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How we slowed the subway down

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Re: How we slowed the subway down

#11

Post by vosper »

gruturo wrote: post #7
hristov wrote: post #5

Earlier quoted context omitted.

"Sure you save some lives but how many will be late!" I do not like this math. For example the accident may not be once per century. And it is good for the bureaucracy to be risk adverse if it comes to my life. The answer is that they should improve the technology so that the system is safe and faster.

If OP's subway carried 80k people per day (and I guess this could be conservative), and they are all delayed 15 minutes, the overall wasted time equals 1 lifetime per month. I'm all for improving the technology, but in the meantime the math should absolutely be done, at least to ensure the temporary fix isn't worse than the problem.

Is it necessarily wasted, though? If the subway is tedious and unpleasant, then sure. But if I get a seat and I get 15 more minutes reading or staring out the window, then I’m probably not calling that a complete waste.

Re: How we slowed the subway down

#12

Post by hristov »

It is actually bonkers that in this day and age the NYC subway cannot install accurate speed gauges on their trains. You can get an accurate bike speedometer for $20 on amazon, but the NYC subway cannot provide an accurate speedometer for train carrying a couple of hundred people. It is true that trains require more rigorous standards, but it is not a difficult problem. For example you can put a sensor on the electrical motor that will accurately measure motor position. This will allow you to derive speed, as subway motors are directly geared to the wheels at a single unchanging gear ratio.

Same thing for stationary speed sensors in the signaling system. It is maddening that they have to time a train over a distance of 50 feet and use an electro-mechanical timing mechanism. Which has to be regularly maintained and it tends to give wrong readings when not properly maintained, etc. Why not get an instantaneous speed reading with lasers? Those have worked for police officers for 40 years now. Or infrared. Or if you have to time a train over a distance time it with a purely electronic system over a distance of a couple of inches. There are definitely electronics fast enough to do that nowadays. And you can get a purely electronic system that requires zero or almost zero maintenance.

Re: How we slowed the subway down

#13

Post by maria2 »

jraph wrote: post #9
maria2 wrote: post #6

Earlier quoted context omitted.

Many lifetimes of time are being wasted every day to save < 10 lives every century.

Life can't be reduced to (productive) time like this. At least I find this take very sad.

Why do you find it sad? Everything has a cost. There are plenty of things that harm people every single day that we tolerate readily. For example, 91 lumberjacks died last year. There are way fewer employed lumberjacks than there are subway riders.

Re: How we slowed the subway down

#14

Post by nullc »

jraph wrote: post #9
maria2 wrote: post #6

Earlier quoted context omitted.

Many lifetimes of time are being wasted every day to save < 10 lives every century.

Life can't be reduced to (productive) time like this. At least I find this take very sad.

You don't necessarily need to make that comparison: If you make the trains too slow many people will drive instead which is radically more likely to kill them than the train.

So you can still find that there is a speed risk tradeoff the minimizes death which is not the same as minimizing the train risk.

Worse for NY's problems is that in that decision people are probably using something like the 95-percentile trip time as the criteria: It doesn't help them if the train is fast on average since they need to schedule for the worst-likely case. The fact that the crews are playing roulette with an kafkaesque speed limiter system and risking disciplinary action should they anger it essentially guarantees that the times will be both slow and highly inconsistent.

Re: How we slowed the subway down

#15

Post by jraph »

nullc wrote: post #14
jraph wrote: post #9

Earlier quoted context omitted.

Life can't be reduced to (productive) time like this. At least I find this take very sad.

You don't necessarily need to make that comparison: If you make the trains too slow many people will drive instead which is radically more likely to kill them than the train. So you can still find that there is a speed risk tradeoff the minimizes death which is not the same as minimizing the train risk. Worse for NY's problems is that in that decision people are probably using something like the 95-percentile trip ti…

Indeed fully receptive to this argument.

Re: How we slowed the subway down

#16

Post by poslathian »

dzdt wrote: post #3

After an operator-error derailment on the commuter rail line I frequently ride, the response of the NTSB was to require the railroad de-prioritize on-time performance and increase schedule times. As a frequent rider on the route I would much rather have my 15 minutes per day back and risk a once-per-century fatal accident. But the risk-averse bureaucracy we've built doesn't make such calculations with a balance like…

I often wonder how we might estimate how much of the surplus created by economic growth and technology has been hoovered up by “alarp” in its many forms. I’m scared of the answer, and of the people who wouldn’t see a problem with it.

Re: How we slowed the subway down

#17

Post by Retric »

gruturo wrote: post #7
hristov wrote: post #5

Earlier quoted context omitted.

"Sure you save some lives but how many will be late!" I do not like this math. For example the accident may not be once per century. And it is good for the bureaucracy to be risk adverse if it comes to my life. The answer is that they should improve the technology so that the system is safe and faster.

If OP's subway carried 80k people per day (and I guess this could be conservative), and they are all delayed 15 minutes, the overall wasted time equals 1 lifetime per month. I'm all for improving the technology, but in the meantime the math should absolutely be done, at least to ensure the temporary fix isn't worse than the problem.

There are feedback mechanisms here which shift where people live and work in response to changes in transportation times. Which means you can’t simply extrapolate like that over time.

Re: How we slowed the subway down

#18

Post by quotemstr »

hristov wrote: post #5
dzdt wrote: post #3

After an operator-error derailment on the commuter rail line I frequently ride, the response of the NTSB was to require the railroad de-prioritize on-time performance and increase schedule times. As a frequent rider on the route I would much rather have my 15 minutes per day back and risk a once-per-century fatal accident. But the risk-averse bureaucracy we've built doesn't make such calculations with a balance like…

"Sure you save some lives but how many will be late!" I do not like this math. For example the accident may not be once per century. And it is good for the bureaucracy to be risk adverse if it comes to my life. The answer is that they should improve the technology so that the system is safe and faster.

> I do not like this math

Many policy difficulties arise from unwillingness to trade-offs between "sacred" and non-"sacred" values. It's easy to say that just one life is worth an arbitrary amount of non-fatal inconvenience to an arbitrary number of people. It's the cheap, easy platitude anyone can summon in a meeting. It feels good to say. Simple. Strong. Righteous.

But the world doesn't work this way. Mere life does not, in fact, have infinite, overriding value. Infrastructure engineering is not a morality play. It's a complex set of trade-offs, some involving safety. In a big system like public transit, as crass as it might be to say explicitly, the optimal number of deaths is seldom zero. Safety and utility are not, as the moralists might insist, incommensurable. They in fact exist on the same plane, and to build things that are effective and efficient, we need to trade them off against each other. Failure to do so leads to cowardly paralysis.

In other words: yes, we absolutely should accept some statistical nonzero risk of injury to save time or money in the overwhelmingly common case, because these things matter.

Re: How we slowed the subway down

#19

Post by joe_the_user »

dzdt wrote: post #3

After an operator-error derailment on the commuter rail line I frequently ride, the response of the NTSB was to require the railroad de-prioritize on-time performance and increase schedule times. As a frequent rider on the route I would much rather have my 15 minutes per day back and risk a once-per-century fatal accident. But the risk-averse bureaucracy we've built doesn't make such calculations with a balance like…

A bureaucracy can't ignore the possibility of a deadly crash. But they chose the slow-down instead of spending the money needed for safety. Which is despicable imo. But there is the quandary that they know a modernization project could be a disaster just all American public transit projects tend to be disasters.

Re: How we slowed the subway down

#20

Post by quotemstr »

jraph wrote: post #9
maria2 wrote: post #6

Earlier quoted context omitted.

Many lifetimes of time are being wasted every day to save < 10 lives every century.

Life can't be reduced to (productive) time like this. At least I find this take very sad.

> Life can't be reduced to (productive) time like this

Yes it can, and it's essential that we do it, because the alternative is a ruinous level of risk aversion.

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