I'm glad it's not me who has to clean this one up... - Page 1
Forum section: electronics / general

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: January 23, 2014, 09:37:27 pm
content: Concrete vs. railway signalling equipment - concrete wins!http://usvsth3m.com/post/74285062011/you-wont-believe-why-the-victoria-line-is-currently

author: AlfBaz
author_rank: Super Contributor
timestamp: January 23, 2014, 09:40:56 pm
content: It takes a special breed of meat head to f**k up that bad

author: jancumps
author_rank: Unknown
timestamp: January 23, 2014, 09:41:53 pm
content: It will take a special breed of tools to clean that up too

author: dr.diesel
author_rank: Super Contributor
timestamp: January 23, 2014, 09:50:17 pm
content: How do you accidently do that, are they sure it wasn't done intentionally?

author: rexxar
author_rank: Frequent Contributor
timestamp: January 23, 2014, 09:52:01 pm
content: How the hell do you even recover from something like this?

author: dr.diesel
author_rank: Super Contributor
timestamp: January 23, 2014, 09:56:23 pm
content: Concrete is water soluble until it sets up, then you can't, jack hammer time. You'd have to just rebuild it, starting over.

author: jancumps
author_rank: Unknown
timestamp: January 23, 2014, 09:56:41 pm
content: Quote from: dr.diesel on January 23, 2014, 09:50:17 pmOnce concrete is flowing, it's difficult to control, and difficult to get at that particular location to protect it.Ever tried running in a stream of flowing concrete?

author: dr.diesel
author_rank: Super Contributor
timestamp: January 23, 2014, 10:00:52 pm
content: Ah, I can see now, the second pict in the link. Looks like a block was pushed out from the weight of the concrete, filling the electrical room. I missed that the first time around.

author: Mechatrommer
author_rank: Super Contributor
timestamp: January 23, 2014, 11:05:23 pm
content: Quote from: dr.diesel on January 23, 2014, 09:56:23 pmwe have "tile stain remover" including that effectively removes dried concrete droplets. we need to buy many bottles though for this one.

author: dfmischler
author_rank: Frequent Contributor
timestamp: January 23, 2014, 11:25:21 pm
content: Unless it is "high early strength" concrete it ispretty soft for several days(in terms of response to jackhammers, drills, etc).

author: GreyWoolfe
author_rank: Unknown
timestamp: January 23, 2014, 11:34:36 pm
content: Me thinks that there will be someone/people who will be actively seeking new gainful employment.

author: GeoffS
author_rank: Unknown
timestamp: January 23, 2014, 11:39:35 pm
content: Quote from: dfmischler on January 23, 2014, 11:25:21 pmI imagine by the time the finger pointing stops and the paperwork to approve 'new/remedial' work is done, it will be too late for jack hammers.It is a government run institution after all.

author: SeanB
author_rank: Super Contributor
timestamp: January 24, 2014, 04:48:06 am
content: From the looks of the stuff it has both fast cure accelerators and flow enhancers in it. That means it went to about 60% of final 28 day cure strength in about 12 hours and got into every crevice. This was done to probably have a fast turnaround on the reinforcing done to the wall there so they could carry on work without a 4 week delay for shuttering to hold it in place for curing. Probably at around the 10MPa mark now and going up by the hour. Good mix though, no shortcuts used there and nice blending.Only way to get it out now is to drill down to the original floor with core bits and clear a spot then use expanding mortar or a hydraulic cracker to spall sheets off into the cavity. Equipment is going to all have to be replaced totally along with the wiring and racks, as it will be destroyed by this.

author: manticore00
author_rank: Regular Contributor
timestamp: January 24, 2014, 04:56:40 am
content: One thing I don't miss from my time in London was what a mess the underground was... If it wasn't signals not working, it was flooding in a station after rain(cuz it never rains in London, right?) or trains were delayed because of "leaves on the track" or because the rail workers had decided to go on strike(usually I support organized labor but when I saw what their pay rates were and what they were striking for my sympathy disappeared) or one of any other BS excuses that they'd come up with... Contrasting that with the time I spent living in Tokyo where you could set your watch by the train schedule left me in total disgust... A foul up like this doesn't surprise me as much as it should...

author: GeoffS
author_rank: Unknown
timestamp: January 24, 2014, 05:14:04 am
content: Quote from: SeanB on January 24, 2014, 04:48:06 amI'm sure that's of little comfort to the person currently looking for a new job

author: casinada
author_rank: Frequent Contributor
timestamp: January 24, 2014, 05:46:40 am
content: Not that tragic but I see similar things very often when we run network and telephony cables, if you are not careful other crews will cut them without thinking twice and the dry wallers and painters will put mud and paint all over them without a bit of careBut the concrete one is a little bit more serious.

author: TerraHertz
author_rank: Super Contributor
timestamp: January 24, 2014, 07:37:52 am
content: It's most amusing how it looks like someone made a last ditch stand with a spade, trying to shovel the concrete back. Vis the spade-splashes higher up the racks, and the concrete surfaces that have flat sweep planes, like someone was troweling it.Maybe the contractor, going 'oh f*ck oh f*ck oh f*ck!' Pity there's no video.Actually, if they'd had a few guys there with spades at the right time, just as the concrete was beginning to set, they could have dug it away from around the racks. Then quickly water pressure spray hoses and a big suction pipe to wash the crete off the equipment before it completely set, and very rapidly after that take everything apart, re-wash then blow & bake dry. Might have been able to salvage the gear and get it working again pretty quickly.But I doubt it would be considered safety rated after that, therefore not usable, so why bother trying?

author: nctnico
author_rank: Super Contributor
timestamp: January 24, 2014, 08:32:49 am
content: Quote from: manticore00 on January 24, 2014, 04:56:40 amAnd yet I prefer the London underground over the public transport system we have in the NL. In the city I live in it is faster to walk than to wait for the bus despite a seperate system of bus lanes throughout the city. Using a bicycle is even faster...On topic:It is a mess indeed. It would'nt surprise me if it is cheaper to tear everything from the room and rebuild it on top of the layer of concrete. It says 3 rows of relays have been submerged which leads me to suspect the layer is at least 50 to 60cm thick (about 2 feet). Hammering it out without damaging the floor beneath will be a nightmare but also removing the debris the will be a though job.@TerraHertz: These relays are extremely expensive. So expensive that the Amsterdam underground system is 'computer controlled' (probably a PLC) instead of using relays.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: January 24, 2014, 09:19:03 am
content: Heard on the news that they were back up & running after all-night working, only losing 10 hours of service. OK it's probably a temporary fix, but that's damn impressive for such an un-forseeable failure mode.

author: VK5RC
author_rank: Unknown
timestamp: January 24, 2014, 09:32:52 am
content: It shouldn't be that bad, I thought you could stop concrete setting by adding ? sugar, I don't think you need much, then you have a 'mud' problem,

author: IanB
author_rank: Super Contributor
timestamp: January 24, 2014, 09:35:07 am
content: Quote from: nctnico on January 24, 2014, 08:32:49 amInteresting. I'm not sure what the relays are used for, since the Victoria line has a new automatic train operation system with modern computer controlled signalling. I suspect the relays are not directly involved in normal train signalling, but have an indirect purpose such as for block markers, controlling access to reversing bays and/or access to the depot for instance.

author: AlfBaz
author_rank: Super Contributor
timestamp: January 24, 2014, 11:32:14 am
content: Quote from: IanB on January 24, 2014, 09:35:07 amIt may well be some legacy gear, remember to, that early plc's needed external relays for just about everything

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: January 24, 2014, 11:52:17 am
content: To all the guys saying how could this happen, much stupid, wow failtrain, ect. This can happen easy, you would know if you have ever laid concrete, it's called a form blow-out. Concrete is damm heavy and once an inadequate form gives way gravity does the rest.

author: atw60444
author_rank: Contributor
timestamp: January 24, 2014, 12:05:29 pm
content: I've been following some posts by an Ex LUL signalling engineer on a Strowger mailing group.A lot of the signalling infrastructure was upgraded in the 1990's and these are modern relays.The Victoria line has Automatic Train Operation, ATO. This was also upgraded for new rolling stock introduced in the past couple of years.The "driver" is really just their for safety. Opens and closes the doors. And can move the train at low speed if there is a system failure, just to detrain the passengers at the next station. He describes these as Q relays used in "Line and Track" which I take to mean indicating train positions & monitoring/controlling circuit breakers for point operation I would also imagine there are still signal lamps of some description.

author: JoeO
author_rank: Frequent Contributor
timestamp: January 24, 2014, 02:31:05 pm
content: The latest story about the cleanup, with a picture. They did use sugar!! It looks surprisingly good.http://www.telegraph.co.uk/science/science-news/10594718/Why-sugar-helped-remove-Victoria-Line-concrete-flood.html

author: Bored@Work
author_rank: Super Contributor
timestamp: January 24, 2014, 05:44:57 pm
content: Quote from: JoeO on January 24, 2014, 02:31:05 pmAnd looks like they replaced the relays.

author: kfitch42
author_rank: Frequent Contributor
timestamp: January 24, 2014, 06:40:59 pm
content: The cleanup was actually pretty impressive/quick. I am about 110% sure that if this happened in the DC metro, there would problems for 6+ months while the slowly squeezed new equipment in a slightly shorter room.

author: BillyD
author_rank: Regular Contributor
timestamp: January 24, 2014, 08:02:20 pm
content: Quote from: TerraHertz on January 24, 2014, 07:37:52 amYou're so right, I laughed out loud when I read that. It reminds me of that immeasurably tiny unit of time, the 'Ohnosecond', which is the duration between fucking something up and realising what you've done or are about to do.Have to say I quite sympathise with them, I've had a few near disasters with concrete myself and it's very hard to recover if it ever starts getting out of control like that. Hats off to them for getting it fixed up so quickly.

author: GreyWoolfe
author_rank: Unknown
timestamp: January 24, 2014, 09:40:12 pm
content: How good of an oscilloscope would you need to measure the rise and fall times of the ohnosecond?

author: dexters_lab
author_rank: Unknown
timestamp: January 24, 2014, 09:57:07 pm
content: it's been all over the news today, quite funny really!brings a whole new meaning to potted electronics!

author: dfmischler
author_rank: Frequent Contributor
timestamp: January 24, 2014, 10:06:38 pm
content: Quote from: GreyWoolfe on January 24, 2014, 09:40:12 pmI'm pretty sure that it can't be measured in the real world. If you are anticipating a major screw-up then it is far less likely to happen. Nobody who knows that their ohnosecond is about to be measured is going to give you the satisfaction. I suspect Heisenberg comes into play, too

author: tealsuki
author_rank: Contributor
timestamp: January 24, 2014, 11:22:36 pm
content: I'll always know to keep a bag of sugar on hand in case of a cement accident now! I hope the people responsible didn't get too much shit for it

author: nctnico
author_rank: Super Contributor
timestamp: January 25, 2014, 12:18:40 am
content: Quote from: JoeO on January 24, 2014, 02:31:05 pmI never heard about using sugar. The people pouring the concrete must have had similar f* ups before so they always have sugar on hand. Still it is a very good job cleaning such a mess up this quick

author: VK5RC
author_rank: Unknown
timestamp: January 25, 2014, 04:48:08 am
content: I heard about the sugar in concrete trick from my late father a Uni lecturer civil engineering, apparently it was used as a 'industrial/financial threat' to some large concrete pours and I think it was one of the reasons the twin towers in NY had a steel structure, once a big concrete pour starts, stopping it is almost impossible from a structural and practical viewpoint.