IMPROVEMENTS IN AND APPARATUS FOR SIGNALLING ON RAILWAYS
Year: 1874

page_text: LETTERS PATENT to William Thomas Whiteman, of No. 35, Maitland
Park Road, in the County of Middlesex, Gentleman, for the In-
vention of "IMPROVEMENTS IN AND APPARATUS FOR SIGNALLING ON
RAILWAYS."
Sealed the 17th March 1874, and dated the 22nd January 1874.
PROVISIONAL SPECIFICATION left by the said William Thomas
Whiteman at the Office of the Commissioners of Patents, with his
Petition, on the 22nd January 1874.
I, WILLIAM THOMAS WHITEMAN, of No. 35, Maitland Park Road, in
the County of Middlesex, Gentleman, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN AND APPARATUS FOR SIGNALLING ON
RAILWAYS," to be as follows:-
My Invention consists of improvements on the system of signalling
described in the Specification of Letters Patent granted to me in
O conjunction with Edward Umbers and Arthur George Fenn, and dated
4th January, 1873 (No. 56), and of apparatus to be used therein.

page_text: According to the said system a danger signal was exhibited to the
engine driver and guard of a train on the engine and in the break van
thereof respectively when it had approached within a prescribed distance
of a preceding train, by means of apparatus set on the permanent way,
which apparatus was actuated by apparatus carried by the said preceding
train, the starting signal being given to the driver of the following train
by sounding a gong on the aforesaid apparatus on the permanent way.
My improvements on the system described consist in giving the
starting signal to the driver by apparatus carried on the train instead of
from the aforesaid apparatus on the permanent way, and in automatically
altering a signal previously received on a train instead of leaving it to
be altered by the driver as provided for in the Specification herein-before
referred to, and my Invention of apparatus to be used in carrying out
the aforesaid improved system consists of the automatic electrical
apparatus herein-after described, part of which apparatus I substitute
for the mechanical apparatus described in the Specification of the said
Patent.
According to my Invention I furnish each train with apparatus
herein-after termed "receiving apparatus" for receiving from apparatus
fixed on the permanent way and termed " delivering apparatus” and
herein-after described. A current of electricity from a local battery
which actuates " exhibiting apparatus" carried on the train, by means
of which exhibiting apparatus the signals are exhibited on the said train
to the driver or guard, or both. The aforesaid delivering apparatus is
put in electrical connection with the aforesaid battery by the action of
other apparatus herein-after termed "transmitting apparatus" which is
also fixed on the permanent way, which transmitting apparatus is acted
on and thus caused to transmit the current of electricity cither by
apparatus herein-after termed the "actuating apparatus" carried by the
said train, or by apparatus moved by the wheels or other parts of a
train by which the aforesaid electrical circuits are completed.
The receiving apparatus consists of an insulated wire brush or brushes,
or spring or springs, affixed to some suitable part of the train, which
brush or brushes, or spring or springs, is or are in electrical connection
with an electro-magnet or electro-magnets, or other suitable appliances,
forming part of of the exhibiting apparatus.
The exhibiting apparatus consists of any suitable electrical contrivance
or contrivances for giving a visible or an audible signal or.both to the

page_text: engine driver, and (if considered necessary) an apparatus for recording
the signals so received; for instance, a semaphore and bell, and a
Morse telegraphic printing apparatus, respectively. The said exhibiting
apparatus is connected to the insulated brush or brushes, or spring or
springs of the receiving apparatus, and is so arranged as to give one or
more distinct signals on the engine, as for instance "danger" and "line
clear," according to whether one or other of the said insulated brushes
or springs is or are in electrical connection with the delivering apparatus
herein-after described, or according to the direction in which the
electrical current passes.
The delivering apparatus consists of one or more insulated strips of
metal or other equivalent electrical conductor or conductors mounted at
a suitable spot in the path of the receiving apparatus and electrically
connected to the local battery and an earth plate or to a relay, and
thence to the battery and an earth plate, the said relay being arranged
so as to complete the circuit between the battery and one or other of
the said strips, or to reverse the direction of the current if only one strip
be used.
The transmitting apparatus consists of one or more insulated strips of
metal or other equivalent conductor or conductors mounted at a suitable
spot in the path of the actuating apparatus (herein-after described).
When the strips are used in pairs one strip of each pair is connected to
the aforesaid battery, and the other strip of each pair either to a local
relay, or to the relay of a distant signal station, or both. When only
one strip is used the electrical circuit is completed from the local battery
or a battery on the train through the said strip, and through the wheels
of the train and the rails to the herein-before last mentioned relay or
relays.
The transmitting apparatus and the delivering apparatus may be set
at any suitable distance apart.
The actuating apparatus (like the receiving apparatus aforesaid)
consists simply of an insulated wire brush or brushes, or spring or
springs affixed to the engine or train, which brush or brushes, or spring

page_text: The action of my apparatus is as follows:-When an engine or train
passes one of the transmitting apparatuses the brush or brushes, or
spring or springs constituting the actuating apparatus rubbing against
the metal strip or strips of the said transmitting apparatus makes or
make electrical connection between the said strips, or between a local
battery or a battery on the said engine or train and the said strip. A
current of electricity is thus caused to pass from one or other of the
before-mentioned batteries to the relay of a distant delivering apparatus
which completes the circuit between the local battery at that signal
station and the metal strip or set of metal strips forming part of such
delivering apparatus, which strip or strips delivers or deliver the current
to the receiving and exhibiting apparatuses and thereby gives or give the
danger" signal. The current then passes to the relay of another
distant delivering apparatus, by means of which relay the circuit is
completed between one of the aforesaid batteries and the insulated strip
or strips which delivers or deliver the "line clear" signal as before
described. Or the direction of the electric current may be reversed by
means of the relays to give the signal or signals.
66
The actuating apparatus acts in a similar manner on each transmitting
apparatus as the train passes it, and a current or currents of electricity is
or are transmitted to the relay or relays of a distant delivering apparatus
or apparatuses, by means of which relays the electrical circuits of the
local battery or batteries or a battery on the train are so completed that
the brush or brushes of the receiving apparatus of another train rubbing
against the insulated strip or strips of the said delivering apparatus or
apparatuses shall receive a current or currents of electricity which shall
show on the exhibiting apparatus of the said train the "danger" or the
"line clear" signal.
When the driver has received the danger signal in passing a delivering
apparatus he slackens speed, and if in passing the nearest of the
insulated strips forming part of the next delivering apparatus the danger
signal is repeated he stops the train with its receiving apparatus in
contact with the next portion of the said delivering apparatus, and
remains there until the "line clear" signal is given by the current
being caused to pass through the other strip or strips, or by the direction
of the current being reversed by the actuating apparatus carried by the
train which blocks the line. But if the danger signal be not repeated
and the signal "line clear" be given he goes on.

page_text: When a train is being backed on the line the signals are not altered
because the actuating apparatus acts on the several insulated strips of
the transmitting apparatus or apparatuses in the reverse order whereby
the circuits necessary to complete the circuits of the local batteries,
which actuate the exhibiting apparatus are not completed. In some
cases I prefer to attain this end by making the actuating apparatus
moveable, and withdrawing it either automatically or otherwise when
the train is being backed so that the said actuating apparatus may not
rub against the transmitting apparatus.
Instead of actuating apparatus of the kind described tappets or
springs or levers arranged on the permanent way and moved or pressed
by the wheels of the engine may be used to complete the various
electrical circuits.
Where desirable or necessary (as at termini) instead of completing
the electrical circuits to the delivering apparatus by the action of the
transmitting apparatus worked automatically by a passing train as
described, they may be completed by means of a contact maker worked
by a signalman at any suitable place, and in the case of junctions the
said contact maker may be worked by or in connection with the point
levers so that a signal shall be given according to the position of the
points.
The apparatus herein-before described may if desired be combined with
apparatus for indicating or for recording the signals at a signal station.
The essence of my Invention consists in giving signals automatically
on or to trains through apparatus set on the permanent way by means
of electric currents, the electrical circuits being completed by means
of intermediate electrical apparatus, the circuits of which are completed
by electric currents transmitted either automatically by means of
apparatus carried by or worked by other trains, or by apparatus worked
from a signal station through other intermediate apparatus set on the
nermanent way

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Thomas Whiteman in the Great Seal
Patent Office on the 22nd July 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
THOMAS WHITEMAN, of No. 35, Maitland Park Road, in the County
of Middlesex, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-second day of January, in the year of
our Lord One thousand eight hundred and seventy-four, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said William Thomas Whiteman, Her
special license that I, the said William Thomas Whiteman, my exe-
cutors, administrators, and assigns, or such others as I, the said William
Thomas Whiteman, 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 AND APPARATUS FOR SIGNALLING ON
RAILWAYS," upon the condition (amongst others) that I, the said William
Thomas Whiteman, 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 William Thomas Whiteman, do
hereby declare the nature of the said Invention, and in what manner
the same is to be performed, to be particularly described and ascertained
in and by the following statement thereof, that is to say:-
My Invention consists in giving signals automatically on or to
trains through apparatus set on the permanent way by means of clectric
currents, the clectrical circuits being completed by means of intermediate
electrical apparatus the circuits of which are completed by electric
currents transmitted either automatically by means of apparatus carried

page_text: by or worked by other trains through other intermediate apparatus set
on the permanent way.
According to my Invention I furnish each train with apparatus
herein-after termed "receiving apparatus" for receiving from apparatus
fixed on the permanent way, and termed "delivering apparatus," a
exhibiting
current of electricity from a local battery which actuates “
apparatus" carried on the train, by means of which exhibiting apparatus
the signals are exhibited on the said train to the driver or guard, or
both. The aforesaid delivering apparatus is put in electrical connection
with the aforesaid battery by the action of other apparatus herein-after
termed "transmitting apparatus" which is also fixed on the permanent
way, which transmitting apparatus is acted on and thus caused to
transmit the current of electricity by apparatus herein-after termed the
' actuating apparatus" carried by the said train by which the aforesaid
electrical circuits are completed.
"
The receiving apparatus consists of an insulated wire brush or brushes,
or spring or springs affixed to some suitable part of the train, which
brush or brushes or spring or springs is or are in electrical connection
with an electro-magnet or electro-magnets or a relay or other suitable
appliances forming part of the exhibiting apparatus.
The exhibiting apparatus consists of any suitable electrical contrivance
or contrivances for giving a visible or an audible signal or both to the
engine driver, and (if considered necessary) an apparatus for recording
the signals so received, for instance, a semaphore and bell and a
Morse telegraphic printing apparatus respectively. The said exhibiting
apparatus is connected to the insulated brush or brushes or spring or
springs of the receiving apparatus and is so arranged as to give one or
more distinct signals on the engine, as for instance, "danger" and
"line clear," according to the direction in which the clectrical current
passes.
Figure 1 of the accompanying Drawings represents an apparatus
suitable for this purpose.
A, A¹, is a small permanent magnet made of hard iron or steel
mounted on a centre A³ so as to be capable of oscillating in a vertical
plane; A is a light iron bar affixed to A, A¹; A5 is a small bar to serve
as a counterbalance to A*; a, a¹, are two small dises of card or metal
affixed to the upper extremities of A, A', and A+, respectively; B is an

page_text: electro-magnet, the coils of which B¹, B³, are connected at each end
through intermediate conductors to the brushes of the receiving
apparatus when two brushes are used, or when only one brush is used
one end of the said coil is connected through the insulated wire to the
said brush which is itself insulated, and the other end of the said coil is
connected to the metallic body of the engine and so through the engine
wheels to the rails; C is an electro-magnet which is inserted in the
circuit of the above-mentioned magnet B which magnet C when the
current passes attracts the armature c¹ and thereby causes the hammer c²
to strike the bell D. This apparatus is enclosed in a case (not illustrated)
in which is an aperture behind which one or other of the two discs
indicating "lino clear" or "danger" is brought and held by the
magnet B. The said exhibiting apparatus may if preferred bo worked
by a battery on the engine, the circuit of the said battery being
completed by the action of a relay actuated by the current passing
through the receiving apparatus, such battery being either in addition to
or in substitution for the battery on the permanent way.
The delivering apparatus consists of one or more insulated strips of
metal or other equivalent clectrical conductor or conductors (having
clean surfaces of such a kind as to be but little liable to oxidation)
mounted at a suitable spot in the path of the receiving apparatus, for
instance at the side of the line of rails or on the sleepers between the
rails, and electrically connected through a relay to a local battery, the
said relay being arranged so as to reverse the connections and so reverse
the direction of the current.
Figure 2 is an elevation; Figure 3 is an end clevation partly in
section taken on the line 1, 2, Figure 2; and Figure 4 is a plan of the
"double strip" delivering apparatus showing a method of mounting and
insulating the said strips when they are mounted at the side of the line
of rails; a, a, are the strips fastened to planks b, b, which are bolted to
posts c, c, mounted on the sleepers d, d. The planks b, b, are insulated
by washers e, e, and tubes f, f, which are made of cbonite or other suitable
insulating material. The said strips must be of a length adapted to the
speed of the fastest trains on the line. For ordinary speeds a length of
15 fect is sufficient, and in some cases even less.
The transmitting apparatus consists of one or more insulated strips of
metal or other equivalent conductor or conductors having clean surfaces,
mounted at a suitable spot in the path of the actuating apparatus hercin-

page_text: after described. The strip or strips of the transmitting apparatus may
be mounted as described and illustrated with reference to the delivering
apparatus, but it or they must be mounted in a different vertical or
horizontal plane from the strip or strips of the delivering apparatus, so
that the brush or brushes, or spring or springs of the receiving apparatus
before described shall not come in contact with the transmitting appa-
ratus, and the brush or brushes, or spring or springs of the actuating
apparatus before described shall come in contact with the transmitting
apparatus, but not with the delivering apparatus. The said transmitting
apparatus and the delivering apparatus may be set at any suitable
distance apart.
Figure 5 is a diagram showing the general arrangement of the single
strip delivering and transmitting apparatuses and their connections with
the relays and batteries, the various parts and connections representing
three different signal stations (marked respectively stations 1, 2, and 3,)
at convenient distances apart. In this Figure and in Figure 6 the relays
are for convenience in tracing the circuits drawn of about the full size,
and the other portions of the diagram on much smaller scales.
The letters C and Z in each of the diagrams, Figures 5 and 6, indicate
the copper and zinc poles of the batteries, and the arrows show the
direction in which the currents pass, i.c., from zinc to copper.
The relays illustrated in the diagrams are polarized relays which I use
by preference, but it is obvious that other double circuit relays could bo
used instead; A¹, A², A³, are the strips of the delivering apparatus.
These strips are connected by the wires a¹, a², a³, to the screws b¹, 6ª, b³,
6ª, and 6º, 6º, of the polarized "delivering" relays B³, B³, B³. The said
relays are connected to the batteries B*, B³, B', as follows:-The wires
from the zinc poles are connected respectively to the tongues c¹, c², c³,
which tongues are permanent magnets. The wires from the copper
poles are connected to the springs d', d³, d³, d', and d³, d. The screws
e¹, e, e, e, and e, e, are connected by the wires f¹, f,ƒ³, to the rails
G¹, G³, G³.
A, A, A, are strips of metal (which I call distance delivering
apparatus) connected by wires a, a, a, to the strips of the delivering
apparatus A', A', A', for the purpose herein-after explained. The
magnets B', B2, B3, of the relays B³, B³, B³, are each wound with two
coils of wire, so as to be acted on by two different currents travelling in
independent circuits.

page_text: H³‚ H³, H³‚ H³‚ H³, H, are the strips of the respective transmitting
apparatuses. The strip He is connected to the copper pole of the
battery by the wire, and the zinc pole of the said battery is con-
nected by the wire to the tongue of the "transmitting" relay J³ the
screw je of which is connected by the wire 10 to one end of one of the
coils B³× of the electro-magnet B3 of the "delivering" relay B³, the
other end of which coil is connected by the wire k¹ (which is an ordinary
telegraph wire insulated by one of the usual methods) to one end of one
of the coils J** of the magnet J of the "transmitting" relay J³, the
other end of which coil is connected to a telegraph wire ², which passes
to one end of one of the coils B¹× of the magnet of the polarized
"delivering" relay B', the other end of which coil is connected by the
wire ³ to the carth plate % from which the current passes (when the
circuit is closed as herein-after described) to the earth plate k³, thence to
the rails and through the engine wheels and engine, and the actuating
apparatus to the strip H°, and thence by the wire to the copper polo
of the battery h°. The strips H³, H', are each connected in like manner
with other relays and earth plates. The strip H³ of the transmitting
apparatus is connected to the copper pole of the battery 15 by the wire
h', the zinc pole being connected by the wire 8 to one end of one of the
coils J³ of the magnet J³, the other end of which coil is connected by
the wire ho to the rail G³. The strips H¹ and H³ are in like manner
connected respectively to the batteries h¹, hs, and to one end of one of
the coils J, J2*, of the magnets J¹ and J' respectively, and thence to
the rails G¹, G³.
The "actuating apparatus" (like the receiving apparatus aforesaid)
consists of a wire brush or brushes or a spring or springs affixed to the
engine or train, which brush or brushes or spring or springs is or are so
arranged and electrically connected to the wheels of the engine as to
complete the electrical circuits of the batteries h¹, h², h³, h³, h³, he, from
the transmitting apparatuses H, H², H³, H*, Hº, H', through the wheels
of the trains to the rails, or in some cases if preferred it may be an
insulated brush connected to one pole of a battery carried by the train,
the other pole of the said battery being connected to earth through the
wheels. This said battery would then do the work which in the Diagram
is shewn to be done by the batterics h¹, h², h³, h, h³, hº.
The action of my apparatus is as follows:-When an engine or train
passes the transmitting apparatus H¹ the brush or brushes or spring or

page_text: springs constituting the actuating apparatus rubbing against the strip H'
of the transmitting apparatus makes or make electrical connection
between the said strip and the rail, thereby completing the circuit indi-
cated in blue lines through one coil of the electro-magnet J', by means
of which the tongue 1 of the relay is attracted to the right-hand screw j*,
which makes contact in such a way that when the transmitting apparatus
of the same train travelling on from right to left comes in contact with
the second transmitting apparatus H it completes another circuit from
the battery, the whole of which circuit is not shown, but the whole of
the corresponding circuit at another signal station is shown in connection
with the transmitting apparatus H. On the circuit from the battery h²
being completed, the current passing around one coil B¹× of the clectro-
magnet B', the tongue c¹ of the relay B' is attracted to the right hand,
and if the relay is a polarized one the said tongue is held there by
magnetic attraction until a current is passed round the magnet in the
reverse direction, or if it is merely a tumbler relay the said tongue is
held there by its own weight until the reverse current passes. Tho
tongue c¹ presses the spring d² against the screw e¹ by means of the ivory
stud c', and so connects the copper pole of the battery B' to the screw c¹,
and thence to the rails, and the said tongue c¹ pressing against the
screw b¹ connects the zinc pole of the battery through the said screw b¹
to the delivering apparatus A'. The electrical circuit of the battery B* is
now so completed that the brush of the receiving apparatus of a following
train rubbing against the strip of the delivering apparatus would receive
a current of electricity which passing through the coil of the magnet B
of the exhibiting apparatus (Figure 1) would cause the danger signal
to be exhibited, and this signal would be given to any following train
until the position of the tongue c¹ of the relay B' had been reversed,
as herein-after described.
When the first-mentioned train passes the transmitting apparatus
H³, H', at signal station No. 2, circuits similar to those above described
with reference to the apparatus H', H², at signal station No. 1 will be
completed. When the same train passes the transmitting apparatus
H', H, at the signal station No. 3 similar circuits are again completed.
The second circuit, namely, that from the battery /, which was only
partly described and illustrated with reference to the transmitting
apparatuses H and H' may now be fully described as follows:-The
tongue having been attracted to the screw j by the action of the

page_text: actuating apparatus passing the transmitting apparatus H³ the contacts
are so made that the circuit of the battery he will be completed when
the actuating apparatus of the train passes the transmitting apparatus H®.
The course of this current will be as follows:-From the zinc of the
battery it will pass through the wire to the tongue of the relay J³,
and through this tongue to the screw *, thence through the wire j¹ to
one end of one of the coils B** of the electro-magnet B³ of the
delivering apparatus at the same station, the current passing round this
magnet will attract the tongue c³ of the polarized relay B³ of the
delivering apparatus to the right, and so complete the necessary contacts
with the battery Be that as before described with reference to battery B*
a following train shall receive an electric current in such a direction as
to give the danger signal on the exhibiting apparatus. From the
magnet B³ the current passes by the telegraph wire k¹ to one end of one
of the coils J of the magnet J at the last preceding signal station,
namely, No. 2. This current passes round the magnet in the direction
indicated by the arrows, removing the tongue of the relay from
contact with the screw j³ and bringing it into contact with the screw j.
The current then passes along the telegraph wire ² to the next pre-
ceding signal station, namely, No. 1, to one end of one of the coils B¹×
of the electro-magnet B¹. The current will pass around this magnet (as
indicated by the arrows) in the reverse direction to that in which it
passed around the magnet B³ at the before-mentioned signal station,
No. 3, and will reverse the polarity of the magnet so that it will attract
the tongue c¹ of the relay from the right hand to the left and reverse the
connections of the battery B*, so that the actuating apparatus of any
following train passing the delivering apparatus A¹ may receive the
current in the reverse direction and so give the signal "line clear" by
the exhibiting apparatus of the engine. From the coil B¹ of the
magnet B¹ the current will pass through the wire ³ to an earth plate k*,
and thence to an earth plate ³, thence to the rails and through the
wheels of the engine or train to the actuating apparatus, and thence to
the transmitting apparatus H, and back to the copper pole of the
battery 7. This current will therefore in its course set the polarized
relay of the delivering apparatus at station 3 to "danger," alter the
position of the tongue of the transmitting relay at station 2, and set
the polarized relay of the delivering apparatus at station 1 to "line
clear"

page_text: In the case of junctions it is sometimes necessary to put the signals,
which are otherwise wholly automatic, under the control of a signal
man. This can be effected by leading the conductiug wires attached to
the delivering apparatus into the signal cabin and using a commutator
of any ordinary known form to complete or reverse the circuits. I 5
specify this as a matter of detail which may be useful, but do no claim
it as part of my Invention.
When desirable or necessary (as at termini) instead of completing the
electrical circuits of the delivering apparatus by the action of the trans-
mitting apparatus worked automatically by a passing train as described 1
they may be completed by means of a contact maker worked by a
signalman at any suitable place, and in the case of junctions the said
contact maker may be worked by or in connection with the point levers,
so that a signal shall be given according to the position of the points.
The apparatus herein-before described may if desired be combined 1
with apparatus for indicating or for recording the signals at a signal
station and with electrical point-locking apparatus.
In some cases it may be necessary to enable a train to pass the signal
stations without acting on the signalling apparatus. This may be pro-
vided for by so mounting the brushes of the actuating apparatus that ?
their position relatively to the transmitting apparatus may be mechani-
cally altered.
One arrangement by which I effect this is as follows:-I mount the
brushes of the actuating apparatus, one of which brushes projects from
each side of the engine or tender, upon a rod or shaft, which rod is
herein after termed the brush rod, and is capable of motion in a
horizontal plane in a line parallel to the axles of the engine wheels.
Affixed to the reversing lever is one end of a rod, to the free end of
which a stud is affixed, which stud rests in a groove of a suitable form
(such for instance as that shewn in the diagram, Figure 7), which
groove would be formed in a plate affixed to the brush rod. By this
arrangement when the reversing lever is moved forward or backward the
brush on one side is caused to project and that on the other side is with-
drawn; or the same result may be attained by causing the reversing
lever to electrically disconnect one of the brushes and to electrically
connect the other to the proper circuits. I prefer the latter mode,

page_text: 7. They can if desired be given at the same moment to both driver
and guard.
8. They will greatly conduce to the general security of railway
travelling.
9. Owing to the absence of human agency, and to the apparatus not
being subject to the wear and tear of mechanical apparatus, they will be
much cheaper than the present signals as well as more efficient.
Having now described the nature of my Invention, and the manner
in which the same is to be performed, I wish it to be distinctly under-
stood that I do not claim, per sc, the arrangements of metal strips used
as transmitting and delivery apparatus, as I am aware that other
equivalent contrivances have been previously used for the purpose of
transmitting electric currents. Neither do I claim the use of the metal
brushes or springs which I use as actuating and receiving apparatus, as
I am aware that similar contrivances have been previously used for
railway signalling. Neither do I claim the use of a simple relay, as I
am aware that relays have been previously used for railway signalling
purposes, although not polarized relays. Neither do I claim the use of
a recording apparatus in railway signalling; but what I do claim
is,―
Firstly. The improved mode herein-before described and illustrated in
the accompanying Drawings of signalling upon railways, that is to say,
automatic signalling wholly by means of electricity from a train to
another train in such a manner that one train shall warn the driver or

page_text: guard of the other train by causing an automatic visible signal, such as
the moving of a coloured glass, or disc, or semaphore, or an automatic
audible signal, such as the sounding of a bell, or both signals, to be given
on the engine or in the break van of the train to which the signal is to
be given when such train has approached within a prescribed distance
of the signalling train, and also in informing the said driver or guard
that the line is clear by giving a different automatic signal on the engine
or in the break van of the said train to be signalled.
Secondly. The combination and arrangement of apparatus for
automatic electrical train signalling herein-before described and illus-
trated in the accompanying Drawings.
In witness whereof, I, the said William Thomas Whiteman, have
hereunto set my hand and seal, this Twenty-first day of July, in
of our Lord One thousand eight hundred and seventy-
the year
four.
Witness,
°
H. H. MURDOCH,
7, Staple Inn,
London.
W. T. WHITEMAN. (L.S.)