Blue railway signals?

"JNugent" wrote in message
...
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?

https://www.google.com/search=traffi...+snow&tbm=inch

Interesting that it mostly appears to be driven show forming a disc
over the entire lens rather than a pile that eventually gets high
enough to obscure the top one, sitting on the visor of a lower one.

On Fri, 14 Dec 2018 22:59:29 -0000, Steve Walker wrote:

On 14/12/2018 18:22, Fred Johnson wrote:
People with colour blindness shouldn't drive trains (or cars for that
matter).

And it's not very many, in fact I know of only one person who's
colourblind.

It matter for railways due to needing to determine the colour from a
long distance, due to the long stopping distance of a train. It is fine
for a colourblind person to drive a car, as the stopping distance is
short enough for the driver to get close enough to determint the
position of the light on traffic light.

Not so. I can see a red light (or brake light) out of the corner of my eye and act immediately.
A colour blind person cannot do that and will react later than me.

Up to eight percent of men of North European decent are red-green colour
blind.

A small number. Let them walk.

On Fri, 14 Dec 2018 22:59:29 -0000, Steve Walker wrote:

On 14/12/2018 18:22, Fred Johnson wrote:
People with colour blindness shouldn't drive trains (or cars for that
matter).

And it's not very many, in fact I know of only one person who's
colourblind.

It matter for railways due to needing to determine the colour from a
long distance, due to the long stopping distance of a train. It is fine
for a colourblind person to drive a car, as the stopping distance is
short enough for the driver to get close enough to determint the
position of the light on traffic light.

Up to eight percent of men of North European decent are red-green colour
blind.

Since when were Northern European men decent? :-)

On Sat, 15 Dec 2018 00:40:37 -0000, Rod Speed wrote:



"JNugent" wrote in message
...
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?

https://www.google.com/search=traffi...+snow&tbm=inch

How did you manage to misspell isch as inch as part of a URL? Did your spellchecker treat it as a word? The worrying thing is my brain immediately spotted inch as incorrect for a google search parameter.

You also omitted ?q after the word search. You can't insert parameters without a ? to indicate them.

Interesting that it mostly appears to be driven show forming a disc
over the entire lens rather than a pile that eventually gets high
enough to obscure the top one, sitting on the visor of a lower one.

Because vertically falling snow with no wind can't get to the lower visors, due to the upper visors getting in the way. It has to be snow on a windy day.

Also interesting those are all in the USA, although I guess they get more snow than the UK. Or maybe our lights are more slippery?

On Fri, 14 Dec 2018 00:55:55 -0000, Rod Speed wrote:



"Fred Johnson" wrote in message
news
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:



"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.

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

The yanks feel otherwise.

The yanks don't think at all.

(except two or more way switches of course).

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.

But you do see it with power switches.

Not here. They're similar to light switches, although more rugged as they switch a higher current.

Anyway with automatic ones, there are no switches.

There are in mine.

A couple of mine have manual overrides, my bedroom for example is normally on a 15 second timer, so it goes off just after I get into bed, but sometimes I press the switch to leave it on if I'm doing something else in there. And don't go inserting rude things!

But most of them are auto only. I can always make them come on when it's light by covering the sensor momentarily.

And with whether hot and cold taps have the
hot one on the right of the pair or the left.

I can never remember which way round mine are, until I go to use one.
Because when I use one in another house that's the other way round, I
always get it wrong.

Never had any other car that way round.

Yeah, the frogs are much worse for that than most.

They even speak backwards, putting the noun before the adjective.

And some buggers even write backwards.

Muslims.

Like I said, whenever there is more than one way to do it,
you can be sure some will do it one way and some the other.

Yes, there are always morons.

Every time I try to turn on the wipers, I'm pushing it the wrong way.
One day I'll snap it off.

"Fred Johnson" wrote in message
news
On Fri, 14 Dec 2018 08:45:09 -0000, The Natural Philosopher
wrote:

On 13/12/2018 16:57, Steve Walker wrote:
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?

Never heard of it.

4 (& 5)-aspect signals have always had red, green and two ambers as far
as I know.

I know that the semaphore signals had lenses that were red and blue, but
they definitely showed as red and green when lit from behind by
yellowish oil lamps at night.

SteveW

No, Blue was never part of railway standard signals. I am very hazy but
ISTR two amber - sequnec being green-two amer - one amber - red as the
obstruction was approached..

ISTR blue was something one saw on te railways but it wasn't part of the
standard signals

Yes it was probably a light for something else I saw. Google refers to it
being used for tunnels etc. Mainly for markers to show where an edge is
(not sure why a train needs to know that, after all they can't be
steered....)

Its in case the train breaks and you need to walk out of the tunnel, stupid.

On 14/12/2018 22:59, Steve Walker wrote:
On 14/12/2018 18:22, Fred Johnson wrote:
People with colour blindness shouldn't drive trains (or cars for that
matter).

And it's not very many, in fact I know of only one person who's
colourblind.

It matter for railways due to needing to determine the colour from a
long distance, due to the long stopping distance of a train. It is fine
for a colourblind person to drive a car, as the stopping distance is
short enough for the driver to get close enough to determint the
position of the light on traffic light.

Up to eight percent of men of North European decent are red-green colour
blind.

SteveW

I have lost 90% of color vision on the center of my left eye


--
Outside of a dog, a book is a man's best friend. Inside of a dog it's
too dark to read.

Groucho Marx

On 15/12/2018 01:00, Kristy Ogilvie wrote:
On Fri, 14 Dec 2018 22:59:29 -0000, Steve Walker
wrote:

On 14/12/2018 18:22, Fred Johnson wrote:
People with colour blindness shouldn't drive trains (or cars for that
matter).

And it's not very many, in fact I know of only one person who's
colourblind.

It matter for railways due to needing to determine the colour from a
long distance, due to the long stopping distance of a train. It is fine
for a colourblind person to drive a car, as the stopping distance is
short enough for the driver to get close enough to determint the
position of the light on traffic light.

Up to eight percent of men of North European decent are red-green colour
blind.

Since when were Northern European men decent?Â* :-)

Since they put on clothes to keep the ice and snow out?


--
Outside of a dog, a book is a man's best friend. Inside of a dog it's
too dark to read.

Groucho Marx

On 15/12/2018 01:10, Kristy Ogilvie wrote:
And don't go inserting rude things!

Don't you like it, then?


--
If I had all the money I've spent on drink...
...I'd spend it on drink.

Sir Henry (at Rawlinson's End)

On Sat, 15 Dec 2018 16:52:25 +1100, cantankerous trolling geezer Rot Speed,
the auto-contradicting senile sociopath, blabbered, again:


Yes it was probably a light for something else I saw. Google refers to it
being used for tunnels etc. Mainly for markers to show where an edge is
(not sure why a train needs to know that, after all they can't be
steered....)

Its in case the train breaks and you need to walk out of the tunnel, stupid.

Bunch of senile idiots here are firmly in the grip of the attention-starved
Scottish sow! BG

--
Norman Wells addressing senile Rot:
"Ah, the voice of scum speaks."
MID: