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Post by ijmad on May 10, 2023 9:34:23 GMT
Purely for my own interest: I know that train drivers are tested for colour blindness, but is this just red/green or also red/blue? Just thinking about these new signal colours.
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Post by Dstock7080 on May 10, 2023 13:05:46 GMT
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Post by t697 on May 10, 2023 15:44:41 GMT
Not so handy for the west end of the District then...
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Post by ijmad on May 10, 2023 18:04:32 GMT
Do you think Met and/or Chiltern drivers will need to be tested for red/blue colour blindness as a result of these blue aspects being introduced alongside the other colours? I suppose if they failed such a test, LU could offer them an equivalent position on one of the lines that no-longer has lineside signals. |
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Colin
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Post by Colin on May 10, 2023 18:26:22 GMT
Do you think Met and/or Chiltern drivers will need to be tested for red/blue colour blindness as a result of these blue aspects being introduced alongside the other colours? Having done some basic research, I came across this piece of text which explains the answer.... "Being ‘red/green colour blind’ means people with it can easily confuse any colours which have some red or green as part of the whole colour. So someone with red/green colour blindness is likely to confuse blue and purple because they can’t ‘see’ the red element of the colour purple." On that basis I would suggest the red/green colour blindness test currently in use is sufficient to cover blue aspects. |
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Post by d7666 on May 11, 2023 0:11:12 GMT
red/blue colour blindness ? ‘red/green colour blind’ means people with it can easily confuse any colours which have some red or green as part of the whole colour. So someone with red/green colour blindness is likely to confuse blue and purple because they can’t ‘see’ the red element of the colour purple." Slightly digressing, on the continent, there are a lot of blue signals in assorted uses in different lands. At least one continental operator I can think of uses purple - the Swiss BLS does for a specific (possibly unique) application that is way off topic for here. GB generally is possibly even a minority in having only red / yellow / green white lamp colours, quite a lot have one more, blue or purple or some shade in between blue and purple. Colour blindness w.r.t. more lamps than RYG can't be an issue: despite what some might think, continental trains are driven by similar humans with similar potential defects to those on this island. |
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rincew1nd
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Post by rincew1nd on May 11, 2023 9:19:17 GMT
GB generally is possibly even a minority in having only red / yellow / green white lamp colours, quite a lot have one more, blue or purple or some shade in between blue and purple. Blue has been used in Britain on the mainline network for a little while now, RETB areas use a flashing blue to indicate that the TPWS loops are de-energised. |
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Post by Chris L on May 12, 2023 5:40:42 GMT
A former girlfriend was red/green colour blind.
I asked her how she saw traffic signals. Her answer was the top light is stop and the bottom light go.
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Post by ijmad on May 12, 2023 9:28:53 GMT
A former girlfriend was red/green colour blind. I asked her how she saw traffic signals. Her answer was the top light is stop and the bottom light go. Tell her to avoid Syracuse, NY
Though already, I guess that technique wouldn't work on the railways, due to the increasing use of searchlight-type signals where different colours are displayed in the same light, like this one:  |
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Post by d7666 on May 12, 2023 14:02:13 GMT
RETB areas use a flashing blue to indicate that the TPWS loops are de-energised. Flashing blue ? Flashing red surely for points failure. www.railsigns.uk/sect11page3.htmlfig 11.53 Or are you describing something else; I have never heard of TPWS failure signal giving a trackside indication to a train; I can't quickly locate any flashing blue on that web site which is up to date and precise. |
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Post by rincew1nd on May 12, 2023 15:27:02 GMT
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Post by trainwizard on May 12, 2023 19:55:19 GMT
I asked her how she saw traffic signals. Her answer was the top light is stop and the bottom light go. Tell her to avoid Syracuse, NYOr perhaps the US in general. I've seen many horizontal traffic lights across the pond, and I'm not sure if there's a common way to order the colours (and if there is, it's quite unknown). I've also seen some traffic lights that use shapes to help distinguish between colours, such as this one in Canada - a possible solution to implement on railways. I find it ironic and disappointing that the colours used to represent opposites in society also happen to be the most common colour blindness (red-green). |
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Post by d7666 on May 12, 2023 20:39:17 GMT
Ta. I'd not found that detail before. New one on me. |
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Post by d7666 on May 12, 2023 21:36:00 GMT
some traffic lights that use shapes to help distinguish between colours, ............ - a possible solution to implement on railways. Not sure that shaped lights would be of much use on railways. Railway signals need to be seen at much much further sighting distance than ever a road traffic light is. No way could squares or circles or triangles be distinguished at train sighting distance. Anyone who had a sight disability such that they could not distinguish colours but could the shapes is unlikely to ever be let into a train cab to drive one. |
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Post by brigham on May 13, 2023 7:40:27 GMT
As for shapes of signs, I'm reliably informed by a road-mender that, years ago, a diktat came from on-high that the STOP side of a stop-go board had to be octagonal, rather than round.
Presumably for the benefit of colour-blind drivers who cannot distinguish the word STOP from GO.
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Post by bomo on May 13, 2023 12:17:39 GMT
A former girlfriend was red/green colour blind. I asked her how she saw traffic signals. Her answer was the top light is stop and the bottom light go. I suspect she was being flippant.
I'm red/green colour blind too and like most people with the condition it's not absolute and, as alluded to above, affects a variety of colours with a red component. It also varies wildly according to so many things like distance, ambient light, colour shades, background etc and it is totally impossible to explain to someone what it is like as there is no alternative point of reference to describe colour. I'm in my 60s now and have a life time of being asked "what colour does grass look like" type questions so flippant responses end up coming naturally and I've used the red is top, green is bottom one for traffic lights so many times.
For the record I can see the colours of traffic lights perfectly well irrespective of their orientation. Actually the transport related thing I have most trouble with is the 60+ Oyster card validity map. This is an absolute nightmare for someone with the condition and my repeated requests to TfL that it be changed to something easier for a typical red/green colour blind person to decipher have been totally ignored.
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Post by d7666 on May 13, 2023 19:28:14 GMT
STOP side of a stop-go board had to be octagonal, rather than round. Presumably for the benefit of colour-blind drivers who cannot distinguish the word STOP from GO. We are into serious digression here, but as far back as I can remember octagonal stop signs are so because as a general thing such a fixed stop sign could become covered in say snow, or with sun behind seen only as a silhouette, and, for consistency a temporary stop/go follows suite. So the shape is still there in all cases. Likewise a 'give way' / 'yield' sign is an inverted triangle apex down as opposed to base down of other triangular signs, its shape is still there, snow covered or in silhouette. |
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