"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.

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.

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

Never had any other car that way round.

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

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