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#41
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Blue railway signals?
On 14/12/2018 00:47, Steve Walker wrote:
On 13/12/2018 23:12, Rod Speed wrote: "Fred Johnson" wrote in message news On Thu, 13 Dec 2018 21:03:57 -0000, Mike Humphrey wrote: Fred Johnson wrote: Can anybody else remember blue traffic lights on railways?* Can't find any evidence on google.* I'm sure whereas cars have red/amber/green, railways always had a 4th blue light.* What does it mean and why has it disappeared from Google? Railway signals in modern times have always had red, yellow (not amber) I've never been fussy enough to even notice the difference between yellow, amber, orange.* I could tell the difference if they were side by side, but I just think of a road traffic light as either yellow or orange.* I couldn't even tell you what amber colour is compared to yellow and orange. I don't do things like "mauve", etc.* Just purple, light purple, etc. and green. A four-aspect signal has two yellows - the sequence approaching a stop signal goes G, YY, Y, R. There can be a number of other indications as well as the main signal but these are almost invariably white. I assume this is to allow trains the longer stopping distance they require than road vehicles. There's a number of uses for blue and purple, but not appearing with the R/Y/G "traffic light" signals, at least in the UK. I might be thinking of non "traffic light" signals, or I might be thinking of a light which was off and was just seeing the blue lens which had a yellow light behind to make green. If you want to look at the full range of signs and signals, http://www.railsigns.uk/ has a very comprehensive guide. That's a lot for a driver to remember!* At least with road signs the symbol is meaningful. I wonder why the red is at the bottom on rail lights and the top on traffic lights? Basically because when there are two ways of doing something, you can be sure someone will do it both ways. I am sure that I remember reading that it was based upon upper-quadrant semaphore signalling, where a raised signal was "off" (clear) and horizontal one was "on" (danger). Although both upper and lower quadrant signals were used in the UK, they were almost all UQ (except on GWR lines) from the 1920s - with the advantage that broken cables or heavy snow caused them to drop to danger rather than the clear of LQ ones. They simply copied UQ practice, so the top was clear and the bottom danger. Yebbut with semaphore signals the light is always in the same position. -- Max Demian |
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#42
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Blue railway signals?
On 14/12/2018 09:27, Rod Speed wrote:
Nightjar wrote Fred Johnson wrote I wonder why the red is at the bottom on rail lights and the top on traffic lights? On railways it is at the bottom so that there is no light shade below it, on which snow could build up and obscure the light. So why didn't that continue with street lights ? Perhaps the American who invented them hadn't thought about that problem. Overground railway light signals were not standardised until rather later - in 1924. -- -- Colin Bignell |
#43
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Blue railway signals?
On 13/12/2018 16:42, Fred Johnson wrote:
Can anybody else remember blue traffic lights on railways?* Can't find any evidence on google.* I'm sure whereas cars have red/amber/green, railways always had a 4th blue light.* What does it mean and why has it disappeared from Google? I have found a reference to an historic use of purple lights to indicate there is a track circuit, which is a system to detect the presence of a train. -- -- Colin Bignell |
#44
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Blue railway signals?
On 14/12/2018 11:33, Nightjar wrote:
On 14/12/2018 09:27, Rod Speed wrote: Nightjar wrote Fred Johnson wrote I wonder why the red is at the bottom on rail lights and the top on traffic lights? On railways it is at the bottom so that there is no light shade below it, on which snow could build up and obscure the light. So why didn't that continue with street lights ? Perhaps the American who invented them hadn't thought about that problem. Overground railway light signals were not standardised until rather later - in 1924. I have never seen a set of road traffic lights obscured by built-up snow, not even during the worst of UK blizzards. Has anyone else? |
#46
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Troll-feeding Senile IDIOT Alert!
On Fri, 14 Dec 2018 11:22:05 +0000, Max Demian, an especially stupid,
notorious, troll-feeding, senile idiot, blathered And with whether hot and cold taps have the hot one on the right of the pair or the left. Usually hot is on the left. LOL I've warned you senile idiots: after a few posts you all start sounding as idiotic and ridiculous as the ****ed up Scottish ****** that you keep feeding! |
#47
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Troll-feeding Senile IDIOT Alert!
On Fri, 14 Dec 2018 09:14:06 +0000, Nightjar, another brain dead,
troll-feeding, senile idiot, driveled: On railways it is at the bottom so that there is no light shade below it, on which snow could build up and obscure the light. Source ...other than your senile brain, troll-feeding senile idiot? |
#48
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Troll-feeding Senile IDIOT Alert!
On Fri, 14 Dec 2018 11:44:49 +0000, Nightjar, another brain dead,
troll-feeding, senile idiot, driveled again: I have found a reference to an historic use of purple lights to indicate there is a track circuit, which is a system to detect the presence of a train. Are you two idiots planning on driving trains or what? Or are you simple babbling away idiotically again because you got no one else in real life to babble with? VBG |
#49
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Troll-feeding Senile IDIOT Alert!
On Fri, 14 Dec 2018 15:12:11 -0000, Terry Casey, another mentally
challenged, troll-feeding, senile idiot, blathered: No actual blue signals, though. Just a load of useless inane troll fodder though, eh, troll-feeding senile idiot? |
#50
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Blue railway signals?
On Fri, 14 Dec 2018 11:22:05 -0000, Max Demian wrote:
On 14/12/2018 00:20, Fred Johnson wrote: On Thu, 13 Dec 2018 23:43:41 -0000, Rod Speed wrote: "Fred Johnson" wrote in message news On Thu, 13 Dec 2018 23:12:50 -0000, Rod Speed wrote: Basically because when there are two ways of doing something, you can be sure someone will do it both ways. Like my bloody French car which has the wiper switch going down to increase speed. And with light and power switches in houses etc. Down should always be on (except two or more way switches of course). USA It's down for on in the UK in almost every switch I've seen. And then some bugger shows up who decides to do them sideways so there is no confusion at all, and we end up with 4 different ways of doing it instead of just 2. Never seen a sideways lightswitch in a house. Japan Because they're too short to reach high enough to reach one that goes up? And with whether hot and cold taps have the hot one on the right of the pair or the left. Usually hot is on the left. Seems to be that way on all my sinks, but I'd say in other people's houses I see it the other way round in about 20% of cases. When I were a lad, the bathroom sink was definitely the other way round, can't remember the kitchen sink. |
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