South Kensington station's escalator replacement project • Hacker News Board

Re: South Kensington station's escalator replacement project

#61

Post by lbriner » Tue, Aug 17, 2021, 2:21 PM UTC

barneybooroo wrote: post #8

It is amazing how what might seem like fairly routine engineering jobs become completely nightmarish once you do it underground. I used to commute via Goodge Street every day. A few years ago they replaced the four lifts (in twos so that two were still in service) which ultimately took two years. I could never really fathom what it was that specifically slowed that down so much but hey the lift congestion every morni…

Underground does present challenges but there are many reasons why these seemingly straight-forward jobs take time. You need qualified/certified workers, a load of up-front work related to ventilation, noise, structural movement, surveys etc. Some of this can only be done in engineering hours.

You have issues around the lack of space in central london for work vehicles, the need for removal of rubbish which can't block up emergency staircases, exits.

Then add in the challenges of unknown unknowns and needing to be able to revert any change quickly that can't be done to plan so you don't end up with a closed station and you start to get there.

I assume they had to do them 1 at a time to completion as well?

Re: South Kensington station's escalator replacement project

#62

Post by lbriner » Tue, Aug 17, 2021, 2:23 PM UTC

piinbinary wrote: post #51

It's really cool that they can use the train tracks to bring stuff into and out of the station. It seems obvious in retrospect, but that had never occurred to me before.

It's not that "obvious" and is not always used. For a start, the power is often off at night so you need one of the few battery locos. You also need a clear route from the station to the nearest loading/offloading point, which might be several mile away from the station.

A lot of time, materials and tools are simply loaded through the station manually and since you are not allowed to store anything flammable below ground, some of it needs to be taken back out at the end of the shift.

They are not keen to lose station time but sometimes I think they could afford to lose an hour either end when they are doing engineering work in a station. At least in this instance, they needed to close the station which saves so much time.

Re: South Kensington station's escalator replacement project

#63

Post by lbriner » Tue, Aug 17, 2021, 2:26 PM UTC

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…

There are not many/any high-frequency metro systems that can do this on the same rails. At peak times, when you could do with the expresses the most, there can be stopping services 1/2 minutes apart on average, which means non-stoppers are simply not possible.

On regional railways, where the service might be every 30 minutes or longer, it is a different prospect since you can send the stopper out immediately after the express and it gets 30 miuntes to get out of the way.

Re: South Kensington station's escalator replacement project

#64

Post by tomfanning » Tue, Aug 17, 2021, 2:26 PM UTC

bartread wrote: post #55

jaclaz wrote: post #29

Earlier quoted context omitted.

From experience in construction (both open air and underground) the key difference is not about something being underground, but rather with something being "in use" while the building site is doing the whatever work is needed. Particularly when it is something of public use, be it a highway or a railway, the amount of precautions, limitations and safety risks (in some cases for both the public and the workers) grows…

This happens in software too. Over the last 4 years our team has achieved a lot: huge numbers of valuable changes and improvements to our platform. But it's been much harder than it might otherwise have been because we've had to make those changes with the systems in use. Had we started from scratch, or been able to take downtime, there are a lot of projects we could have done much more quickly, but we had to keep th…

Isn't this completely standard practice now?

Re: South Kensington station's escalator replacement project

#65

Post by lbriner » Tue, Aug 17, 2021, 2:28 PM UTC

adwww wrote: post #40

noneeeed wrote: post #15

Earlier quoted context omitted.

The only way to have express and stopping trains on the same track is to have frequent passing places. Scheduling and signalling get fiendishly complex. On somewhere like the underground, where building those extra passing places is really hard it just isn't worth it. This is one of the big missunderstandings about the HS2 line. Politicians focus on the shorter journey times, but the big win is actually increased cap…

Could you have odd / even trains that miss stops?

This creates a very significant passenger challenge. How do the customers know which train to get on and what if they get on the even stop and need to get off an odd stop? They have to change train. If they can't pass each other then they don't save much time.

In NY, the expresses are easier to understand because the rules are very simple.

Re: South Kensington station's escalator replacement project

#66

Post by lbriner » Tue, Aug 17, 2021, 2:29 PM UTC

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 ?

It is mainly due to an enormous expense and wanting to keep everything running during upgrades.

If you are already costing the taxpayer X million per year and then you want another 400M for an upgrade, are you likely to get it?

Re: South Kensington station's escalator replacement project

#67

Post by lbriner » Tue, Aug 17, 2021, 2:39 PM UTC

helloguillecl wrote: post #23

lbriner wrote: post #3

This is a great example of why underground railways are so expensive to run. I don't believe the London Underground has ever been profitable. Not only is it expensive to install equipment, you then have to maintain it and replace it and in this example, not even "like for like" are going to fit in the same space. When I used to go round various equipment rooms, there was electrical equipment that was the best part of…

I don't get why so many people and politicians speak about profitability as if it was an optional system for a modern city to have. Yes, the income via transportation fees are usually similar to operating expenses, but like it's the case with roads, no one should expect for it to cover the full cost of building the infraestructure, much like roads. The tube is not a part of a closed system and delivers thousands of o…

I don't think it is as much about profitability but more like who should pay for it. In one world view, the people who use it should pay for it, whatever that costs, in the ticket price. This gives direct pressure to keep costs down.

Another view is that it mostly benefits people in London so it should come out of London's Council tax (which I think part of it does).

The other view is that it is a general benefit to society and can and should be bankrolled by government. Then the problem is that the pressure to keep costs down is perhaps political and it is hard to know how much subsidy is fair.

Re: South Kensington station's escalator replacement project

#68

Post by lbriner » Tue, Aug 17, 2021, 2:41 PM UTC

sschueller wrote: post #17

lbriner wrote: post #3

This is a great example of why underground railways are so expensive to run. I don't believe the London Underground has ever been profitable. Not only is it expensive to install equipment, you then have to maintain it and replace it and in this example, not even "like for like" are going to fit in the same space. When I used to go round various equipment rooms, there was electrical equipment that was the best part of…

You have to maintain and replace all infrastructure eventually. Maintenance should be part of the project calculation and how items are maintained should also be part of that. Additionally how things are maintained needs to be updated to go with new technologies and methods. I see this with for example the public transport in Zürich, Switzerland. Some of the light rail is very old but they are maintenance revisions d…

Great in theory but if you are managing a system now, you would rather spend money on things you need now, you aren't going to keep it in the bank for some future day when the escalator needs replacing.

I suspect that equipment is depreciated in TfL accounts but the people 50 years ago wouldn't know how much this replacement would have cost so who knows.

Re: South Kensington station's escalator replacement project

#69

Post by gpvos » Tue, Aug 17, 2021, 3:53 PM UTC

noneeeed wrote: post #15

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 only way to have express and stopping trains on the same track is to have frequent passing places. Scheduling and signalling get fiendishly complex. On somewhere like the underground, where building those extra passing places is really hard it just isn't worth it. This is one of the big missunderstandings about the HS2 line. Politicians focus on the shorter journey times, but the big win is actually increased cap…

Re HS2: I am familiar with the capacity-and-speed-difference argument, but I recently found out[0] that the WCML, MML and ECML are all already four-tracked, so you already have separation of fast and slow trains. Is further separation really still worth it?

[0] I don't live in the UK, so I didn't know that yet despite being a railway nerd.

Re: South Kensington station's escalator replacement project

#70

Post by willyt » Tue, Aug 17, 2021, 4:27 PM UTC

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. Better to build a whole separate line, in fact this has been done already, the Victoria line is pretty much the express version of the Piccadilly line and likewise Crossrail will be the express version of the Central line.