IMPROVEMENTS IN SIGNALS
Year: 1853

page_text: LETTERS PATENT to Thomas Bouch, of Edinburgh, in the County
of Mid-Lothian, North Britain, Civil Engineer, for the Invention
of "IMPROVEMENTS IN SIGNALS."
PROVISIONAL SPECIFICATION left by the said Thomas Bouch
at the Office of the Commissioners of Patents, with his Petition,
on the 22nd March 1853.
I, THOMAS BOUCH, of Edinburgh, in the County of Mid-Lothian,
North Britain, Civil Engineer, lo hereby declare the nature of the said
Invention for "IMPROVEMENTS IN SIGNALS" to be as follows :—
This Invention relates to the so constructing and arranging such
signals as are in use on railways and in other situations that they may
work with increased efficiency, and afford more satisfactory indications
of safety or the reverse than at present. In fitting up such a signal as
is used at a railway station, or on a curve, a main post of the usual
kind is erected, with or without a lamp on its apex, and to this post,
near the top, is firmly fixed a circular disc with a red face (for

page_text: example) facing the direction from which the trains come. Then
alongside this post is the usual vertical parallel rod of iron, arranged to
turn in suitable bearings, and fitted near its lower end with a projection
bearing upon a fixed spiral guide piece or inclined plane,-a screw of
coarse pitch, for example: so that as the rod is turned in either direc-
tion the traverse of the pin over the spiral will cause the rod to rise or
fall vertically in its bearings. Near the top of this rod, which is also
surmounted by a red lamp, is a duplex signal disc arrangement, com-
pounded of discs of two very different shapes, as circular and square.
The upper disc is a circular one, and it stands in such a position that
when the signal rod is at its starting point indicating a clear road, for
instance, it presents a white face to the engine driver, and covers up
the fixed disc on the post behind entirely from view. The lower disc,
which may be square, is set at right angles to this upper one, into
which it is entered, or as it were mortised, half through from the lower
edge. In this position, then, the square signal presents its edge to the
driver. Now if the signal man wants to indicate caution," or
danger," he turns the rod a quarter round, and this, of course, brings
the circular white-faced disc with its edge towards the driver, and the
revolution brings the green face of the square disc into view, covering
up the fixed red disc behind it as the spiral action below forces it
up to coincide with the level of the latter disc. The lamp and upper
disc are also correspondingly carried up, so that a clearly distinct signal
is formed. Again, if the driver is to stop, the signal man turns the
rod another quarter round, when the spiral action carries up the front
lamp quite above and clear of the fixed one behind, and at the same
time shifts the upper circular disc above and clear of the fixed red
disc behind it, bringing the red face of this moveable disc with its
original face side towards the driver, whilst the square disc presents its
edge. Hence the driver now sees two clear outlines of lamps and discs
in red.
This arrangement is obviously capable of many modifications, keep-
ing in view the essential feature of presenting distinctive forms com-
bined with distinctive colors to produce a plainly perceptible signal.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Bouch, in the Great Seal Patent
Office, on the 22nd September 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
THOMAS BOUCH, of Edinburgh, in the County of Mid-Lothian, North
Britain, Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-second day of March, in the
year of our Lord One thousand eight hundred and fifty-three, in the
sixteenth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Thomas Bouch, Her special licence
that I, the said Thomas Bouch, my executors, administrators, and
assigns, or such others as I, the said Thomas Bouch, my executors,
administrators, or assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
SIGNALS," upon the condition (amongst others) that I, the said Thomas
Bouch, by an instrument in writing under my hand and seal, should
particularly describe and ascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the
same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Thomas Bouch, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement, reference being had to the accompanying
drawings, and to the letters and figures marked thereon, that is to
say:
My said Invention relates to the so constructing and arranging such
signals as are in use on railways, and in other situations where pro-

page_text: minent distinguishing marks are necessary, that they may work with
increased efficiency, and afford more satisfactory indications of safety
or the reverse than has hitherto been the case. In fitting up such
a signal as is used at a railway station, or on a curve, a main post of
the usual kind is erected, and to this post, near the top, is firmly fixed
a circular disc with a red face (for example) facing the direction from
which the trains come. Then alongside this post is the usual vertical
parallel rod of iron arranged to turn in suitable bearings, and fitted near
its lower end with a projecting arm bearing upon a fixed spiral guide
piece or inclined plane,-a screw of coarse pitch, for example; so that as
the rod is turned in either direction the traverse of the projecting arm
over the spiral will cause the rod to rise or fall vertically in its bear-
ing. Near the top of this rod, which is also surmounted by a red
lamp, is a duplex signal disc arrangement, compounded of dises of two
very different shapes, as circular and square. The upper dise is a
circular one, and it stands in such a position that when the signal rod
is at its starting point indicating a clear road, for instance, it presents
a white face to the engine driver, and covers up or conceals the fixed
dise on the post behind entirely from view. The lower disc, which
may be square, is set at right angles to this upper one.
In this posi-
tion, then, the square signal presents its edge to the driver.
Now
if the signal man wants to indicate "caution." he turns the rod a
quarter round, and this, of course, brings the circular white-faced dise
with its edge towards the driver, and the revolution brings the green
face of the square disc into view, covering up the fixed red disc behind
it, as the spiral action below forces it up to coincide with the level of
the latter disc. The lamp and upper disc are also correspondingly
carried up, so that a clearly distinct signal is formed. Again, if the
driver is to stop, the signal man turns the rod another quarter round,
when the spiral action carries up the upper ercular disc above and
clear of the fixed red disc behind it, bringing the red face of this move-
able disc with the red lamp fixed upon it towards the driver, whilst the
square disc presents its edge. Ilence, the driver now sees two clear out-
lines of lamps and discs in red. This arrangement is obviously capable

page_text: of many modifications, keeping in view the essential feature of pre-
senting distinctive forms combined with distinctive colours to produce
a plainly perceptible signal.
Figure 1, on my sheet of drawings, is a front elevation of a signal
of my improved construction, as arranged in its primary position, pre-
senting a plain white disc to the view of the engine, indicating that the
line is clear, and, therefore, that the train may safely proceed. Figure 2,
is a corresponding side view of the signal at right angles to Figure 1,
with all the parts in a corresponding position, so as to produce the same
signal as that indicated in Figure 1. Figure 3, is a detached front
view of the actual signal portion alone, showing the indicating appa-
ratus in its second position, to show that a passing train must proceed
with caution, a square green disc being displayed for this purpose.
Figure 4, is a similar detached view of the disc-signalling details,
wherein two distinct red discs are exhibited to indicate danger.
Figure 5, is a plan of the entire signal apparatus, corresponding to the
positions of the several parts, as delineated in Figures 1, and 2.
The signal is constructed in its general details on the same plan as
the common apparatus. It consists of a stout wooden pillar A, carrying
horizontal side brackets B, in which brackets are plain eyes to receive
the parallel vertical iron rod C. This main post A, is fitted with a
ladder D, and platform E, in the usual way, for the ascent of the signal
man; and its inner front face carries a stationary circular disc F, with a
red face, pointing in the reverse direction to the train's motion.
The long adjusting rod C, is passed freely through its plain eyes in the
brackets B; having liberty both to rotate and traverse longitudinally
therein; a collar G, being on the lower end of the rod to prevent it
from traversing too high at any time. This rod is surmounted by a
circular signal disc H, coloured white on
and red on the other, as in Figure 4.
carries a second disc I, of a square or
or half entered into the upper disc II, forming one piece with it. These
details, with the ordinary lamp J, on the apex of the rod C, form the
entire signalling apparatus. The front face of the timber post A, has
one side, as shewn in Figure 2,
Beneath this disc the rod also
rectangular shape, and checked

page_text: also bolted to it, lower down, a spiral guide piece, or curved incline K,
held at its two ends L, in a fixed position. This spiral piece embraces
the rod C. and an adjustable arm M, standing out at right angles from
the rod, carries a small pulley N, upon its outer end, bearing upon the
edge of the incline as a support, a small handle o, being fitted up with
a catch, as shewn in dotted lines, for manual adjustment; or when the
signal is to be actuated from a distance by cords or ropes in the usual
way, the common signal wire rope is passed round the pulley P, keyed
on near the lower end of the rod A. An additional lamp Q, may be
attached to the red face of the upper disc II. as a security against
danger arising from colour blindness, or an inability fairly to distin-
guish different colours. When the signal is in its first position, as
delineated in Figures 1, 2, and 5. the circular disc having its white face
towards the approaching train completely covers or conceals the fixed
red disc F, on the wooden pillar from view, whilst the green dise I,
being turned with its edge towards the coming train, is also invisible.
Under these circumstances, then, the engine driver seeing only the white
face, or a single round disc, knows that the line is clear for his journey.
But if from any cause "cantion" is to be signalled, the signal man, either
by his wire rope and pulley P, or the adjusting handle o, turns the
rod C. one quarter round upon its axis. Then, as the arm M, is fast on
the rod C, it goes round with it, and in the traverse of the pulley N, over
the incline K, the rod C, is caused to rise up through its bracket bear-
ings, so as to bring the signal dises into their second position, as repre-
sented in Figure 3. The circular red and white faced disc is now
turned with its edge towards the train, and is therefore invisible, whilst
the rectangular green dise I, faces the train, and covers up or conceals
the fixed red disc F, entirely from the driver's view, so that as the look-
out on the train sees only the green disc, he at once knows that he must
run slowly, and with care. If "danger" is to be signalled for the pur-
pose of stopping the train, the signal man turns the rod C, another
quarter round; the resulting traverse of the arm M, over the spiral
guide K, carries the rod still further upwards in its bearings, bringing
the signal discs into their third position, Figure 4. The circular

page_text: disc H, having thus been turned a full half round, now presents its red
face towards the train, and its increased elevation, due to the spiral
guide action, having brought it to a higher level than that of the
stationary disc F, the engine driver now sees two separate red-faced
lises, of circular shape, forming a very striking "stop" signal. On re-
versing the action of the rod C, the discs are obviously brought back
into their normal position, as in Figures 1, 2, and 3.
For night work the lamp signals will act in this manner-In the
first position the lamp J, on the top of the rod C, will give a white light
indicating "all clear," whilst the lower or secondary lamp Q, is screened
by the circular disc H. In the second position, when the rod C, is
turned one fourth round, the upper lamp J, has a new branch brought
forward to throw out a green light indicating "caution;" the secondary
lamp Q, being still shaded. In the third position the third branch of the
compound lamp J, will give out a red light, whilst the single secondary
lamp Q, is now brought to bear, and gives a similar red light, both in
the direction of the approaching train. In this case, should the look-
out be affected with colour blindness, he will yet be put on his guard
by the appearance of two distinct lights indicating danger.
Having now described and particularly ascertained the nature of my
said Invention, and the manner in which the same is or may be used
or carried into effect, I may observe, in conclusion, that I do not confine
or restrict myself to the precise details or arrangements which I have
had occasion to describe or refer to, as many variations may be made
therefrom without deviating from the principles or main features of my
Invention; but what I consider to be novel and original, and therefore
claim as the Invention secured to me by the herein-before in part
recited Letters Patent, is,-
First, the general arrangement and construction of signals, as herein-
before described.
Second, the system or mode of combining outline or shape with
colour for signalling purposes, as herein-before described.
Third, the application and use in railway signals of adjustable or
shifting discs for the production of variable combinations of form and
colour, as herein-before described.

page_text: Fourth, the application and use of scroll or inclined traversers for
the clevation and depression of signal discs.
In witness wherof, I, the said Thomas Bouch, have hereunto
set my hand and seal, this Nineteenth day of September, in the
year of our Lord One thousand eight hundred and fifty-three.