IMPROVEMENTS IN WORKING SEMAPHORE SIGNALS FOR RAILWAYS AND TRAMWAYS, AND IN THE APPARATUS EMPLOYED THEREIN
Year: 1880

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in
the County of Middlesex, Gentleman, for an Invention of " IMPROVEMENTS
IN WORKING SEMAPHORE SIGNALS FOR RAILWAYS AND TRAMWAYS, AND IN
THE APPARATUS EMPLOYED THEREIN." A communication Fom abroad by
Hippolyte Leblanc and Eugène Victor Achille Loiseau, both of Paris, in the
Republic of France.
...
'
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at the
Office of the Commissioners of Patents on the 7th January 1880.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN WORKING SEMAPHORE SIGNALS FOR RAILWAYS
AND TRAMWAYS, AND IN THE APPARATUS EMPLOYED THEREIN." A communica-
tion from abroad by Hippolyte Leblanc and Eugène Victor Achille Loiseau, both of
Paris, in the Republic of France.
This Invention relates to the employment of electricity for the self acting or
automatic working of signals on railways and tramways, and is more particularly
applicable to working the gate signals arranged on what is known as Leblanc's
system for level crossings, the electrical action taking place under conditions which
render it impossible for the apparatus to get out of order.
According to this Invention, during the whole of the time occupied by the train
in travelling over the distance between two fixed points at which the apparatus is
actuated, the signal is maintained in position by certain parts or levers, which are
acted on by the passage of the train. The first of such levers causes the apparatus
to give a signal indicating the approach of a train, whilst the second gives a signal
indicating that the crossing may be traversed in safety by bringing the discs or
shutters back to their normal position.
In order to obtain this result the levers are arranged in combination with an
apparatus which is constructed in such a manner that it actuates the signal imme-
diately when the first wheel of the train comes in contact with and depresses the
lever, which then remains depressed without receiving any shock or vibration
during the passage of the train.
In carrying out this Invention an electrical battery of any suitable description is
employed, the same being placed within or in proximity to the pillar carrying

page_text: signal, and communicating with electro magnets when required through the inter-
vention of apparatus hereinafter described. Two of these electro magnets are
provided on each side of the signal, and each pair of magnets serves to attract or
draw a suitable armature connected to horizontal rods to one side or to the other;
according as the current passes through the magnets on the left, or the magnets on
the right of the said armatures; and each of the borizontal rods is connected at
both extremities to levers suspended at a suitable point and carrying shutters.
When the armature on the right of the signal is attracted by the electromagnet
on the left of the said armature, the armature on the left of the signal will be
drawn to the right, and the shutters will be drawn back in opposite directions, so
as to disclose the danger signal until another electric current acting on the opposite
set of magnets causes them to be drawn forwards in the opposite direction. For
this purpose the armatures are liberated by the electro magnets, whereupon the
shutters fall forwards by their own weight, and swinging after the manner of a
pendulum pass the dead point, causing the armatures to approach the opposite
electro magnets on the right, in which the current is passing at the time.
electro magnets then attract the armatures respectively in opposite directions, and
move the shutters to the position in which they conceal the danger signal, which
has been indicated by the colour of the lantern or by a notice in legible
characters.
These
The shutters are retained in position after the current has ceased to act by means
of a device next hereinafter described.
A bar oscillating on a central point is provided at each extremity with a notch,
in which is fitted one extremity of a bar of soft iron, the other extremity of the
Baid bar of soft iron being jointed to a fixed point. The oscillating bar is sur-
mounted by a spring for facilitating the action.
When the current is passing in one electro magnet one extremity of the bar of
soft iron being attracted by the electro magnet will rise, carrying with it the
corresponding extremity of the notched bar, whereupon the opposite extremity of
the latter will be depressed, together with the corresponding extremity of the
spring by which it is surmounted, as hereinbefore described, so as to cause the
said spring to clear the lower side of the armature, which is then carried over
by the weight of the shutters to the magnet in which the current is passing,
and where it is caught by the opposite extremity of the spring, and retained in
that position after the current has ceased until the passage of a current in the
opposite magnet reverses the positions of the notched lever and of the spring.
The apparatus herein before referred to for working the disc or lamp by electricity
is supported on a plate carrying a spindle, upon which is mounted loosely a disc,
imparting motion to flyers or vanes through the intervention of a train of toothed
wheels driven by a ratchet wheel fast on the spindle carrying the disc. This disc
is provided with two pins, and is connected to an arm or bent lever carrying a
counterweight at one extremity.
The ratchet wheel fast upon the spindle of the disc is actuated by a detent
carried by the disc, which detent is caused to engage with the teeth of the
ratchet wheel by means of a spring for the purpose of actuating the train of toothed
wheels.
One extremity of a horizontal lever oscillating on a centre at the side of the
rail rests upon a heart shaped block jointed to the upper extremity of vertical rod
sliding in guides. The lower extremity of this vertical rod rests upon a spring
fixed to a bracket, and a recess formed in the side of the rod is provided with a
catch acted on by a spring, so as to cause the catch to engage with one of the pins
on the disc during the descent of the rod, as hereinafter described.
When the lever and the parts of the apparatus last hereinbefore described are in
their normal position the first wheel of a passing train will depress the horizontal
lever, and this movement of the lever will in turn depress the vertical rod, causing
it to assume such a position that a notch provided on one side of the rod is brought
opposite to a catch at one extremity of a horizontal rod sliding in two guides

page_text: This horizontal rod is acted on by a spring, so as to cause the catch to engage
with the notch in the vertical rod, and is provided with a pin on its underside.
The descent of the vertical rod raises the arm provided with a counterweight
through the intervention of the catch provided in the recess in the side of the rod,
as hereinbefore described, which catch acts upon the pin on the disc, causing the
latter to perform part of a revolution without moving the train of toothed wheels.
The same motion of the vertical rod depresses the spring by which it is supported,
and this spring then acts upon suitable contact makers in such a manner as to
cause the electric current to act upon the electro magnets, so as to cause them to
move the shutters and display the signal indicating the approach of a train, for
example, as hereinbefore described.
When the train has passed the counterweight at the extremity of the horizontal
lever it will bring this lever back to its normal position, and the arm or bent lever
on the disc will descend gently until the pin on the disc comes in contact with the
pin on the horizontal rod and moves the same, so as to disengage the catch at its
extremity from the notch in the vertical rod, which is then caused to rise suddenly
and resume its normal position by the action of the spring. The movement of the
disc and arm or bent lever is sufficiently slow to allow time for the train to pass
before the vertical rod is liberated, its motion being regulated by the flyers or
vanes hereinbefore referred to, which are set in motion by the detent on the disc
engaging with the ratchet wheel only when the disc is acted on by the arm
carrying the counterweight.
In order to work this apparatus upon a single or a double line of rails it is
arranged as hereinafter described.
In the case of a single line one apparatus for giving signals is placed near the
level crossing. Horizontal levers for causing the apparatus to show the danger
signal or red light are arranged at the side of the rail nearest to the signal, on
each side of the latter at a distance of, say, about 3,300 yards or 2 miles on each
side of the level crossing, and at a distance equal to the length of a train. From
these levers two other levers are provided on the opposite rail for causing the
apparatus to show the white light or safety signal.
When a train comes in contact with and actuates one of the levers for showing
the danger signal it will then pass on to the next lever of the same description,
and lastly over one of the levers for showing the white light, which will then give
a signal indicating that the crossing may be traversed in safety.
In the case of a double line of rails two signal lamps are provided, one on each
side of the level crossing, one being upon the down and one on the up line. Levers
for working the danger signals are provided at a distance of about 2 miles in
advance of each lamp on each line; and at a distance equal to the length of a train
on the other side of the crossing are arranged the levers for the safety signal.
When a train approaches upon the down line, for example, it first comes in contact
with the lever for showing the danger signal, which will continue to be displayed
until the whole of the train has passed over the corresponding lever on the other
side of the crossing for displaying the safety signal, and a similar action will be
effected by the passage of a train upon the up line.
An electric bell may be caused to ring during the period in which the red or
danger signal is displayed.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Henry Johnson in the Great Seal Patent Office on the 6th
July 1880.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN WORKING SEMAPHORE SIGNALS FOR RAILWAYS
AND TRAMWAYS, AND IN THE APPARATUS EMPLOYED THEREIN." A communica-
tion from abroad by Hippolyte Leblanc and Eugène Victor Achille Loiseau, both of
Paris, in the Republic of France.
The said Invention relates to the employment of electricity for the automatic
working of signals on railways and tramways, and is more particularly applicable
to working the gate signals arranged on what is known as Leblanc's system for
level crossings, the electrical action taken place under conditions which render it
impossible for the apparatus to get out of order.
According to the said Invention the signal is maintained at danger during the
whole of the time occupied by the train in travelling over the distance between two
fixed points at which the apparatus is actuated by certain parts or levers which are
depressed or otherwise acted on by the passage of the train. The first of such levers
causes the apparatus to give a signal indicating the approach of a train, whilst the
second subsequently gives a signal indicating that the crossing may be traversed in
safety, the discs or shutters being brought back to their normal position.
In order to obtain this result the said levers are arranged in combination with
an apparatus which is constructed in such a manner that it actuates the signal
immediately when the first wheel of the train comes in contact with and operates
the lever which then remains in the position in which it has been thus placed
without receiving any shock or vibration during the passage of the remaining
wheels of the train.
And in order that the said Invention may be fully understood I shall now pro-
ceed more particularly to describe the same, and for that purpose shall refer to the
several Figures on the annexed Sheets of Drawings, the same letters of reference
indicating corresponding parts in all the Figures.
Figure 1 (Sheet 1) of the accompanying Drawings represents an elevation of the
signal and parts immediately connected therewith, with a portion of the cover
removed; Figure 2 is a plan of the same corresponding to Figure 1, and Figure 3
is an enlarged detail of a portion of the apparatus.
Figure 4 (Sheet 2) is a side elevation of apparatus hereinafter described, to be
placed on the side of the rails; Figure is a corresponding end elevation of the
Bame; and Figure 6 is a plan drawn to a smaller scale, shewing the position of the
apparatus at the side of a line of railway.
Figures 7 and 8 (Sheet 3) are respectively a vertical section and plan illustrating
a modification of the arrangement represented in Figure 6; Figure 9 illustrates a
modification of the apparatus shown in Figures 4 and 5; and Figure 10 is a
sectional elevation drawn to a smaller scale, shewing the manner in which the
apparatus represented in Figure 9 is operated by the wheels of passing trains.
The signal apparatus proper represented in Figures 1 and 2, Sheet 1, is supported
by a pillar or post, and in the usual manner, and is actuated by means of electro
magnets A, A¹, capable of being excited by an electric battery (not shewn in the
Drawings) arranged in proximity to the pillar carrying the signal.
This battery is placed in communication with the electro magnet of A or A¹ when
required through the intervention of the apparatus hereinafter described and
represented in Figures 4 and 5. Two of these electro magnets are provided on
each side of the signal for the purpose of actuating armatures B and B¹ connected
to horizontal rods C, and moving these armatures to one side or the other according
as the current passes through the magnets A or the magnets A¹; each of the rods C

page_text: is connected at both extremities to levers D, suspended at a point a and carrying
shutters E, Figure 1.
When the armature B and B are attracted by the electro magnets A the
shutters E will be drawn back in opposite directions so as to disclose the danger
signal, and will assume the position represented in full lines in Figure 1 until
another electric current acting on the magnets A¹ causes them to be drawn forwards
in the reverse direction; for this purpose the armatures B, B¹, are liberated, where-
upon the shutters E fall forwards by their own. weight, and swinging after the
manner of a pendulum pass the dead point causing the armatures B to approach
the opposite electro magnet A¹ in which the current is passing at the time. These
electro magnets then attract the armatures B, B¹, respectively in opposite directions
and move the shutters E to the position shown by lines and dots in Figure 1,
concealing the danger signal which has been indicated by the colour of the lantern
or by a notice in legible characters.
The shutters are retained in position after the current has ceased to act by
means of a device next hereinafter described.
F (Figure 3) is a bar oscillating on a pin b, which bar is provided at one extre-
mity with a notch capable of engaging with one extremity of a bar G of soft iron,
and at the opposite extremity the bar F is provided with a similar notch capable
of engaging with one extremity of a bar G' also of soft iron, the other extremities
of the said bars G, G, being jointed to fixed points d, d¹, Figure 2. The bar F is
surmounted by a spring H for facilitating the action, as hereinafter described.
When the apparatus is in the position represented by full lines in Figure 3 on a
current being caused to pass into and excite the electro magnet A¹ the bar G¹ will
be attracted by the electro magnet A¹ and move upwards carrying with it the
corresponding extremity of the bar F thereby depressing the opposite extremity of
the latter together with the corresponding extremity of the spring H hereinbefore
referred to so as to cause the said spring to clear the lower side of the armature B.
The armature B being thus released allows the shutters to swing forwards by their
own weight and cover the danger signal, at the same time bringing the armature
within the influence of the magnet A' in which the current is passing, and which
then attracts the armature B and causes it to engage with the opposite extremity
of the spring H so as to be retained in that position after the current has ceased to
pass until the passage of a current in the opposite magnet A reverses the positions
of the lever F and of the spring H.
The apparatus berein before referred to for working the signal disc or lamp by
electricity is supported on a plate K, Figures 4 and 5, carrying a spindle m upon
which is mounted loosely a disc L imparting motion to flyers or vanes M through
the intervention of a train of toothed wheels n driven by a ratchet wheel / fast on
the spindle m. The disc L is provided with two pins i, i¹, and is connected to an
arm or lever K carrying a weight k' at one extremity.
The rachet wheel Z is actuated by a pawl carried by the disc, which pawl is
caused during the descent of the weight k¹ to engage with the teeth of the ratchet
wheel by means of a spring for the purpose of actuating the train of toothed
wheels n.
One extremity of a horizontal lever R, Figure 6, oscillating on a centre at the
Bide of the rails is jointed through the intervention of a connecting rod Z to one
extremity of a rod N sliding in guides p, the connection of the rods Z and N being
indicated at w. The other extremity of the rod N is provided with a friction
roller and bears against a spring P fixed to a bracket 8, and a recess formed in the
side of the rod is provided with a catch a acted on by a spring ¹ so as to cause the
catch to engage with the pin i on the disc.
When the lever R and the parts of the apparatus last herein before described are
in the normal position, the outer edge of the first wheel of a passing train will
push the lever R, and this lever will in turn move the rod N causing it to assume
the position shown in lines and dots in Figure 4, and bringing a notch t provided
on one side of the rod opposite to a catch u' provided at one extremity of a bolt

page_text: or rod sliding in two guides v. The rod Qis acted on by a spring q so as to
cause the catch u¹ to engage with the notch t, and is provided with a pin u capable
of engaging with the pin i¹. The movement of the rod N raises the arm k to the
position indicated by lines and dots in Figure 4 through the intervention of the
catch which acts upon the pin i on the disc L causing the latter to perform part
of a revolution without moving the train of toothed wheels. The same motion of
the rod N pushes back the spring P, and this spring then acts upon contact
makers X in such a manner as to cause the electric current to act upon the electro
magnets A¹ for example, as hereinbefore described, in order to effect the movement
of the shutters E, and the display of the signals indicating the approach of a
train.
When the rod N has moved a certain distance the catch a releases the pin i, and
the lever K on the disc L will descend quietly until the pin i¹ comes in contact
with the pin u on the rod Q, and moves the latter so as to disengage the catch u¹
at its extremity from the notch in the rod N, which together with the lever R is
then caused to suddenly resume its normal position by the action of the spring P.
The movement of the disc L and arm or lever K is sufficiently slow to allow time
for the train to pass before the vertical rod is liberated, its motion being regulated
by the flyers or vanes M which are set in motion by the pawl e¹ on the disc
engaging with the ratchet wheel only when the disc is acted on by the arm k.
When the rod N and spring P return to their normal position the contact
makers X will be separated, and the current will cease to pass to the magnets A¹,
but the signal will remain unaltered as the shutters E will be retained in position
in consequence of the springs H engaging with the armatures B, B', as hereinbefore
described, until the train has passed the crossing and acted upon another similar
apparatus on the other side of the crossing which directs the current to the
opposite set of magnets A, thereby causing a signal to be displayed indicating that
the crossing may be traversed in safety.
In the arrangement illustrated in Figures 7 and 8, Sheet 3, the lever R is bent
80 as to form a bell crank lever which oscillates on a pin y. One arm of this
lever is spread out or flattened at its extremity, so as to present a flat surface z
to the wheel by which it is actuated, and in its normal position is elevated, say,
about one inch above the level of the rail, whilst the other arm is provided with a
fork, by which it is jointed to one extremity of the connecting rod Z. On the
passage of a train the surface comes in contact with and is depressed by the
outer part of the periphery of the first wheel, and the other arm z¹ then operates
an apparatus constructed as herein before described with reference to Figures 4 and 5
through the intervention of the connecting rod z.
Figure 9, Sheet 3, represents an important modification of the apparatus herein-
before described with reference to Figures 4 and 5, according to which modification
the apparatus is actuated by the passing trains by means of a straight lever R
arranged as shown in Figure 10. This lever oscillates on a centre y and has its
centre of gravity on the arm farthest from the rails. One extremity of the lever
is provided with a flat surface z which comes in contact with the outer edge of
the wheels of passing trains, being elevated when in its normal position, say,
about one inch above the level of the rails, and the opposite extremity is provided
with a similar flat surface 21 which bears directly against the under side of the
weight actuating the disc L.
When the extremity of the lever nearest the rails is depressed by the wheels
of a passing train coming in contact with the surface 2, the surface z¹ at the opposite
extremity of the lever will rise and suddenly throw up the weight k', causing the
latter to occupy the position shown by lines and dots in Figure 9. After the
passage of the train the lever R resumes its normal position, and the weight k¹
descends gently, as in the arrangement hereinbefore described with reference to
Figures 4 and 5, until it again rests upon the surface z¹ on the extremity of the
lever. It will be observed that according to this arrangement the rods N and Q
and spring P are dispensed with, the electric current being alternately allowed to

page_text: pass to the inagnets, and intercepted by suitable contact makers actuated by the
lever R.
In applying the apparatus which forms the subject of the said Invention to a
single or a double line of rails, it is arranged in the following manner :-
In the case of a single line one signal post carrying the apparatus, represented in
Figures 1, 2, and 3, is placed near the level crossing levers R for causing the
apparatus to show the danger signal or red light, are arranged at the side of the
rail nearest to the signal on each side of the latter, at a distance of, say, about
three thousand three hundred yards, or two miles on each side of the level crossing,
and at a distance equal to the length of a train; from these levers two other levers
are provided on the opposite rail for causing the apparatus to shew the white light
or safety signal, that is to say, the distance between the two levers for showing
the red light or danger signal is equal to about four miles, plus the width of the
crossing, and the distance between the two levers for showing the white light or
safety signal is equal to about four miles, plus the width of the crossing, plus the
length of two trains.
When a train comes in contact with and actuates one of the levers for showing
the danger signal it will then pass on to the next lever of the same description;
and, lastly, over one of the levers for shewing the white light, which will then give
a signal indicating that the crossing may be traversed in safety.
In the case of a double line of rails two signal posts are provided, one on each
side of the level crossing, one being upon the down and the other on the up line.
Levers for working the danger signals are provided at a distance of about two
miles in advance of each signal post on each line, and at a distance equal to the
length of a train; on the other side of the crossing are arranged the levers for the
safety signal. When a train approaches upon the down line, for example, it first
comes in contact with the lever for showing the danger signal, which will continue
to be displayed until the whole of the train has passed over the corresponding lever
on the other side of the crossing for displaying the safety signal, and a similar
action will be effected by the passage of a train upon the up line.
The distance between the two levers for shewing the red or danger signal is
about four miles, plus the width of the crossing, and the distance between the two
white or safety signals is equal to the length of two trains, plus the width of the
crossing. An electric bell may be caused to ring during the period in which the
red or danger signal is displayed.
Having now described and particularly ascertained the nature of the said
Invention, and the manner in which the same is or may be used or carried into
effect, I would observe in conclusion that what I consider to be novel and original,
and therefore claim as the Invention secured to me by the hereinbefore in part
recited Letters Patent is,-
First. The employment of a combination of levers operated by passing trains
for the purpose of locking or retaining for a given period the parts of an apparatus
which during the limited period for which they are so retained afford a passage for
an electric current acting in turn upon a disc or shutter by means of one or more
electro magnets so as to cause such disc or shutter to assume a determined position
and remain in such position until the train comes in contact with and actuates
another lever, thereby causing the disc or shutter to return to its normal position,
all substantially as hereinbefore described.
Secondly. The mode of effecting the connection between the lever, acted, on by
the train and mechanism or apparatus which locks the said lever instantly on the
passage of the first wheel of the train, the locking continuing for a given period
so as to allow the train to pass without the remaining wheels coming into contact
with the lever during their passage, thereby avoiding any vibration of the lever or
apparatus, substantially as herein before described.
Thirdly. The employment of electricity for acting on the discs or shutters of
signals by means of combinations of parts establishing a perfect electric contact for

page_text: a given period, substantially as hereinbefore described and illustrated in Figures
4, 5, 6, 7, 8, 9, and 10 of the Drawings.
Fourthly. The employment of electric action to move shutters arranged according
to what is known as Leblanc's system, after the manner of a pendulum, substan-
tially as hereinbefore described and illustrated in Figures 1, 2, and 3 of the
Drawings.
In witness whereof, I, the said John Henry Johnson, have to this my
Specification set my hand and seal, this Sixth day of July, One thousand
eight hundred and eighty.
J. HENRY JOHNSON. (L.S.)