source: https://en.wikipedia.org/wiki/Moving_walkway#Trottoir_roulan...
Source: https://en.wikipedia.org/wiki/Moving_walkway#Trottoir_roulan...
Very interesting. I found a video of an express walkway at a Toronto airport which is apparently still in use. It looks quite complex with foot plates which extend as the belt moves faster. I wonder what it's like to use.
https://www.youtube.com/watch?v=GvfF4TeXz7U
https://www.youtube.com/watch?v=GvfF4TeXz7U
Used it last year. It's fun! You have to stand in the right spot though otherwise the plates extend under your feet which while I don't think it's dangerous, does feel a bit sketchy.
The Arthur C Clarke solution is "anisotropic matter" - walkways that are firm in the vertical direction but can flow in the horizontal axes, so that the same moving way can start slowly, accelerate to a high speed, and decelerate at the other end, all without any transitions.
Although, if we're making arguments about accessibility, I'm sure a more prosaic solution could be found that was no less accessible than just walking normally. But in any case, the usual approach is to have a scalable system for the 99% case, and then to provide an alternative that doesn't scale for the 1% who can't use the scalable solution - chairlifts etc.
Although, if we're making arguments about accessibility, I'm sure a more prosaic solution could be found that was no less accessible than just walking normally. But in any case, the usual approach is to have a scalable system for the 99% case, and then to provide an alternative that doesn't scale for the 1% who can't use the scalable solution - chairlifts etc.
> They sound like an accessibility nightmare.
Much like an escalator, really. People with mobility issues can't use them. Many people are afraid of them. They're hard to use safely with children and/or a pram.
I'm all for stairs for everyone who is able, and lifts for everyone who isn't.
Much like an escalator, really. People with mobility issues can't use them. Many people are afraid of them. They're hard to use safely with children and/or a pram.
I'm all for stairs for everyone who is able, and lifts for everyone who isn't.
While at it: trains are so much more convenient.
Walls and roof protect you from excessive heat, excessive cold, wind, rain, snow, and the sound the mechanisms make.
Seats allow you (or people more tired than you) to sit and work, read, or rest, especially when you ride for an hour.
Also, train infrastructure is vastly narrower than such a collection of moving bands, and is readily available for maintenance when no trains are going.
The downside is that trains have to have stations. But the moving band will have to have a "station" all along it.
Walls and roof protect you from excessive heat, excessive cold, wind, rain, snow, and the sound the mechanisms make.
Seats allow you (or people more tired than you) to sit and work, read, or rest, especially when you ride for an hour.
Also, train infrastructure is vastly narrower than such a collection of moving bands, and is readily available for maintenance when no trains are going.
The downside is that trains have to have stations. But the moving band will have to have a "station" all along it.
I liked the belt idea until i read about bubble cars. have a zillion cars with room for 3 people that are constantly circulating around a track, with roll on roll offs all over the place. hit a button, next empty car rolls off and stops for you. hit a button inside for your destination, accelerate back to the main track speed and you're on your way.
it's kind of like a people mover, but has the ability to actually stop, thanks to the split/merge at the stops.
it's kind of like a people mover, but has the ability to actually stop, thanks to the split/merge at the stops.
If there's just one track, will other zillion-1 cars behind my car stop, while it loads me?
no, stops would have real roll on roll offs - you see them in actual train yards, it's hard to find a good picture.
here's the general idea from a video game https://i.imgur.com/7gNHkNP.jpg
ideally multiple cars could pull out of the main track for loading and unloading(in which case you might have to wait a bit for the car in front).
here's the general idea from a video game https://i.imgur.com/7gNHkNP.jpg
ideally multiple cars could pull out of the main track for loading and unloading(in which case you might have to wait a bit for the car in front).
Why not integrate a "bubble car" into building lift/elevator systems? The capsule brings you 20 km from home, switches to the rails within the lift well and zips up, depositing you directly on your floor.
Thirty years ago lots of people were talking about mass transit systems with small individual capsules. According to one of my engineering lecturers at the time, a limitation was that there simply isn't enough room on the ground to have all those capsules loading and unloading people in a CBD with lots of skyscrapers.
Thirty years ago lots of people were talking about mass transit systems with small individual capsules. According to one of my engineering lecturers at the time, a limitation was that there simply isn't enough room on the ground to have all those capsules loading and unloading people in a CBD with lots of skyscrapers.
I think the point about how much space is needed for high density loading and unloading is excellent. if you're willing to slow down the main line in specific areas, you can use a lot more of the siding rail for loading.
I have no doubt your lecturer is far more informed than i will ever be. I will assert that it's not really 1990 any more, and far more employers would be willing for employees to show up and leave at different times. Car congestion alone has made a lot of employers willing to have start time anywhere from 7 to 10. Which might alleviate some of that burden.
I also think, being able to take the whole trip without stopping - even if you occasionally have to go slower in high congestion areas - is much faster overall for each passenger. Which, in my humble opinion is a huge feature.
If the cars are reversible, you can also have Y junctions and stack up loads of cars perpendicular to the main rail, and fill those cars like a normal train.
I have no doubt your lecturer is far more informed than i will ever be. I will assert that it's not really 1990 any more, and far more employers would be willing for employees to show up and leave at different times. Car congestion alone has made a lot of employers willing to have start time anywhere from 7 to 10. Which might alleviate some of that burden.
I also think, being able to take the whole trip without stopping - even if you occasionally have to go slower in high congestion areas - is much faster overall for each passenger. Which, in my humble opinion is a huge feature.
If the cars are reversible, you can also have Y junctions and stack up loads of cars perpendicular to the main rail, and fill those cars like a normal train.
It's not quite as clear cut as you make it sound, imo.
A belt system would run continuously, which means no waiting for the next train, and you don't have to slow down at every intermediate stop, which should improve average speeds.
A belt system would run continuously, which means no waiting for the next train, and you don't have to slow down at every intermediate stop, which should improve average speeds.
At the cost of much decreased capacity, because a lot of the system moves pretty slowly; you cannot make the bands narrower than what it takes to stand with two feet, and likely wider for some safety.
Also, the amount of area and mass to move per passenger grows quite a lot, because most passengers will want to be on the fastest band, and all the gradual bands will be much less occupied.
The system can work reasonably when the moving bands are very lightweight, thin layers moved by a motor without many (or any) moving parts (the way maglev moves). It also should have absurdly low friction: unlike a train, it has a lot of contact surface.
To say nothing about turns.
Not that it's impossible, but technology-wise we're totally not there yet to make such a thing practical.
Also, the amount of area and mass to move per passenger grows quite a lot, because most passengers will want to be on the fastest band, and all the gradual bands will be much less occupied.
The system can work reasonably when the moving bands are very lightweight, thin layers moved by a motor without many (or any) moving parts (the way maglev moves). It also should have absurdly low friction: unlike a train, it has a lot of contact surface.
To say nothing about turns.
Not that it's impossible, but technology-wise we're totally not there yet to make such a thing practical.
So have one fast band between "stops", and then large concentric circles of gradually slower bands surrounding each "stop"?
No need for stations next to the moving band. The outer bands move slowly enough that you can step on and off at any point. The center bands could have seats, and you could wall the whole thing in to protect from the weather.
Moving slowly enough for whom to step off? The 90 year old lady with a walker? The toddler? Stephen Hawking in his wheelchair?
How slow is it going to accommodate every single person's movement capacity? How small is the gradient between each belt to allow them to move between belts? How wide does this whole thing end up needing to be?
How slow is it going to accommodate every single person's movement capacity? How small is the gradient between each belt to allow them to move between belts? How wide does this whole thing end up needing to be?
> Moving slowly enough for whom to step off? The 90 year old lady with a walker? The toddler? Stephen Hawking in his wheelchair?
Why not? Don't they use moving floors on airports already? (Also, do toddlers walk alone on the busy streets?)
Here's a design I just sketched in Factorio for a belt system with 3 speed levels, and an entry/exit for moving onto the belt system, and then between speed levels.
https://imgur.com/c51pTnP
(For those who don't know Factorio - the blue belts are the fastest, the yellow ones are the slowest.)
Why not? Don't they use moving floors on airports already? (Also, do toddlers walk alone on the busy streets?)
Here's a design I just sketched in Factorio for a belt system with 3 speed levels, and an entry/exit for moving onto the belt system, and then between speed levels.
https://imgur.com/c51pTnP
(For those who don't know Factorio - the blue belts are the fastest, the yellow ones are the slowest.)
Why not? Don't they use moving floors on airports already?
Yes, but they also have non-moving floors, and they also have -- in the US, at least -- a small fleet of carts, driven by airport staff, that can carry people who have difficulty walking.
Any moving-walkway mass-transit system would have to include accessible alternatives.
Yes, but they also have non-moving floors, and they also have -- in the US, at least -- a small fleet of carts, driven by airport staff, that can carry people who have difficulty walking.
Any moving-walkway mass-transit system would have to include accessible alternatives.
Being underground also protects you from excessive heat, excessive cold, wind, rain, and snow.
Being underground won't protect you from the noise of the mechanisms, but neither do the walls and roof of a train. Being on a train is loud.
Large crowds will cause heat within the system that will likely need to be managed, but -- like the noise -- this is equally true of trains.
How are any of those things an advantage of trains over a system of underground walkways?
Being underground won't protect you from the noise of the mechanisms, but neither do the walls and roof of a train. Being on a train is loud.
Large crowds will cause heat within the system that will likely need to be managed, but -- like the noise -- this is equally true of trains.
How are any of those things an advantage of trains over a system of underground walkways?
I just happen to ride a lot of above-ground trains. E.g. much of the New York City subway goes above ground, sometimes pretty high, in Brooklyn and Queens. Same applies to quite a few cities (e.g. London and Moscow, off the top of my head).
But okay, let's imagine out underground walkway. Since it's underground, you can't walk on and off where you want; you only walk off where there's way up to the ground. This eliminates much of the allure of the system. Now you want to plan ahead and be ready to get off when you're next to the exit. If you missed your exit, you have to move to the next exit, or maybe cross the tunnel and go to the band of the opposite direction, and walk back a bit.
Please notice how the low-speed bands then need to run the whole length of the tunnel, adding little to the carrying capacity: few people want to travel at the speed of walking when traveling at the speed of a train is a few meters across.
If we let only the faster band(s) through the length of the tunnel, and limit the slower bands to the exit areas (pretty long and wide), we'll face the problem of walls: our band is moving fast, and nothing separates it from the walls. So we sort of need inner walls on the band. But they need doors to allow people in and out in the exit areas. And the doors need to be shut when the band is in the tunnel. It starts to look like a... train? Only an endless train with a peculiar way of boarding.
This endless train also has a downside: if anything goes wrong, the whole band/train has to stop, it cannot be re-routed. What if we segment the band into individually routable parts? Only then they'll have to stop at exit areas to allow safe getting on / off them.
Well, we have reinvented the subway.
But okay, let's imagine out underground walkway. Since it's underground, you can't walk on and off where you want; you only walk off where there's way up to the ground. This eliminates much of the allure of the system. Now you want to plan ahead and be ready to get off when you're next to the exit. If you missed your exit, you have to move to the next exit, or maybe cross the tunnel and go to the band of the opposite direction, and walk back a bit.
Please notice how the low-speed bands then need to run the whole length of the tunnel, adding little to the carrying capacity: few people want to travel at the speed of walking when traveling at the speed of a train is a few meters across.
If we let only the faster band(s) through the length of the tunnel, and limit the slower bands to the exit areas (pretty long and wide), we'll face the problem of walls: our band is moving fast, and nothing separates it from the walls. So we sort of need inner walls on the band. But they need doors to allow people in and out in the exit areas. And the doors need to be shut when the band is in the tunnel. It starts to look like a... train? Only an endless train with a peculiar way of boarding.
This endless train also has a downside: if anything goes wrong, the whole band/train has to stop, it cannot be re-routed. What if we segment the band into individually routable parts? Only then they'll have to stop at exit areas to allow safe getting on / off them.
Well, we have reinvented the subway.
What does anything in this "response" have to do with heat, cold, wind, rain, snow, or noise?
Why did you put the word response in quotes?
"I just happen to ride a lot of above-ground trains" implies trains being exposed to wind, rain, snow, cold, and heat. Same would apply directly to passengers if the moving walk bands were above-ground.
To imply that nine_k's non sequitur comment doesn't deserve the term "response", in that it doesn't actually respond to anything I said. Why is it posted under my comment?
https://en.wikipedia.org/wiki/Scare_quotes
https://en.wikipedia.org/wiki/Scare_quotes
>Being underground won't protect you from the noise of the mechanisms, but neither do the walls and roof of a train. Being on a train is loud.
More recent trains can be quite protected from mechanism noises. The line I'm taking more often has received brand-new trains and I usually don't hear the noise.
More recent trains can be quite protected from mechanism noises. The line I'm taking more often has received brand-new trains and I usually don't hear the noise.
Trains aren't (all) loud. I just rode an Amtrak yesterday. It was surprisingly quiet.
Tight curves tend to be loud, as is old track, or track that isn't welded into very long lengths. Locomotives are quieter than having motors on each carriage.
In much of Europe that makes trains quiet, except metro trains with tight curve.
People excluded, I think non -metro trains are usually quieter than cars.
I've only used one train in the US, which ran on jointed (not welded) track so made the 'clickety clack' noise, but presumably that varies and the North East is better.
In much of Europe that makes trains quiet, except metro trains with tight curve.
People excluded, I think non -metro trains are usually quieter than cars.
I've only used one train in the US, which ran on jointed (not welded) track so made the 'clickety clack' noise, but presumably that varies and the North East is better.
I once had the pleasure to use a high speed travelator in Paris going at 8mph, I recall they used several acceleration stages in series before getting on the main section. Also reminded me of the ones portrayed in Asimov's novels. Too bad they shut them down almost a decade ago.
https://www.thetransportpolitic.com/2009/05/21/paris-experim...
https://www.thetransportpolitic.com/2009/05/21/paris-experim...
See also Robert Heinlein's short story The Roads Must Roll
Thanks! I found an audio version/adaptation, will listen later:
https://www.youtube.com/watch?v=XAlagNId3fw
https://www.youtube.com/watch?v=XAlagNId3fw
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They've been roundly made fun of here on HN (and elsewhere) but the current electric scooter + smartphone app deployment that is taking place is about 80% of that vision.
In their early days, escalator's were disruptive in that "elevator operators" were eliminated. I wonder if that contributed to the reluctance to use them at first.
> Stepping onto an escalator is an act of faith. From time to time you see people poised at the top, advised by instinct not to launch themselves onto the river of treads. Riding the moving stairs is an adventure for the toddling young and a challenge to the tottering old. Natural hesitancy puts a limit on throughput.
This seems right, but it's also trivial to fix -- just lengthen the ends of the escalator so there's a flat section to get onto or off from. Nobody hesitates to get on a moving sidewalk.
This seems right, but it's also trivial to fix -- just lengthen the ends of the escalator so there's a flat section to get onto or off from. Nobody hesitates to get on a moving sidewalk.
Thats how escalators are often designed, isn't it?
...no? In my experience, you get something like 1.5 steps of flat space before they start rising/descending. It's not enough to be totally comfortable getting on.
"An escalator can never break: it can only become stairs. You should never see an Escalator Temporarily Out Of Order sign, just Escalator Temporarily Stairs. Sorry for the convenience."
[...] The escalators of the station caused a significant disaster on the Moscow Metro on February 17, 1982, that killed at least eight people. [...]
https://en.wikipedia.org/wiki/Aviamotornaya_(Kalininsko%E2%8...
https://en.wikipedia.org/wiki/Aviamotornaya_(Kalininsko%E2%8...
That accident happened when the escalator was in motion when the mechanical failure occurred, and the brakes had been incorrectly installed. If it had been stopped and brakes correctly applied, the escalator would have functioned fine as stairs.
It's a Mitch Hedberg joke
Yeah that's some fun logic.
This isn't a broken web application sir, it's a static web page that displays important exception information.
This isn't a broken web application sir, it's a static web page that displays important exception information.
Give me a static page with the information I want anyday please
Sure. Whenever you feel the need for one of those, click this link: https://news.ycombinator.com/item?id=17702940
500 Internal Server Error
“The web server is down”
No it’s not, it up and running. See that error page?
No it’s not, it up and running. See that error page?
I know this is a joke, but it is false.
https://youtu.be/fLUppwRShpE?t=11
(Aside: I was about 10 minutes walk away from the location when this happened.)
https://youtu.be/fLUppwRShpE?t=11
(Aside: I was about 10 minutes walk away from the location when this happened.)
Ugh, reminds me of this recent ski lift accident: https://www.youtube.com/watch?v=bzvt0gTAXvA
Even worse: https://www.youtube.com/watch?v=L2X1zEIyWUw
Warning, very disturbing, shows someone dying.
Warning, very disturbing, shows someone dying.
As an exercise machine, it is actually broken when it is moving.
Mitch was obviously unfamiliar with WMATA.
Reminds me of a Blendtec salesman I saw at Costco who had one of his arms amputated at the elbow. The initial reaction was revulsion, especially since he made frequent jokes about losing his arm in a blender accident as he was using his arm stub to push things into the blender. But it was a very effective demo in showing how the Blendtec was so easy to use that it practically ran itself.