Fog Signals for Railways.
Year: 1893

page_text: Date of Application, 9th Feb., 1893
Complete Specification Left, 20th.Oct., 1893-Accepted, 25th Nov., 1893
PROVISIONAL SPECIFICATION.
Electric Fog Signals for Railways.
HERBERT BROCKLEHURST of 24 Cheyne Court Mansions Chelsea Accountant
and HENRY CONSTIEN of 54 Queen Victoria Street London Tailor do hereby
declare the nature of this invention to be as follows:-
An apparatus for exploding by electricity a special form of cartridge whereby
a loud report is produced similar to the report made by the fog signals now in use
by railway companies. The essential features of this novel apparatus are as
follows, viz., attached to the existing wire or rod which is connected in the signal
box to the lever operating the signal upon the signal posts now in use is a wheel or
cylinder to which is fixed a ratchet movement in such manner that when the lever
is operated by the signalman in the usual way the connecting wire or rod moves
forward or backward for a certain distance and this movement being communicated
to the signal on the post causes the arm to drop or rise to signify "line clear" or
"danger
as the case may be. The movement of this wire or rod causes the
wheel or cylinder attached to it to move round a certain distance which is controlled
or regulated by the teeth of the ratchet movement attached to the wheel or
cylinder. But this movement is in one direction only notwithstanding the fact that
the connecting wire or rod moves both backwards and forwards, the ratchet
preventing the wheel or cylinder from moving in both directions. The circum-
ference or periphery of the wheel or cylinder is slotted out or grooved or toothed
or otherwise suitably formed so as to carry forward with each movement a chain
or band or strip or other suitable appliance of any material to which are attached a
number of special cartridges capable of being exploded by a current of electricity.
The chain or band or strip above mentioned may be paid out from another wheel
or cylinder running loose upon its axis and after being moved forward by the
ratchet wheel may be received upon a third wheel or some other suitable means
may be adopted for the storage and reception of the aforesaid chain or strip.
Attached to the axle of the ratchet wheel are two springs running upwards in such
manner that they touch the two ends of the cartridges as the cartridges are carried
forward by the movement of the chain or strip. This movement is so arranged
that at every pull or release of the lever in the signal box a fresh cartridge is
pulled forward by the ratchet wheel into the space between the two springs, and
thereby metallic contact is made between the two springs and the two ends of the
cartridge. The ends of the cartridge are made of metal and running from one
metal end to the other metal end inside the cartridge case is a fine platinum or other
wire which is in metallic contact with the metal ends. The cartridge case is filled
with gunpowder or some other suitable explosive or compound capable of being
exploded by the passage of an electric current through the aforesaid fine wire
whereby heat is generated. Attached to one of the springs above mentioned is a
wire carried into the interior of the signal box and in metallic connection with a
switch. From the switch another wire is carried to a suitable battery which may
be placed in any convenient position, preferably on the floor of the signal box.
From the battery is carried a wire to one of the rails at the spot at which the
This rail is
signal is desired to be heard by the explosion of the cartridge.
insulated from its two adjacent rails by the interposition of some suitable non-
conducting substance or simply by an air space between the ends of the rails,

page_text: suitable means being employed whereby the fish plates shall be prevented from
causing the rails to be in metallic connection with one another. From the other
spring abovementioned a wire is carried to the opposite parallel rail to the rail
which has been insulated in the manner described. This opposite parallel rail may
also be similarly insulated from its adjacent rails. It is evident now that the
electric circuit hereby created is broken at two points, viz. the switch in the signal
box and the space between the two opposite parallel rails. If now the switch be
moved to €6
on" whereby the continuity of the electric circuit at that point is no
longer broken, it is evident that the electric circuit remains broken only by the
space between the rails as described. If now the two opposite parallel rails be
metallically connected an electric current will flow from the battery through the
wire to one rail through the metallic connection to the opposite rail through the
wire to one spring through the cartridge to the other spring through the wire to
the switch and thence to-the-battery again. In its passage the current will explode
the cartridge in the manner substantially set out. The metallic connection
between the opposite parallel rails is caused by the wheels and axles of the engine
or carriage or truck or other vehicle passing over the said rails whereby the
current is allowed to flow from one rail to the other rail. But we do not confine
ourselves to any specific form of ratchet wheel, nor to the precise method described
of attaching wires to insulated rails. We propose to use one or more of several
methods whereby the train or vehicle passing over a particular spot may close an
electric circuit and cause a current to pass through the cartridges as already
described. We propose to use independently of or in conjunction with the method
aforesaid a thermo-electric pile or battery suitably placed upon or between or let
into or under the rail or rails aforesaid. This thermo-electric pile is composed of
any suitable different metals such as bismuth and antimony or selenium or copper
and iron or otherwise in such manner that the heat caused by the friction of the
wheels of the train or vehicle upon the rail or rails heats one of the junctions or
series of junctions of the thermo-pile whereby a current of electricity is generated
in the thermo-pile and flows according to known laws from the hot junction to the
cold junction or vice versa. This current is caused to flow along conducting wires
to a relay constructed upon the principle of relays in common use wherein the
weak current generated by the thermo-pile is caused to attract an armature which
by its movement is capable of closing a local circuit containing the signal-box
battery already described and the ratchet wheel and cartridge apparatus already
described. The passage of the train over the rails will by its friction through the
agency of the thermo-pile relay and battery cause the explosion of the cartridges in
the manner substantially set forth. In the alternative we propose to employ a
plunger or movable section of rail or a lever or a parallel secondary guide rail or a
separate conducting plate or rail in such form and manner that the engine or train
or vehicle passing over any particular spot may depress the plunger or cause the
movable section of rail or lever to close an electric circuit or by the wheel striking
against the guide rail a current may be caused to flow by the closing of an electric
circuit or a brush or other appliance may be carried upon the engine or other
vehicle and may come into metallic contact with the separate conducting plate or
rail aforesaid and close an electric circuit, all or any of which means we may
employ for the purpose of completing an electric circuit so as to cause a current to
pass through the cartridges as already described. The explosion of the cartridge
having taken place and the train having been brought to a standstill by its noise
we propose to use an ordinary electric bell attached to the signal post or elsewhere
in the vicinity of the spot where the train is at rest connected by conducting wires
to a push in the signal box or to suitable springs or contact pieces between which
the signal lever must pass when the lever is operated by the signal man to signify
"line clear." The ringing of the bell is the audible signal to the engine driver to
proceed. We do not confine ourselves to any specific form or detail in the method
of again starting the train after being stopped by the explosion of the cartridges.
We do not confine ourselves to the explosion of only one cartridge at one time but

page_text: we have described substantially the method we propose to employ for the
conveyance of an electric current to the apparatus described.
Dated this 9th day of February 1893.
HERBERT BROCKLEHURST,
24, Cheyne Court Mansions, Chelsea.
WANDY CONSTITN
COMPLETE SPECIFICATION.
Electric Fog Signals for Railways.
We, HERBERT BROCKLEHURST of 24 Cheyne Court Mansions, Chelsea,
London, Accountant and HENRY CONSTIEN of 54 Queen Victoria Street,
London, Tailor, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
This invention has reference to fog signalling on railways and it consists of an
apparatus by means of which a cartridge is automatically exploded by electricity
when the train reaches a given point; a loud report being thereby produced
similar to that made by the explosion of ordinary railway fog signals; the
invention includes a special form or construction of cartridge for use with the
apparatus.
For the purpose of the invention there are attached to or connected with any
convenient part of the usual mechanism by which an ordinary semaphore or other
like signal is worked by the signal lever, means or appliances whereby at every
movement of the signal in the one direction, but not in the other direction, a
cartridge is brought to a position in which it is subsequently exploded by an electric
circuit being automatically closed when the train reaches a given point. The electric
circuit comprises one or more fine platinum or other wires within the cartridge,
which wires on the passage of the current become heated and consequently explode
the explosive or detonating material that the cartridge contains. The cartridge
case is metallic at certain parts which are connected together by the above-named
wire or wires. One or more of these metallic parts, when the cartridge is in
position for being exploded, are connected with one pole of a battery, whilst one or
more of the other metallic parts are connected with the other pole except that
there is a break at one point of the circuit; this break is closed and the circuit
thereby completed by the train itself or by a device actuated by the train on
reaching the given point.
The appliances by means of which the cartridges are brought successively into
position may be worked from the ordinary signal wire or rod or from any other
convenient part of the usual mechanism by which the semaphore is operated; they
are preferably worked as hereinafter described from the counter-balanced lever of
the semaphore. The supply of cartridges may be carried in any suitable manner
and so that at every movement of the signal in the one direction a fresh cartridge
is brought into the exploding position. The cartridges may for example be carried
on a chain or band which is moved one stage at every movement of the signal in
the one direction; they are, however, preferably placed in a reservoir or hopper
from which they pass singly to grooves or recesses in a wheel or cylinder which by
a sort of ratchet movement turns to the extent of one stage or division at every
movement of the signal in the one direction and thereby brings a fresh cartridge
into position.
In combination with the electric fog signalling apparatus are means for giving
For this purpose
an audible signal to the driver notifying that he may proceed.
an electric bell or gong is placed near the place where the train has been stopped

page_text: by the signal; the circuit of this bell is completed by contacts made or operated
by the signal lever when this is moved to the "line clear" position; the bell is
consequently rung.
The apparatus comprises a switch under the control of the signalman, so that the
circuit in which the cartridge is placed may be broken when it is not required to
explode the cartridge.
The accompanying drawings represent an electric fog signalling apparatus
constructed and working in accordance with this invention in its preferred form.
Figure 1 is a side elevation of the apparatus.
Figure 2 is a plan showing also the electrical connections.
Figure 3 is a side elevation, Figure 4 a plan (with part of the cartridge reservoir
broken away) and Figure 5 a section on the line 5-5 of Figure 3 of the part of the
apparatus which effects the successive feed or supply of the cartridges.
.
Figure 6 is a section on the line 6-6 of Figure 2.
Figure 7 is a longitudinal section of one of the cartridges and illustrating the
preferred construction.
Figures 3 to 6 are on a larger scale than Figures 1 and 2, and Figure 7 is on a
still larger scale.
a represents the signal box, b the ordinary signal lever and c a chain or other
connector leading from the tail of the lever b round a pulley d, a pulley d', at the
signal post and any intermediate pulleys that may be necessary. e is the signal
post, is a lever having its fulcrum on the signal post at f'; the chain c is
connected to one end of the lever and the other end of the lever has a counter-
balance weight f2. The lever fis connected by a rod g. and cranked arm h to the
semaphore or signal arm i. The parts above enumerated are all of ordinary
construction. The lever fis attached near its weighted end by means of a link j
which is preferably a spring as shown, to one end of a lever k the opposite end
of which is pivoted at k¹. The lever k is therefore lifted when the lever f is lifted
and it descends when the lever f descends; it moves in a slotted guide ². Every
time the lever k rises it causes a wheel or cylinder to turn on its axis to an extent
equal to the distance between two of the grooves or recesses m m in the periphery
of the wheel ; when on the other hand the lever k descends it does not cause the
wheel to turn. The wheel receives its movement from the lever k as follows:-
The lever k is connected by a link n to the outer end of an arm p, the inner end of
which is loosely pivoted on the shaft q of a sort of ratchet wheel r. The ratchet
wheel r and the wheel m are both fixed to the shaft q. From the same shaft q
(which turns in bearings in the fixed frame g¹) an arm s loosely hangs and to the
lower end of this arm is attached a pawl or catch t for engaging with the teeth or
notches of the wheel r; the pawl t is also connected by a link or rod u to the arm p.
v is a stop catch to the wheel pivoted at a fixed point'v'. The drawings show the
above parts in their normal position, that is to say when the semaphore i is up or
at "danger" and the lever k is down. When the lever krises (to the position
indicated by the dotted lines k* Figure 1) simultaneously with the fall of the
semaphore to the "line clear" position, the pawl t through the action of the lever k,
link n, arm p, arms and link u is caused first to enter fully into that notch of the
ratchet wheel r which is immediately above it and then to travel upwards so as by
means of the said notch to cause the ratchet wheel to turn on its axis to an extent
equal to the distance between two of its notches. The wheel 7 being fixed on the
same shaft as the wheel turns to the same extent, that is to say an extent equal
to the distance between two of its grooves m m. In this turning movement the
stop catch is pushed by the wheel itself out of the notch in which it was engaged,
and then at the end of the movement drops into the next notch so as to hold the
wheel in its new position. On the descent of the lever k when the semaphore i is
raised to the " danger position, the pawl t through the action of the lever k,
link n, arms p and s and link u is first withdrawn from the notch in which
it is engaged and then travels downwards without moving the wheel r finally
stopping in the position seen in the drawings, that is opposite the notch below.
"
?"

page_text: Around
The length of the link u and its points of connection with the pawl t and
rm p are preferably such that the pawl at the end of this movement is
drawn somewhat into the notch of the wheel r as shown, so that its engagement
As the wheel is
with this notch in the next turning movement is ensured.
partially and intermittently turned as above explained its grooves m m are each
supplied in succession with a cartridge w from a hopper or reservoir and brought
to the exploding position which in the apparatus illustrated is the highest position,
in line with an open ended tube y. The cartridge case is made weakest at the ends
in order that the force of the explosion may chiefly be expended endwise, and with
this object the body of the case is preferably made of strong paper or other suit-
able material, and the ends are closed by wads w*w* as seen in Figure 7.
the cartridge case at the ends are metallic bands w' w' and around the middle is a
metallic band 02. The bands w¹ w¹ are connected to the band w² within the cartridge
by fine platinum or other wires z z. When the cartridge is in the exploding position
the two end bands w¹ w¹ are in contact with two metallic springs, and the middle
band w² is in contact with a metallic spring 2. One of the springs is connected
with a wire A (see Figure 2) which leads to a switch B and from the switch B
another wire C leads to one pole of a battery D; the wire A may be connected to
both of the springs z¹ but connection with one of them is sufficient because the two
springs are metallically connected through the metal of the apparatus.
spring which is in metallic connection with the springs by means of the
metal bands w wol, wires zz and metal band 102 is connected to an insulated bar E
from which a wire F leads to one of the metallic supports G of a short rail H
placed alongside but not in contact with one of the rails I of the railway; this
rail H has counterweights K K to return it to its normal position after having
been acted upon by a passing train as hereinafter described. From the rail 1 a
wire L leads to a spring contact M in the signal box, and when the signal lever b
is in the normal or danger position (as seen in the drawings) the tail of the
lever is in contact with the spring contact M. From the metallic frame of
the lever a wire N goes to the other pole of the battery D. It will thus be
seen that when the lever, is in the normal position and the switch B is closed
there is an electric circuit partly formed by the wires in the cartridge and
It will there-
complete except between the short rail H and the ordinary rail I.
fore be understood that when the first wheel of a train reaches the rail H,
between which and the rail I the wheel flange passes, metallic connection is made
by the train between the rails H and I, and the electric circuit is thus closed. The
current which then passes heats the wire and explodes the cartridge, thus
signalling to the driver that he is to stop.
The
In order that the driver may subsequently receive an audible signal that he may
proceed, an electric bell P is employed which is sounded when the semaphore i is
lowered. With this object a wire Q connected with the wire A is led to the
electric bell and another wire R from the bell to a spring contact S in the signal
box in such position that the tail of the signal lever when moved into the
"line clear" position comes in contact with the contact S; consequently the circuit
of the bell and the battery D is closed and the bell rings, the other circuit, that
is to say the cartridge circuit, being at the same time broken between the spring
contact M and the tail of the lever b. As the lever is moved over to the "line
clear" position the wheel makes a partial turn; the last exploded cartridge
falls down the shoot T and a fresh cartridge is brought into the exploding
O position.
Instead of arranging that the cartridge circuit shall be closed by the train
wheels acting upon a short rail such as H as hereinbefore described any other
suitable arrangement by which the train will close the circuit can be adopted. For
example the wire F instead of being led to a rail such as H may be led to the
5 other ordinary rail l' so that the electric circuit may be completed through the first
.pair of wheels and axle of the train; in this case the rails I and I'must be insulated
from the adjoining rails. Or a metallic brush or rubber may be attached to the

page_text: engine so as to make contact with a metallic projection on the rail I or elsewhere.
Or the train may be caused to depress a plunger which when depressed completes
the circuit. Or any other suitable known arrangement in ordinary electrical
railway signalling apparatus whereby the train on reaching a given point completes
an electric circuit may he adopted as will be well understood. Or the circuit
can be completed or closed by causing the train to bring into action a thermo-
-electric-pile or battery placed sufficiently near to the rails. This is illustrated
diagrammatically in Figure 8 in which represents the rail, U a thermo-electric
pile composed of any suitable different metals such as bismuth and antimony or
selenium. The heat caused by the friction of the wheels of the train heats one of
the junctions or series of junctions of the pile, and thereby causes a current of
electricity to flow from one junction to another. This current is caused to flow to a
relay V and to attract an armature W which when thus attracted closes at X the
circuit of a battery D which is the battery of the cartridge circuit. w indicates
the cartridge in position, 21 the two springs connected with one pole of the
battery and the other spring which is connected with the armature W. Instead
of a thermo-electric pile a very sensitive heat indicator such as those employed as
fire alarms and which complete an electric circuit when the heat reaches a prescribed
limit, may be employed.
It is obvious that various other arrangements than that shown in the drawings
can be employed for giving the cartridge carrying wheel a partial rotation at every
movement of the lever in the one direction so as to bring a fresh cartridge into
the exploding position, but the arrangement shown has been specially designed for
the purpose.
At ordinary times, that is to say when there is no fog the fog
signalling apparatus may be disconnected from the ordinary signalling apparatus ;
this can be effected by disconnecting the lever k from the lever for otherwise. As
this invention enables the fog signals to be worked by the ordinary signalmen when
doing their ordinary duty in the signal boxes, it is unnecessary to have special fog
signalmen for the dangerous work of laying fog signals upon the rails.
If, however, it be thought desirable to still work the fog-signals by special men,
the apparatus can readily be arranged to be worked by such men from safe positions
by means of levers or other appliances connected with the cartridge carrying wheel/
as will be readily understood.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. For fog-signalling on railways, an apparatus worked in connection with the
ordinary signal lever, or independently of such lever, so as to bring cartridges
successively into a position in which platinum or other wires within the cartridge,
which for the time being occupies the said position, form part of an electric
circuit having one break or opening, in combination with means for automatically
closing the said circuit by the train itself or by a device actuated by the train when
it reaches a given point, whereby on the train reaching this point and closing the
circuit the cartridge is exploded substantially as hereinbefore described.
2. The combination with apparatus arranged and working as stated in Claim 1,
of means substantially as herein before described, whereby an audible signal notifying
that he may proceed is given to the driver of a train who has stopped in obedience
to the fog signal.
3. In apparatus for electric fog signalling on railways, a wheel or cylinder having
recesses in its periphery to receive cartridges to be exploded, in combination with
means whereby the said wheel receives step by step rotation and a reservoir for
automatically and successively supplying the recesses with cartridges, substantially
as hereinbefore described.
4. An electric cartridge constructed with metallic parts and internal wires
substantially as hereinbefore described for use in fog signalling on railways as set
forth.

page_text: 5. The apparatus constructed, arranged and working substantially as herein-
before described with reference to the accompanying drawings for fog signalling
on railways.
Dated this 20th day of October 1893.
J. C. MEWBURN,
55 & 56, Chancery Lane, London, Chartered Patent Agent.