IMPROVEMENTS IN SIGNALLING ON RAILWAY TRAINS, AND IN THE MECHANISM AND APPLIANCES THEREFOR
Year: 1872

page_text: LETTERS PATENT to Edward Gilbert, of the City and County of
Edinburgh, North Britain, Telegraph Engineer, for the Invention of
"IMPROVEMENTS IN SIGNALLING ON RAILWAY TRAINS, AND IN THE MECHANISM
AND APPLIANCES THEREFOR.”
Sealed the 22nd October 1872, and dated the 11th June 1872.
PROVISIONAL SPECIFICATION left by the said Edward Gilbert at the
Office of the Commissioners of Patents, with his Petition, on the
11th June 1872.
I, EDWARD GILBERT, of the City and County of Edinburgh, North
Britain, Telegraph Engineer, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN SIGNALLING ON RAILWAY TRAINS, AND IN THE
MECHANISM AND APPLIANCES THEREFOR," to be as follows, that is to say:-
The object of this Invention is to provide an improved and facile
means of communication by audible and visible signals between the
passengers and the servants in charge of trains on the one hand, and
between the said servants themselves on the other hand, and simul-
taneously with the transmission of such signals to introduce a tell-talo
A

page_text: or indicator that will show from which compartment of a train of
carriages a communication emanated; also an improved means of
affording instant intimation to the servants of the separation whilst in
motion of any portion of a train, all by the agency of electric currents
and more simple apparatus or mechanism, and movements thereof on
the part of the passengers and servants, while more certain action and
less liability to derangement than has been the case with railway train
signalling apparatus heretofore used are obtained.
And the nature and novelty of this Invention consist substantially all
as follows (though susceptible of slight modifications in its application
to suit particular cases and circumstances, without diverging from the
essential features thereof), namely, that is, by these improvements the
alarm and intelligible signals are communicated or made by electric
currents through a single line of telegraph wire placed and connected
throughout the entire train of carriages.
The line of wire may consist of a single or any number of strands of
copper, and be insulated in the usual manner by a coating of gutta
percha, or india rubber, or both, and with an external wrapping of tape
For-platted-hemp-saturated_with_tar,_or_paint, or other protecting
material, the permanent parts being placed by preference in a concealed
or enclosed space along the side, roof, or below the floor of each carriage,
directly attached or soldered at each end to metallic flanged socket
coupling pieces, which are firmly secured by screws and an insulating
layer of ebonite or other equivalent to the outside of each carriage, van,
and engine, near each end and by preference near the top, so that the
prepared portable coupling piece of similarly insulated wire, strongly
protected with a flexible covering, as platted strands of tarred or painted
hemp or other equivalent, may be casily and simply connected or
coupled to the said socket parts by metallic connecting parts, or plug or
stem end coupling picces, firmly soldered and otherwise secured to the
ends of the portable coupling wires, which are so long and loose as to
allow the carriages to move to and from each other by their drawing
chains and springs. The sockets and stems of these improved fixed and
loose couplings respectively are preferred to be cylindrical with a flat side
having a vertical transverse round hole bored though both, into which a
loose fixing pin, secured by a short chain to the fixed socket part of each
coupling, or to the framework of the carriage near it, is inserted by
land when the stem ends of the portable parts of the connecting wire

page_text: arc inserted into the sockets, and thus firmly secure them so that they
cannot be detached without removing one of the said pins.
For the engines the simple socket and pin connections of the wires,
as described, are considered sufficient, but for the ordinary and slip or
detachable vans and carriages the fixed socket parts are made duplex,
the actual socket part being attached by a strong square stem, which is
made to slide in a corresponding recess in the fixed flanged piece screwed
to the side of the carriage. The connection of these two parts is formed
by a slot in the outer recessed part and a pin working in it screwed into
the square stem, and also by a blade spring on one side, with either one
or two lateral catch projections worked by the spring through the side
of the socket into transverse recesses in the square stem, or into that
and the end stem of the portable coupling wires also, which sliding
coupling arrangement allows the end of the square stem, when pressed
in or drawn out respectively, to break, or make the metallic contact
between the main line wire and fixed socket part, and a wire to carth,
having metallic contact through the axle or bush, the upper end of the
said earth wire being attached to an insulated screw pin and sliding
spring make and break contact stud, secured to each fixed part of these
couplings, and thus the end of the square stem pushes it from or allows
it to have metallic contact with the fixed coupling part, so that the
drawing out of the secondary socket part which the blade springs hold
in position, makes the connection with the earth wire; and the strain of
breaking any one of the coupling pieces of the main wire would also
make the earth connection, and thus set the alarm or trembling bell in
action at both ends of a train.
At each end of the train, in the ordinary vans, or slip van, and on the
engines, where the servants and engineman in charge of the train are,
any of the ordinary well-known constructions of good constant batteries
used for electric purposes is placed, having one of its poles directly
connected by a wire to one or more of the axles or their bushes for the
earth connection, the other pole of the battery being connected to the
permanent part of the main line or wire, through a somewhat new or
improved simple arrangement of alarm trembling and signal bell com-
bined with a galvanometer or indicating needle with their electric coils,
all contained within a small flat box screwed intermediately between the
battery and main line, by preference against a convenient side of the
van or engine, but having its front lid (with glass for seeing the action

page_text: of the needle through) made to open on hinges, and secured from
being tampered with by a simple lock, the key of which would be in the
possession of the guard; the last round wire from the battery being
also connected through a "silent" or small make and break contact
turn spindle inside, with handle outside the box to put the battery
current on or off, and make and break the connection with the bell coil.
The wire from the galvanometer coil is connected through a fixing screw
terminal to the main line wire passing through the van or engine, as the
case may be, which is fitted with a metal "switch" or spring lever
connected with a reciprocating spindle, passing out through the top part
of the box with a finger knob on it, so that when pushed down as a
" switch" or commutator key, the lever touches a fixing screw or
terminal below it, with a wire connecting it with the earth through the
axles of the van or engine, or their bushes, and thus make the bell
tremble and ring constantly, or vibrate at any desired intervals or single
strokes, according as the knob is held down, or only pressed down at the
desired intervals or times, to give the number of rings required to
indicate the words or signal to be given or communicated between the
servants manipulating or working the operating apparatus at each end
-or-part-of-the-train-where-these_and_the_servants are, and the action of
the indicating needle at once shows the operator whether the connections
are all made and the batteries and commutator are working properly.
The new simple mechanical arrangement (which is placed in every
passenger carriage or compartment of a carriage for closing the electric
circuit at the will of the passenger, and setting in action the alarm or
trembling bell) consists of a small bollow box made of wood or metal
(by preference round), the front part opening on a hinge on the back
part, screwed to the side of the compartment of a carriage high enough
to be out of the way of accidental interference, but capable of being
reached to push in a central stem with a large head or knob for the
purpose, with the word "push" engraved on it in large legible letters, and
which when pushed in works a spring switch catch inside, so as to make
contact between the main line wire and the earth wire from this instru-
ment. The central stem or alarm stud works out through a hollow metallic
socket and white disc, with one or more equal segmental parts cut out
through it, all protected by a glass secured in an outer ring or bizzle.
A loose disc is made to revolve inside the white disc to the extent of the
segmental parts cut away in the stationary front disc, in its normal

page_text: position, showing the parts of its face exposed through the front disc,
white also, with the words "to warn the guard" printed legibly in one
space. The pushing in of the central stem (as stated) by a lateral pin
working through a straight slot in its guiding socket, takes into an
inclined or spiral groove in the eye of the loose inner disc so as thus to
turn it, and show the red or danger colored segments through the
segmental openings in the outer disc, showing also the words "the guard
is warned," where it showed the notice "to warn the guard" before, all
against the power of a lateral acting spring tending to pull the loose
disc and stud back to their normal position when let go, or unlocked
after being pushed in to warn the guard. The back part of this new
guard warning apparatus has two metallic screw terminal studs, ono
directly connected by a wire to the main line wire passing through the
carriage, while the other screw conducts to earth by a wire to the axle
of the carriage or its bush. The latter stud is in metallic contact with
a small metallic bracket carrying a radially sliding spring switch catch
with a lateral stud, which when permitted to go towards the centre,
makes metallic contact with the first terminal stud connected by a wire
to the main line; but when the box is closed and locked by a radial spring
lock and the central pushing stud in its normal outer position, its inner
end keeps the said radially sliding spring switch or catch out of contact,
but when the knob or stud is pushed in, the end of the said catch slips
into a notch cut for it in the side part of the spindle of the central
pushing stem, so as to make the metallic connection with the earth
through the switch catch of this signalling apparatus so pushed in by
the passenger. The spindle and signal or tell-tale disc being also thus
fixed in the signalled position by the end of the said radially acting
spring catch, which then sets on the trembling bell at both ends of the
train, and thus indicates to the guard and engineman that a signal has
been given by a passenger in some compartment of the train, when the
guard can see from the dial of the signal apparatus the exact com-
partment in which the signal was given. However, the mechanical
action of the passenger pushing in the central stem may also be made to
push out a signal board or other equivalent in the particular carriage,
which could be seen by the servants from either end of the train when
this was desired. The guard alone, by a small simple spindle key, with
a fine thread on its extreme end, can insert and screw it into a corre-
spondingly screwed hole in the radial catch, so as to free the acting
spindle and allow it and all the other parts to assume their normal

page_text: position again by the action of their respective springs, the same key
answering to enter another small radial hole in the box, to release its
locking catch when it is desired to inspect or repair the internal
mechanism.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Edward Gilbert in the Great Scal Patent Office
on the 10th December 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
GILBERT, of the City and County of Edinburgh, North Britain,
Telegraph Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eleventh day of June, in the year of
our Lord One thousand eight hundred and seventy-two, in the thirty-
fifth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Edward Gilbert, Her special licence that
I, the said Edward Gilbert, my executors, administrators, and assigns, or
such others as I, the said Edward Gilbert, my executors, administrators,
and 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 SIGNALLING ON
RAILWAY TRAINS, AND IN THE MECHANISM AND APPLIANCES THEREFOR," upon
the condition (amongst others) that I, the said Edward Gilbert, my
executors or administrators, by an instrument in writing under my, or
their, or one of their hands and seals, 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 Edward Gilbert, do hereby declare
the nature of my said Invention, and in what manner the same is to be

page_text: following statement in writing, reference being had to the accompanying
Drawings, and to the letters and figures marked thereon, that is to say :-
The object of my said Invention is to provide an improved and facile
means of communication by audible and visible signals between the
passengers and the servants in charge of trains on the one hand, and
between the said servants themselves on the other hand, and simul-
tancously with the transmission of such signals to introduce a tell-tale
or indicator that will show from which compartment of a train of carriages
a communication emanated; also an improved means of affording instant
intimation to the servants of the separation, whilst in motion, of any
portion of a train, all by the agency of electric currents, and more simple
apparatus or mechanism and movements thereof on the part of the
passengers and servants, while more certain action and less liability to
derangement than has been the case with railway train signalling
apparatus heretofore used are obtained.
And the nature and novelty of my said Invention and improvements
consist substantially all as follows:-Although as will be evident to the
practical engineer and electrician, these are susceptible of considerable
modifications in their application to suit particular cases and circumstances
without diverging from the essential features of the Invention.
The alarm and intelligible signals are communicated or made by
electric currents through a single line of telegraph wire placed and con-
nected throughout the entire train of carriages.
The line of wire may consist of a single or any number of strands of
copper, and be insulated in the usual manner by a coating of gutta
percha or india-rubber or both, and with an external wrapping of tape
or platted hemp saturated with tar or paint or other protecting material,
the permanent parts being placed by preference in a concealed or enclosed
space along the side, roof, or below the floor of each carriage, directly
attached or soldered at each end to metallic flanged socket coupling
picces, which are firmly secured by screws and an insulating layer of
ebonite or other equivalent in a suitable position on the outside of each
carriage, van, and engine, preferably at or near each end and near the top
or at such a lower height, so that the prepared portable coupling pieces
of similarly insulated wire strongly protected with a flexible covering,
as platted strands of tarred or painted hemp or other equivalent, may
be easily and simply connected or coupled to the said socket parts by

page_text: metallic connecting parts or plug or stem end coupling picces, firmly
soldered and otherwise secured to the ends of the portable coupling
wires, which although so long and loose as to allow the carriages to move
to and from each other by their drawing chains and springs, are kept
clear of the drawing chains and couplings. The sockets and stems of
these improved fixed and loose couplings respectively are preferred to be
cylindrical with a flat side having a vertical transverse round hole bored
through both, into which a loose fixing pin secured by a short chain to
the fixed socket part of each coupling or to the framework of the carriage
near it, is inserted by hand when the stem ends of the portable parts of
the connecting wire are inserted into the sockets, and thus firmly secure
them so that they cannot be detached without removing one of the said
pins.
For the engines the simple socket and pin connections of the wires, as
described, are considered sufficient, but for the ordinary and slip or
detachable vans and carriages, the fixed socket parts are made duplex,
the actual socket part being attached by a strong square stem, which is
made to slide in a corresponding recess in the fixed flanged piece screwed
to the carriage. The connection of these two parts is formed by a slot
in the outer recessed part and a pin working in it, screwed into the
square stem, and also by a blade spring on one side with either one or
two lateral catch projections worked-by-the-spring-through-the-side-of-
the socket into transverse recesses in the square stem, or into that and
the end stem of the portable coupling wires also, which sliding coupling
arrangement allows the end of the square stem, when pressed in or drawn
out respectively, to break or make the metallic contact between the
main line wire and fixed socket part and a wire to earth, having metallic
contact through the axle or bush, the upper end of the said earth wire
being attached to an insulated screw pin and sliding spring make and
break contact stud secured to each fixed part of these couplings, and
thus the end of the square stem pushes it from or allows it to have
metallic contact with the fixed coupling part, so that the drawing out of
the secondary socket part which the blade springs hold in position makes
the connection with the carth wire, and the strain of breaking any one
of the coupling pieces of the main wire would also make the earth con-
nection, and thus set the alarm or trembling bell in action at both ends
of the train.
At each end of the train in the ordinary vans or slin van and on the

page_text: "
engines where the servants and engineman in charge of the train are,
any of the ordinary well-known constructions of good constant batteries
used for electric purposes is placed, having one of its poles directly con-
nected by a wire to one or more of the axles or their bushes for the
earth connection, the other pole of the battery being connected to the
permanent part of the main line or wire, through a somewhat new or
improved simple arrangement of alarm trembling and signal bell com-
bined with a galvanometer or indicating needle with their electric coils,
all contained within a small flat box screwed intermediately between the
battery and main line, by preference against a convenient side of the
van or engine, but having its front lid (with glass for seeing the action
of the needle through) made to open on hinges and secured from being
tampered with by a simple spring catch lock, the key of which would be
in the possession of the guard; the last named wire from the battery
being also connected through a 'silent" or small make and break
contact turn spindle inside, with handle outside the box to put the
battery current on or off, and make and break the connection with the
coils of the electric bell. The wire from the galvanometer coil is con-
nected through a fixing screw terminal to the main line wire passing
through the van or engine, as the case may be, which is fitted with a
metal "switch" or spring lever connected with a reciprocating spindle
passing out through the top part of the box with a finger knob on it, so
that when pushed down as a
switch" ог "commutator" key the lever
touches a fixing screw or terminal below it with a wire connecting it
with the earth through the axles of the van or engine or their bushes,
and thus make the bell tremble and ring constantly or vibrate at any
desired intervals or single strokes, according as the knob is held down
or only pressed down at the desired intervals or times to give the number
of rings required to indicate the words or signal to be given or com-
municated between the servants manipulating or working the operating
apparatus at each end or part of the train where these and the servants
are, and the action of the indicating needle at once shows the operator
whether the connections are all made and the batteries and commutator

page_text: "
(by preference round), the front part lifting off or opening on a hinge on
the back part which is screwed to some part of the inside of each
compartment of the carriage, high enough to be out of the way of
accidental interference, but capable of being reached to push in a central
stem with a large head or knob for the purpose, with the word "push
engraved on it in large legible letters; and which when pushed in works
a spring switch catch inside so as to make contact between the main line
wire and the earth wire from this instrument. The central stem or
alarm stud works out through a hollow metallic socket and white disc
with one or more equal segmental parts cut out through it, all protected
by a strong glass secured in an outer ring or bizzie. A loose disc is
made to revolve inside the white disc to the extent of the segmental
parts cut away in the stationary front disc; in its normal position
showing the parts of its face exposed through the front disc, white also,
with the words "to warn the guard," printed legibly in one space. The
pushing in of the central stem (as stated) by a lateral pin working
through a straight slot in its guiding socket, takes into an inclined or
spiral groove in the eye-of the loose inner disc so as thus to turn it and
show the red or danger colored segments through the segmental openings
in the outer disc where it showed the white, also the words "the guard
-is-warned,"_where it showed the notice "to warn the guard" before, all
against the power of a lateral acting spiral or other spring-tending-to-
pull the loose disc and stud back to their normal position when let go, or
unlocked after being pushed in to warn the guard. The back part of
this new guard warning apparatus has two metallic screw terminal
studs, one directly connected by a wire to the main line wire passing
through the carriage, while the other screw conducts to earth by a wire
to the axle of the carriage or its bush. The latter stud is in metallic
contact with a small metallic bracket carrying a radially sliding spring
switch catch with a lateral stud; which when permitted to go towards
the centre makes metallic contact with the first terminal stud connected
by a wire to the main line; but when the box is closed and locked by a
radial spring lock, and the central pushing stud in its normal outer
position, its inner end keeps the said radially sliding spring switch or
catch out of contact, but when the knob or stud is pushed in, the end of
the said catch slips into a notch cut for it in the side part of the spindle
of the central pushing stem so as to make the metallic connection with
the earth through the switch catch of this signalling apparatus so pushed
in by the passenger. The spindle and signal, or tell tale disc being also

page_text: thus fixed in the signalled position by the end of the said radially acting
spring catch, which then closes the circuit to each end, and sets on the
trembling bell at both ends of the train, and thus indicates to the guard
and engine driver that a signal has been given by a passenger in some
compartment of the train; when the guard can see from the dial of the
sigual apparatus the exact compartment in which the signal was given.
However the mechanical action of the passenger pushing in the central
stem may also be made to push out a signal board or other equivalent in
the particular carriage which could be seen by the servants from either
end of the train when this was desired. The guard alone by a small
simple spindle key with a fine thread on its extreme end can insert and
screw it into a correspondingly screwed hole in the radial catch so as to
free the acting spindle and allow it and all the other parts to assume their
normal position again by the action of their respective springs, a similarly
constructed key but varied in size, answering to enter another small
radial hole in the box to release its locking catch when it is desired to
inspect or repair the internal mechanism.
And in order that my said Invention, and the manner and means of
performing it may be thoroughly understood, I shall now proceed to
describe the several Figures on the Sheet of Drawings, which I have
hereunto appended for the purpose of showing the best modifications and
means I am at present aware of for practically carrying the Invention
into effect or practice, the same reference letters and numerals indicating
the same or like parts in the several Figures.
Figures 1 and 2 are front elevations of the passenger "communicator"
or signalling instrument A, A', for calling the attention of or alarming
the guard and engine driver at each end of the train 1, 2, through the
needle indicating galvanometer and alarm bell or instrument B, placed
in the vans or on the engine at each end of the train, all connected by a
main line wire L, L, L', throughout the train, each instrument also
having a wire E connected to it leading to earth, through the axles and
wheels F of their respective carriages. The connection of these wires,
and the construction and action of the instruments A, B, will herein-
after be more fully described.
Figure 1 shows the brass knob a in its outward position through the
centre of the glass_ 6', and outer dial c, preferably flush with it, but it
might be projecting beyond when desired, with the word "pushı”

page_text: engraved in large black letters on it, and having the inner revolving
reciprocating dial d, also in its normal position, showing the white
divisions d¹ through the segmental spaces c³ of the outer face c, with the
words "to warn the guard" shown in the lowest division c", while
Figure 2 shows the knob a pushed in, and the red spaces d¹¹ of the inner 5
dial & turned so as to show through the said spaces c' of the outer face c,
with the words "the guard is warned" shown through the said lower
operture c¹¹.
Figure 3 is a front elevation of the " communicator "A, A', correspond-
ing to Figures 1 and 2, but with the enclosing cap b, glass 6', and outer 1
face c shown as unlocked, and turned quite open on its hinge 6", securing
it to the wooden sole or body A', all so as to show the working dial d
with its face divided into the three white and three red cqual sized
segmental spaces d', d", respectively.
b
Figure 4 shows a face view with the cap 6 turned up on edge, showing 1
the hole b* for inserting its locking and unlocking key /', and the moving
disc d indicated as cut away to show the internal construction and
arrangement of the parts more clearly in the position corresponding to
Figure 1 and Figure 5 is a transverse section through the centre of
the instrument corresponding to Figure 2, showing the knob a as pushed 2
in, and the connection made through-the-instrument. A with the main
line wire L to the earth wire E, thus dividing and completing the circuit
to both ends 1 and 2 of the train through the alarm instruments B, B',
placed there.
Figure 6 is a transverse section of the new or improved needle 2
indicating and alarm instrument B, B', secured in any convenient
position in the end vans H, and on the engine H¹ or tender H", all
connected by one main line wire L throughout the train, each of these
instruments B, B', having a wire E¹ leading to earth, and a wire C to
the battery C³, which may be of any of the ordinary constructions in use, a
and placed conveniently to the instrument B, B'.
Figures 8 and 9 are respectively a vertical and a horizontal section of
the coupling socket I and stems J, K, for connecting the portable
pieces L" of the main line wire L between the ends G' of the carriages G.
Figure 10 is a side and end view of the movable stem and socket
part J detached of the main coupling I secured to each end G¹ of the
carriage G.
a
-

page_text: Figure 11 is an edge and end view of the spring piece J, with its
holding catches J", J", for retaining the said movable stem and socket
piece J and the end stem K of the portable connecting pieces of wire L"
in their proper positions, as set and coupled by the attendants; Figure 12
being a side and end view of one of the end stems K of the said portable
coupling wires L" between the carriages G, H; and Figure 13 is a side
clevation of one of these portable coupling wires L", as fixed or inserted
into its two main couplings I, J, secured to the ends G' of two adjacent
carriages G, G.
"
Figure 14 is a side clevation of a train of carriages to a small scale,
showing the general arrangement of the line wire L, L, connecting the
alarm instruments B placed in the van H, H, at each end of the train,
and in the tender H", or the engine E', as also the wires C, E³, con-
necting these with the batteries C' and the axles F to earth, and also the
arrangement of "communicators A, in each compartment G" of the
carriages G connected by the wires L' to the main line wire L and E to
the axle F for earth; and Figure 15 is an end sectional elevation of a
carriage G, showing the coupling sockets I, J, attached to the end G₁ of
the carriage, and a communicator A attached to the interior end G* of
one compartment G" of a carriage G, instead of to the side wall of the
carriages G, as shown in Figure 14.
b
Referring to Figures 1 to 5 and to the improved construction and
action of each "communicator" or warning instrument and "tell tale"
combined A, A', for any passenger, while travelling in any compartment
or carriage of a railway train, to call the attention of the servants, or
the
guard and engine driver in the end vans H, and on the engine H',
main body part A' carrying the whole is formed of a turned disc or back-
board of wood A', which has a light deep cap or ring casc 6 hinged to it
at b (but it might also be slipped on as a cap without hinges and fixed
by other forms of locking catch than that shown), so as to fold down
with its inner edge 6 into the groove 6™, and thus close in all the
working parts free from harm or dust except the head or knob a,
which is made to reciprocate out through the hole 6* in the centre of the
outer glass and stationary face c, and within the central cylindrical
5 recess of the oscillating colored indicating or "tell-tale" disc d,
working close up to the three equally divided segmental apertures c¹,
each equal to one-sixth of the circle, so as respectively to show the

page_text: white d' and red d" segments of the disc d (through the apertures c¹ and
the glass ¹) when it is turned or oscillated one-sixth of the circle by its
hollow stend, d³, which works loose on the stationary hollow
stem e, e', screwed by its flange e' in the centre of the wood box A¹ and
within which the stem a of the knob a works, and is steadied and
prevented from turning by the square part a¹ and lateral pin a", which
works to and fro in the straight slot e" of the fixed hollow stem e, e¹,
and through an angled or spiral screw slot d³ in the outer loose turning
stem d, d³, of the disc d, which as well as the pressing spiral springf
below the inner stem a of the knob a is held in position by the
caps", respectively screwed on the outer and inner ends of the
fixed stem e, e¹, all so that when the knob a is pushed in by the fingers
or thumb of the passenger, as shown in the small perspective view,
Figure 14, against the power of the spring f, it would by the pin a" and
helical slot d³ turn the disc d one-sixth of a circle in the direction of the
red arrows 3, Figures 3 and 4, from the position shown in Figureș 1, 3,
and 4 to that shown in Figures 2 and 5, and show the red or danger
color through the spaces c¹ of the outer face c, as seen in Figure 2,
indicating also to the person pushing in the knob a that the guard is
warned. This turning of the disc d and its spindle d, d³ would carry
the catch segmental piece y fixed on the latter round to the position
shown.in.red.lines-in-Figure-4,-so-that-the-point-of-the-spring-catch
(with the switch i fixed to it for making and breaking contact with the
terminal stud of the carth wire E of the instrument), would, by the
power and action of the spiral spring j spring in past and catch the
end of the segmental piece g, and so prevent the disc d from turning
back or the knob a from rising after the guard has been warned, until
he came to the carriage from which the signal was given, and which he
would know by the instrument showing the red color! After attending
to the passenger and subject of the message, the guard would re-set the
instrument and disc d to its normal position by inserting the screw-
pointed key through the hole of the outer case b, and screwing it
into the outer end " of the spring catch, which when drawn back
against the power of the spring would free the segmental piece g, g',
and allow the colored "tell-tale" disc d to turn back in the direction of
the black arrows 4, all as indicated in Figures 2 and 4, by the outward
force of the spring fon the stem a¹, and the action of the pin a" in the
angular slot d³ of the stem d of the disc d, which would then bring the
knob a and white segmental spaces d' to their normal position, shown in

page_text: Figure 1, showing the whole face white, and the instrument ready for
action again when the guard has unscrewed and removed his key k¹.
Referring to the improved construction and arrangement of the parts
of the couplings I, J, K, for attaching the intermediate portable connect-
ing parts L" of the main line wire L between the carriages throughout
the train, in accordance with my Invention, and as shown more par-
ticularly in Figures 8 to 13, the permanent or main part of the coupling
proper is formed of the two parts I, J, the former fixed by the broad
flange and screw at I', preferably to the central wood part of the end G¹
of cach carriage and van G, HL, and engine and tender H³, H", throughout
the train sufficiently above the chain coupling not to interfere with or
be interfered by them, having the socket part I projecting out at right
angles to the ends G', or parallel with the sides and floor of the
carriages, with the stem J' (of the outer socket picce J for receiving the
connected end stems K of the portable coupling part L" of the main
line wire) attached to and working in the said socket I to the short
determined distance between the hollow curved notches o, o¹, into which
the round ended point J of the blade spring J" enters sufficiently to
hold the socket piece J, J', with great firmness, and prevent it shifting
from either position o, o', without a considerable longitudinal pushing or
pulling strain, besides being permanently fixed to it by the screw pin and
slot p, p. A second rounded pin J³ on the outer end of the said holding
spring J takes into the hollow notch o" in the flat side of an otherwise
cylindrical stem K fixed by a socket piece K' to each end of the coupling
wires L", which are formed of a few strands of fine copper wire well
insulated by a coating of gutta percha, and then covered with strips or
bands of tape or "Macintosh," and an outer strong coating of platted
strands of hemp or cordage, all well tarred to give perfect insulation,
and render them strong and weather-proof. The ends of the wires are
soldered and otherwise well attached to the metal stem K, which when
slipped into the socket J is held from shaking loose by the pin J³ and
spring J", and when completely coupled for, and before starting the
train the pin J* is inserted through both the slip socket J and stem K,
thus securing them, so that when a drawing strain comes on the coupling
wire L", as by a part of the train breaking away it draws out the slip
piece J, J', from the normal locked position shown in Figures 8, 9, and
13, until the pin J' enters the notch o, as indicated, drawn out to or
opposite that notch at Figures 10 and 11, which allows the spring to

page_text: press out the small cylindrical point or switch , both working within
the terminal " of the earth wire E" to come forward and make metallic
contact with the pin u, and so complete the circuit to both ends of the
train through and from the line wire L (soldered to the upper face of
the flange I¹) to the earth wire E" soldered to the inner end of its
terminal switch t, t','t", and which is fixed and insulated within the inner
hollow end I' of the main socket part I by the vulcanite flange and
point. Thus it will be seen that the strain of breaking any
coupling wire L" between the carriages by the separation of any portion
of the train will draw out the part J, J', of the coupling I, J, at the
separated ends of both parts of the train, and thus complete the circuit
through their wires L and E", as explained, in both parts of the train,
and set on the alarm bell of the instrument B carried in the vans or
engine, so as to warn the servants, who can see what has happened, and
then push in the slip pieces J, J', by hand, which would separate the
connection to both of the wires E, and still leave all ready for acting on
both parts of the train, or when the two parts of the train were again
coupled by a new coupling piece L" and the parts J of both coup-
lings I, J, closed (as shown in Figures 8, 9, and 13), the connection or
circuit would be complete throughout the main line wire L of the
train, all in its normal position-ready-for-action.-In-slipping_a_part_
of a train it is only necessary to remove one pin J* (secured by loose
chains to their couplings I), leaving the stem K still held by its spring
catch J, J³, so as to maintain the circuit complete for signalling
throughout the train until the actual moving off of the train, which
(without pulling out the piece J and putting on the connection to the
wire E" to earth) would separate the stem K from its socket J, and leave
the coupling piece L" hanging to the coupling of the carriage from
which the pin J* was not removed. A "communicator" A is screwed up
to a convenient side or end wall G" respectively of each compartment of
the passenger carriages G, as shown in Figures 14 and 15 by the two
metal screws 1, which pass through the metal plates " and ", and the
wood back A¹ into the screw nuts * and e* sunk or screwed into the
two sides or ends G" of the carriage G, and soldered to the wires L' and
E leading to the main line wire and the carth through one of the
axles F, all respectively as shown in Figures 4 and 5, and 14 and 1.5.
The connection from the main line wire L, L', through the instrument
is effected by the wire and guide plate " of the spring catch h, j, which
actuates the switch i to make and break contact with the carth terminal ¿

page_text: completing of the short circuit through any of the earth wires E of
the "communicators" A, or through the wires E of the couplings I
of the main line wire L by the loosening or breaking of the coupling
parts L" through accident or the separation of any portion of the train.
Each instrument B is also fitted with an insulated spring switch S,
connected by the wire S¹ to the turning screw L*, which is worked by
the commutator or switch stem and knobs passed through the crown of
the arched part of the box B, so that the pressing down of the knob
causes the circuit to be completed through the terminal screw E* and
wire E¹ to earth at either instrument or end of the train, thus enabling
the servants or guard and engine driver at opposite ends of the train to
convey to each other by a variety of beats of the bell signals for the
starting or stopping of trains, the indication of danger, or other purposes,
the needle N showing the direction of the current to the one side or the
other of the vertical line, which is its normal position when all is con-
nected right, with the currents acting through the whole in reverse
directions, or on what may be termed the equilibrium of opposite forces,
while the bell gives the signal or trembling alarm when the equilibrium
is destroyed and the current is flowing in either direction. In some
cases a "silent" z might be fitted on the signalling trembler bell
-instrument-B,-although-I-have-not-considered it necessary to do so, and
have therefore only indicated this in red lines in Figure 7, with the
wires and a from the terminals Q and C* brought to the switch
spring y, placed close to one side of the case B, through which the
spindle is passed with the reversing handle 2¹ outside.
Although I have only shown and described the knob a of the passenger
" communicator" A as flush with the glass b¹ and made to give the
signal by being pushed in it will be evident to practical engineers that
it might be made to project and give the signal or alarm by being pulled
out against the power of a spring, all otherwise, as or in an equivalent
manner to that herein shown, and described in reference to Figures 1
to 5; and that in like manner other details might be altered considerably
both in their form and construction without departing from the main or
essential features of my said Invention.
Having thus 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 would observe that what I consider novel and

page_text: original, and therefore claim as the Invention secured to me by the
herein-before in part recited Letters Patent is,-
First. The construction and arrangement of the parts of electric
apparatus for and mode of transmitting signals thereby on railway trains,
all substantially as herein described, and shown in the accompanying
Drawings.
Second. The working of signals on railway trains through the medium
of one conductor and the equilibrium of electric currents, substantially
as herein described, and shown in the accompanying Drawings.
"
"
Third. The construction and arrangement of the parts of the " com-
municator or guard warning instrument and indicating "tell tale
combined, for or on railway trains, substantially as hercin described, and
shown in the accompanying Drawings.
Fourth. The construction and arrangement of the parts of the con-
ducting couplings and their connections between the carriages of railway
trains, by which instantaneous warning is transmitted to the servants in
charge at each end of a train of the detachment whilst in motion of any
portion of the train, all substantially as hercin described, and shown in
the accompanying Drawings.
Fifth. The construction and arrangement of the parts of a trembler
alarm, communicating key, and galvanometer, and the application and
use of this instrument for signalling on railway trains, all substantially
in the new or improved manner herein described, and shown in the
accompanying Drawings.
In witness whereof, I, the said Edward Gilbert, have hercunto set
my hand and seal, this Ninth day of December, in the year of
our Lord One thousand eight hundred and seventy-two.
0
Witness,
W. R. M. THOMSON,
Patent Agent,
Glasgow.
EDWARD GILBERT. (L.S.)