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South Kensington station's escalator replacement project

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Re: South Kensington station's escalator replacement project

#101

Post by tialaramex »

traceroute66 wrote: post #46
s15624 wrote: post #13

Earlier quoted context omitted.

The majority of the tube network is pretty much already at peak capacity, with trains on the Victoria, Jubilee and Northern being full autonomous with moving block systems as separation distance can now only be maintained through autonomous systems. I think an express service would be wonderful but it would require careful orchestration. I think it might be worth increasing the line speed through signaling upgrades a…

Isn't the problem with automation on the tube less the technology but more the unions ?

The unions don't help but they reflect largely the interest of their members. Who doesn't want constantly improving pay and conditions and no possibility of redundancies? In effect you have to bribe the train union / its members to land automation that they perceive as potentially weakening their future bargaining position. They don't care about notional safety -- or at least no more than most individuals do in practice -- they care about their personal outcomes. One common bribe for drivers is time set aside for "education" that can be done at home and isn't assessed. Say you give drivers 30 minutes per week for this "education", well, now you've got 0.5 hours per driver of driving needed, you can't hire the necessary drivers quickly enough to cover that, so, you pay overtime to cover it. Lo and behold every driver is keen to do the extra overtime. Now your workers are doing the same job for more money, but when asked about it their union can say it's not that you paid more money, it's because you agreed they needed time for appropriate "education" which is quite different and will contribute to improved safety.

My favourite example of how unionised workers whose union invariably presents their preferences as "safety" care little about actual safety was signallers. Historically some mainline rail signallers (same unions) in the UK worked 12 hour shifts at outlying boxes. So you maybe do 3 x 12 hour shifts = 36 hours that's a week's work or take an extra as overtime for 48 hours. Roster maybe a dozen people to work a box and it remains open 24/7. Annoying scientists said, wait a minute, humans don't remain useful and attentive workers for 12 straight hours, especially at night which explains these incidents where a signaller makes a grave error at like 0400 after 10 hours at work. So the safety regulator wants to limit shifts to 8 hours like for air traffic. The unions are apoplectic because if you're a member working a mixture of 3x12 and 4x12 and now they want you to work 5x8 that's up to two days per week extra. Suddenly railway safety vanishes as a concern...

It is possible to make gradual progress. When I was born there were still guards on tube trains. Why? Well there had always been guards on tube trains. Today of course London Underground does not have guards. It just took a long time to make it happen, with I believe the Northern Line being last to stop having guards.

Re: South Kensington station's escalator replacement project

#102

Post by SideburnsOfDoom »

FabHK wrote: post #31

The article didn't mention the length of the escalator? Longest ones apparently are to be found at the Park Pobedy metro station in Moscow at 126 m, and in St Petersburg. Longest escalator system, and my favourite, is the Hong Kong Central–Mid-Levels escalator, at 790 m (2,600 ft). Many people's commute to work. https://en.wikipedia.org/wiki/Central–Mid-Levels_escalator Escalator accidents: 1982 Moscow https://en.wik…

The longest single-span Escalators on the London Underground, are at Angel Station.

https://www.youtube.com/watch?v=fFqQOlYE4EE

"the longest escalators on the Underground network, and the fourth-longest escalators in Western Europe"

https://en.wikipedia.org/wiki/Angel_tube_station

Angel is much deeper than Kensington, so the Kensington ones won't be that long.

Re: South Kensington station's escalator replacement project

#103

Post by anticensor »

willyt wrote: post #70
traceroute66 wrote: post #6

To be honest, for me the most interesting part of the blog post was this one-liner "for an unbuilt high-speed District line service between South Kensington and Mansion House with just one stop at Embankment.". As one of the millions who at some historical point in their lives has had to suffer the District line commute, the above is a thought I used to have regularly whilst stuck sniffing someone's armpit on the Dis…

The tube has shorter times between trains than the New York subway. For example, Picadilly/Central/Victoria line trains run at <120 second headways on the central section. You couldn't control the gaps between trains precisely enough to demerge and remerge trains once you account for random factor of passenger loading and unloading and changing gaps between trains as they accelerate and decelerate between stations. B…

> random factor of passenger loading and unloading and changing gaps between trains as they accelerate and decelerate between stations.

Solution: Never arrive early, never depart late, and keep the stopping durations fixed, at the longest time possible (which is one quarter the time between the two closest neighbouring stations).

Re: South Kensington station's escalator replacement project

#104

Post by adwww »

noneeeed wrote: post #42
adwww wrote: post #40

Earlier quoted context omitted.

Could you have odd / even trains that miss stops?

Yes, you can do things like that, but that ends up with you having two different sets of stations that are not easy to get between. The normal pattern is express trains that stop a few times with stoppers that "fill-in" between, but there will be different patterns of stopping to try and optimise for different groups of travelers. Scheduling/timetabling is a wickedly hard problem, especially in a system like a railwa…

Yeah I've previously worked on some constraint programming tasks and it was fun but mind-boggling.

Re: South Kensington station's escalator replacement project

#105

Post by Smaug123 »

anticensor wrote: post #103
willyt wrote: post #70

Earlier quoted context omitted.

The tube has shorter times between trains than the New York subway. For example, Picadilly/Central/Victoria line trains run at <120 second headways on the central section. You couldn't control the gaps between trains precisely enough to demerge and remerge trains once you account for random factor of passenger loading and unloading and changing gaps between trains as they accelerate and decelerate between stations. B…

> random factor of passenger loading and unloading and changing gaps between trains as they accelerate and decelerate between stations. Solution: Never arrive early, never depart late, and keep the stopping durations fixed, at the longest time possible (which is one quarter the time between the two closest neighbouring stations).

That's not actually a solution. What do you do when someone holds the door open? Unless you have someone next to each door ready to boot such people out of the train, you simply can't stop yourself departing late.

Re: South Kensington station's escalator replacement project

#106

Post by [deleted] »

Smaug123 wrote: post #105
anticensor wrote: post #103

Earlier quoted context omitted.

> random factor of passenger loading and unloading and changing gaps between trains as they accelerate and decelerate between stations. Solution: Never arrive early, never depart late, and keep the stopping durations fixed, at the longest time possible (which is one quarter the time between the two closest neighbouring stations).

That's not actually a solution. What do you do when someone holds the door open? Unless you have someone next to each door ready to boot such people out of the train, you simply can't stop yourself departing late.

[deleted]

Re: South Kensington station's escalator replacement project

#107

Post by noneeeed »

adwww wrote: post #104
noneeeed wrote: post #42

Earlier quoted context omitted.

Yes, you can do things like that, but that ends up with you having two different sets of stations that are not easy to get between. The normal pattern is express trains that stop a few times with stoppers that "fill-in" between, but there will be different patterns of stopping to try and optimise for different groups of travelers. Scheduling/timetabling is a wickedly hard problem, especially in a system like a railwa…

Yeah I've previously worked on some constraint programming tasks and it was fun but mind-boggling.

It was one of my favourite course at uni, I'd love to get back into doing something like that at some point.

Re: South Kensington station's escalator replacement project

#108

Post by adwww »

noneeeed wrote: post #107
adwww wrote: post #104

Earlier quoted context omitted.

Yeah I've previously worked on some constraint programming tasks and it was fun but mind-boggling.

It was one of my favourite course at uni, I'd love to get back into doing something like that at some point.

I didn't use them in the end, but the Google OR-Tools is a pretty amazing resource for this. I don't have a CS degree, so just seeing the names of the algorithms was helpful ha.

https://developers.google.com/optimization/routing

Re: South Kensington station's escalator replacement project

#109

Post by anticensor »

Smaug123 wrote: post #105
anticensor wrote: post #103

Earlier quoted context omitted.

> random factor of passenger loading and unloading and changing gaps between trains as they accelerate and decelerate between stations. Solution: Never arrive early, never depart late, and keep the stopping durations fixed, at the longest time possible (which is one quarter the time between the two closest neighbouring stations).

That's not actually a solution. What do you do when someone holds the door open? Unless you have someone next to each door ready to boot such people out of the train, you simply can't stop yourself departing late.

Have station doors, and slam shut them before the train doors close.

Re: South Kensington station's escalator replacement project

#110

Post by m4rtink »

noneeeed wrote: post #22
m4rtink wrote: post #19

Earlier quoted context omitted.

How did the heavy industry influence the water table ? I guess they used a lot of water from wells, lowering the water table ?

Yep, basically. Water use is one of those hidden effects of a lot of industrial processes, whether it's used as a coolant or a solvant for processes it often takes a ridiculous amount to produce many goods. In the past the water would be pumped up from boreholes (London sits on an artesian basin), and was then discharged into the Thames (directly or through the waste water system). This happens a lot less now, becaus…

Oh, interesting! I guess the local hydrology here in Czech Republic is different as AFAIK all the old industry around here used to take (a lot!) of water from the local rivers, artificial mill water channels, etc. Haven't heard about them ever using wells in any significant way.
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