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Post by fabieng on Jan 16, 2021 7:25:36 GMT
Dear all, I have a question and you may be able to answer. There are many different clocks in the stations. When these clocks are too old, broken, and need to be replaced, are they nowadays replaced by the same one single model of clock? If yes, which brand is it? Is it possible for an individual to buy one? In the LT museum shop they only sell small clocks, and I tried to contact LT and never recieved any answer. I imagine it maybe black or silver, with red digit, like this one maybe?: (chromus newgate large wall clock) www.onlinereality.co.uk/prod/28721/chromus-newgate-large-wall-clockBut Newgate told me they were not the official LT clock supplier, and on their own website they don't even sell this. I have seen pictures of London tube stations clocks having a roundel logo, but these clocks seem relatively old to me. It is well known that the brand Mondaine is the official Swiss railway clock, and it's possible to buy them. The London transport tube and its is roundel is so world famous that I am surprised that I can't see an official clock of the London Tube to buy anywhere. Thanks for your answers. Fabien |
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Tom
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Post by Tom on Jan 16, 2021 18:07:57 GMT
Westerstrand supplied a few clocks to LT over the years - try here. |
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Chris L
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Post by Chris L on Jan 16, 2021 18:18:48 GMT
Most if not all the clocks on the Underground are controlled from a central clock. I'm not sure they would be much use to you.
Many years ago every clock had to reset twice a year by teams visiting the stations. A major exercise.
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Post by stapler on Jan 17, 2021 22:01:58 GMT
In the trade, they are called "slave dials"....
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Post by brigham on Jan 18, 2021 8:46:31 GMT
Is there anything to stop a third party from marketing a domestic clock in the style of an 'official' LT one?
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Chris L
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Post by Chris L on Jan 18, 2021 9:09:50 GMT
Is there anything to stop a third party from marketing a domestic clock in the style of an 'official' LT one? The roundel is a protected trade mark. |
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Tom
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Post by Tom on Jan 18, 2021 19:14:34 GMT
But many 'official' clocks don't feature roundels - only a minority.
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Chris M
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Post by Chris M on Jan 18, 2021 23:22:38 GMT
The design of those clocks may be trademarked and/or copyrighted by their designers or TfL
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Post by fabieng on Jan 22, 2021 10:28:29 GMT
Thank you for your answers.
I'll have a look at Westerstrand.
I understand all clocks must be centrally controlled, I imagine indeed the time it would take if all the LU clocks were working with a simple common battery and needed to be time-checked twice a year!
But, as I explained with my example, the Swiss rail Mondaine clocks, that work with the same central system, have produced a commercial model for people to buy.
I was not specifically expecting the old clock with the roundel replacing the numbers, I don't know what is the common replacement clock nowadays in the LU as I don't live in England.
Maybe when a clock nowadays is removed it is not replaced by another, maybe it's just by digital numbers in the lightbox?
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Post by zbang on Jan 22, 2021 17:05:54 GMT
Most if not all the clocks on the Underground are controlled from a central clock. I'm not sure they would be much use to you. Virtually all mechanical "slave" clocks operate perfectly well on their own, the Master signal usually serves to reset the clock to a specific time* (often 12:00:00, 00:00:00, or xx:00:00), for some gory details see Electrical Timekeeping (F. Hope-Jones**, www.abebooks.com/book-search/title/electrical-timekeeping/), which is ahem, rather dense, technically.
*The Western Union clocks worked that way
**Brother of Robert Hope-Jones, the organist and organ designer
Digital clocks come in two flavors- simple display repeaters which have no internal timing source (often used in broadcast stations and control rooms) and full-on clocks which use the external source to either set the display time or to adjust their rate, those will usually operate without a master signal.
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class411
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Post by class411 on Jan 22, 2021 19:05:55 GMT
Most if not all the clocks on the Underground are controlled from a central clock. I'm not sure they would be much use to you. Virtually all mechanical "slave" clocks operate perfectly well on their own, the Master signal usually serves to reset the clock to a specific time* (often 12:00:00, 00:00:00, or xx:00:00), for some gory details see Electrical Timekeeping (F. Hope-Jones**, www.abebooks.com/book-search/title/electrical-timekeeping/), which is ahem, rather dense, technically. *The Western Union clocks worked that way
**Brother of Robert Hope-Jones, the organist and organ designer Digital clocks come in two flavors- simple display repeaters which have no internal timing source (often used in broadcast stations and control rooms) and full-on clocks which use the external source to either set the display time or to adjust their rate, those will usually operate without a master signal. Thanks for that. I'd been wondering how they avoided losing pulses over the hundreds of clocks on the system - having assumed that they were being sent a pulse per second. A bit daft of me, really, as I should have realised that they'd employ the same system as atomic synched clocks. (Note for pedants: They do actually transmit a pulse per second as well as coded time stamps, but every clock and watch that I've looked at the specs of uses the 'once a day' method). |
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Post by zbang on Jan 23, 2021 7:14:47 GMT
I should have mentioned that there is an over-the-air source of precision time, known as the "NPL", "MSF" or "Rugby" clock, but being a radio signal it doesn't work too well underground. If any kind of Internet Protocol connectivity is available, precise time can be distributed via Network Time Protocol (NTP) but I'd only expect that for display boards that would have a connection for the other information. My assumption is that telegraphic connections were used if there wasn't someone riding around with a precision watch to check them.
(Now I'm going to go down the rat-hole of time distribution....)
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Post by rincew1nd on Jan 23, 2021 14:57:57 GMT
I should have mentioned that there is an over-the-air source of precision time, known as the "NPL", "MSF" or "Rugby" clock.... (Now I'm going to go down the rat-hole of time distribution....) Isn't the MSF signal now broadcast from Cumbria? Edit to add: yes www.npl.co.uk/msf-signal |
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class411
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Post by class411 on Jan 23, 2021 15:05:57 GMT
It moved in 2007, and, annoyingly, in some areas (including mine), the signal is weaker from the Anthorn station than it was from Rugby.
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Post by brigham on Jan 23, 2021 15:35:54 GMT
Not ONE of the 'slave' clocks I've ever come across has had ANY timekeeping capability whatsoever.
They have ALL moved one position (usually ½ minute) per pulse.
Some electric clocks have a spring-driven reserve, in case of interruptions of the electric supply, though.
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class411
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Post by class411 on Jan 23, 2021 17:56:57 GMT
Not ONE of the 'slave' clocks I've ever come across has had ANY timekeeping capability whatsoever. They have ALL moved one position (usually ½ minute) per pulse. Some electric clocks have a spring-driven reserve, in case of interruptions of the electric supply, though. But were they slave clocks that were operating a a considerable distance (i.e. miles) from the master? Within a building it's perfectly reasonable to expect every pulse to get were it's supposed to. Over a railway network, not so much. |
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Post by zbang on Jan 23, 2021 18:13:53 GMT
Not ONE of the 'slave' clocks I've ever come across has had ANY timekeeping capability whatsoever. They have ALL moved one position (usually ½ minute) per pulse. Some electric clocks have a spring-driven reserve, in case of interruptions of the electric supply, though. I guess that becomes a matter of terminology- many people would say a unit without a timing element isn't really a clock, it's a display or a repeater. PPM-driven displays certainly work in a single facility when driven from a local timing source, but that source would either have to get some sort of master resync from elsewhere or run wild and be manually reset from a precision watch.
There are references to clocks made by the "Self Winding Clock Company", which invented the "reset to the hour" mechanism, at Acton Town, Chalk Farm, Colindale, Earl's Court, and a few others. Electrical Timekeeping mentions "A somewhat similar arrangement [ref to the previous page] is adopted by the Self-winding Clock Company of New York, and an installation of the clocks is still in use on the underground railways of London, controlled by a master clock at Lots Road Generating Station."
BTW, one of the references I saw mentioned that because of the early adoption of block signaling in the UK and especially on the London lines [and I extend that all of the various train control systems devised], the railways there weren't nearly as time-centric for operations as in other countries. Make of that what you will.
Edit- correct punctuation. |
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Post by Chris M on Jan 23, 2021 19:47:05 GMT
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Post by Tom on Jan 23, 2021 22:28:27 GMT
There is a David Burton who works at TfL ( LinkedIn), who may be the author and if so may be able to help you if asked. It's the same individual. He gave a talk to the London Underground Railway Society about the evolution of station lighting a couple of years ago. |
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Post by brigham on Jan 25, 2021 9:28:37 GMT
Not ONE of the 'slave' clocks I've ever come across has had ANY timekeeping capability whatsoever. They have ALL moved one position (usually ½ minute) per pulse. Some electric clocks have a spring-driven reserve, in case of interruptions of the electric supply, though. But were they slave clocks that were operating a a considerable distance (i.e. miles) from the master? Within a building it's perfectly reasonable to expect every pulse to get were it's supposed to. Over a railway network, not so much. I'll know more when my copy of Electrical Timekeeping (F. Hope-Jones) arrives. Meanwhile, I've just remembered the Waiting Train movement. The clock runs over 30 seconds on the dial in about 29 seconds, then waits for the pulse to set it away for the next spasm. The 'waiting train', of course, is a train of gears, and nothing to do with railways. |
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Post by fabieng on Feb 1, 2021 21:06:21 GMT
Thank you for your answers, interesting to read. But so, it seems you don't know everything about the tube ?!  I'll keep searching then. |
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Post by fabieng on Feb 8, 2021 19:01:28 GMT
I finally recieved an answer from LT:
“Regrettably there isn’t an ‘official’ supplier of clocks to Transport for London, like for example Gents of Leicester from bygone days. This is a thing of the past, an era that’s gone now. In terms of our surviving old clocks in some of our mainline stations, the mechanisms for these are almost infinitely replaceable so are unlikely to need full replacement. If they do, then we would opt for digital signs that provide more information than just the time.” Alex C.
Thank you again.
Keep up the good job with the forum and enjoy London/England you lucky people.
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