There are some sound sites on the web about signalling and although I can't
help with the dates (I believe ground signals would have been around as long
as standard semaphores) you are right in that they were both concurrent.
What makes our question a little awkward is that semaphore signals had
colour lights fitted to them (some gas ones before elctricity) both for poor
lighting (night and fog) as well as difficult locations (in tunnels etc) and
this would be the same for the ground signals. One of the common ground
signals is an illuminated disc with a bar (semaphore style) which is either
horizontal or diagonal for stop and proceed.
Is your question actually about colour light ground signals rather than
illuminated semaphore types?
thanks for responding
you point out something that I had forgotten. Being 30 years away from the
hobby, I forgot that semaphores had illuminated "tails". not sure if all or
always, but I do recall now, thanks.
the purpose of my question is to establish the relative authenticity of
building a layout which dates from say, 1870 - 1925 and having a mix of
signalling throughout. I was hoping to find out if semaphores had started to
be replaced by this time, by illuminated-only signalling and if ground
signals were used through this time...... being an Aussie, I don't really
know if ground-based signals were used in the UK.
Interesting comment about that diagonal bar - it is probably what started
all the international symbols for "NO something or other", if you get my
meaning. As someone who works as a graphic designer, I find this very
interesting. Needless to say, my wife found the fact less interesting
Thanks again - hope my rantings are clear enough to decipher
Quote from signalbox.org:
"Although the individual railways in Britain intially developed their own
ideas, harmonisation of signalling principles soon took place, and semaphore
signalling as we know it today was well established by the 1880s. Power
operation of points and signals had arrived by the turn of the century,
although initially only for small signalling schemes. It wasn't until the
1950s that large-scale power signalling came along. The earliest
applications of power signalling simply saw motorisation of existing types
of semaphore signal, but it wasn't long before colour-light signals
There's a whole load of useful stuff on that site. Can't find any dates
Interstingly, not all 'ground signals' are on the ground. They are commonly
called shunting signals and can be full blown semaphores but with different
colours to distinguish them from main signals.
I can't find what dates starting seeing colour light signals introduced but
bear in mind that some lines still have semaphore signalling today so you
could go with semaphore throughout if it is a turn of the century layout!!!
As far as I can tell the illumination was only visible when viewed
square-on, ie from the drivers point of view.
Coloured lights didn't replace semaphores at my local main line station
until it was rebuilt in 1962 so would not affect your layout. I think I read
once that the LNER experimented with coloured lights as early as 1923 so it
would depend on which region of the UK you were modelling? If your purpose
is to model a 'typical' layour of 1870-1925 I suggest you stick to
semaphores. The question then is upper or lower quadrant? :o)
All of the ground based signals in my area were at the top of embankments so
I have no idea what they looked like. (We didn't used to trespass in those
The LNER may have experimented as far back as 1923 but colour lights
certainly didn't become common place at least on the ECML until after
nationalisation. York, for instance, wasn't converted until the 1950s.
Pressed the "send" button too early ....!
The "Oxford Companion to British Railway History" says the following:
Light signals without semaphore arms appeared on the Waterloo & City
railway in 1898. The first daylight colour-light signals in Britain
appeared on the Liverpool Overhead Railway in 1920. In 1922 the
Institution of Railway Signal Engineers set up a committee to consider
three-position signalling, by the time they reported in December 1924 ..
the report principally concerned colour lights. The first four aspect
signalling was installed between Holborn Viaduct and Elephant and Castle
The Southern railway started large scale use of colour light signals fro
m the early 1920's in combination with electrification. On the South
Eastern first where they introduced 4 aspects to allow steam and
electric trains to be better regulated. A little out of your era was the
first mainline to be resignalled throughout, 1933, London to Brighton.
At the time this used a combination of full lever frames down to
miniature types used at Brighton. York on the Eastern region was the
first use of route setting, known as one button route setting, later
superseeded with entrance exit, or NX route setting the standard now.
Latest schemes use automatic route setting using data from timetables,
train describers and rules to determine priority of different trains.
this is turning out to be a science/research fellowship in itself! I am
finding it fascinating to explore all the different issues surrounding the
Thanks heaps for the info ...... I will be looking into this further and
working through what to do, over time
This leads me to my next question and harks back to my earlier statement,
that I am returning after a 30 yr absence
"What's an upper or lower quadrant?"
I know - I know - ignorant newbie! But I 'd rather ask and know, than try to
look cool and continue to be dumb
Imagine the semaphore blade is the hour hand of a clock. (Hand? Remember
when clocks HAD hands? ;) )
An upper quadrant signal has the arm at 3:00 for stop, 1:30 for caution,
12:00 for proceed.
A lower quadrant signal uses 3:00 for stop, 4:30 for caution, and 6:00 for
In the US at least, there were different color lenses on the "spectacle"
(where the blade was mounted) and these also moved to cover a lamp as the
blade moved. Red-stop, Yellow-caution, Green-proceed.
I like semaphores for model railroading. Consider that the place a signal
actually _belongs_ may NOT be front-side visible from all operating
positions - the semaphore is the only signal type readily readable from
the "wrong" side!
A pity there seems to be a lack of working, ready-to-run, semaphore
signals. Did semaphores normally 'rest' in one of the three positions
(stop , caution or proceed)? If so, and using something like memory
wire, it would be convenient to use that as the 'no power' position.
According to C.J. Freezer the signals were weighted in such a way that they
always returned to the safe (stop) position in the event of a mechanical
failure. That included lower quadrant semaphores which were counterbalanced
so as to return to the upper position.
There were exceptions. The NER slotted post lower quadrant signals didn't
always fail safe. There were instances of snow packing into the slot and
preventing the arm returning to danger.
The last of these survived into the (pure guess here) 1980s (at Haxby?) near
York, and was at one time preserved in the concourse of York station.
Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here.
All logos and trade names are the property of their respective owners.