IMPROVEMENTS IN SIGNALLING PROAL
Year: 1883

page_text: LETTERS PATENT to James Enright of 34 Netherwood Road Kensington in
the County of Middlesex for an Invention of "IMPROVEMENTS IN SIGNALLING
PROVISIONAL SPECIFICATION left by the said James Enright at the Office
of the Commissioners of Patents on the 28th August 1883.
JAMES ENRIGHT of 34 Netherwood Road Kensington in the County of Middlesex
"IMPROVEMENTS IN SIGNALLING MAINLY APPLICABLE TO RAILWAYS AND IN
APPARATUS THEREFOR."
[1] For the first part of my invention I require a well insulated conductor laid
or fixed parallel and within a convenient distance of the ordinary rails on which
the trains travel It is continued to the station which the train is approaching
where are inserted in it first a galvanic battery and second one or more certain
pieces of registering apparatus to be described below. Thence it may be continued
back to the other station and connected with one or more registering apparatus
and then put to earth-At certain points the direct part of this insulated conductor
which I shall henceforward call the "double cable" approaches the rail and is
electrically connected to short insulated bare bars of galvanized iron or other
suitable material which I shall henceforward call electrodes The distances at
which the electrodes are fixed depend on the accuracy with which the position of
the train is to be determined-Close to these electrodes the direct part of the
double cable" may have inserted in circuit certain signalling apparatus to be
described below.
"
65
"
[2] I further require a second insulated conductor passing near the double cable
and which I shall henceforward call the "single cable "-This is also connected to
the electrodes similarly to the direct part of the double cable and at the
connectives or at a convenient distance from them has certain signalling apparatus
to be described below inserted in circuit with it-It is joined up with a galvanic
battery, key, or switch and put to earth so that a current may be sent through at
pleasure by a person at the station which the train approaches.

page_text: "
[3] I also require a means of making the train or similar moving body make and
break circuit which I shall call "
a key" I use two forms of "key" one used
when I want a momentary current to pass, a second when I want a current to exist
for a definite length of time.
In the first case I fix a spring in connection with earth so that the train as it
passes along acts (in a manner to be immediately explained) on it either laterally
or vertically and so brings it into connection directly or by the intervention of a
lever pulleys and chains & with one of the electrodes aforesaid or an extension of
the same or conversely the spring may be insulated and connected to the Electrode
when the passing train would put it to Earth.. The manner in which the passing
train effects the above is (a) by the flange of the wheels coming in contact and
pressing vertically or laterally on the parts above mentioned (b) or by having the
rail perforated vertically or laterally and the parts aforesaid of my "key" (springs
&) protruding through the perforations (0) or by affixing to one wheel of the
engine (or any other wheel of the train) a lateral extension of the tire on oither
side or a vertical extension of the flange (d) or by attaching to the engine (or other
part of the train) a piece of metal-after the manner of attaching guard-irons-to
which is fixed a small wheel which I shall call a "supplementary wheel." The
metal to which it is attached is bent so that it rolls outside or inside the rail at a
suitable height. The parts aforesaid of my "key" (springs &) are fixed in
positions such, that the wheels or the supplementary wheel or the lateral extension
of the tire or vertical extension of flange in (c) shall press on them as the train
moves along.
In the second case (when I require a current for a definite length of time) (c)
I fix to earth a spring bent at right angles with the free end notched. Its strength
as a spring may be improved by suitably fixing spiral springs pulling at right
angles. An extension of the Electrode with its end correspondingly notched is
brought near (not touching) so that when the bent spring or levers in connection
with it is actuated by the passing train as described above the notched end of the
bent spring and the notched end of electrode extension interlock thus making and
sustaining contact. At a point some distance on the line (a distance determined
by the time I wish the current to flow) one end of a bent lever is so fixed that the
supplementary wheel or vertical extension of flange or the lateral extension of the
tiro presses on it and so by the intervention of a chain working over and under
pulleys and which is so attached to the Spring bent at right angles mentioned
above that it is drawn away horizontally from the Electrode. The other spiral
spring then draws it away vertically and so unlocks them (f) Or I inay attach a
bent, lever the free end of which is fixed so as to be acted on by train as it moves
in any of the ways already described-by means of a wire rope or chain, working
if necessary by the aid of pulleys to a bolt kept normally supporting a metal bar
("contact bur") hinged to a Conductor put to Earth. When the train passes this
bolt is pulled back against tho power of the spring just mentioned, then the contact
bar is brought down by a weight or spring on an Electrode or extension of it.and
so makes contact. At some distance on (depending on the time I wish a current
to pass) another bent lever end is acted on by the inoving train and is connected
by a wire rope or chain working by the aid of pulleys to the "contact bar "so that
when the lever is worked the "contact bar" is lifted off the Electrode against the
power of the weight or spring and so breaks contact. The supporting bolt drawn
by its spring shoots under the contact bar" thus keeping the circuit open. I
require as many "keys" as Electrodes and the "make" of one key may be
simultaneous with the "break" of the next which is effected simply by fixing two
lever ends close together (g) or I may allow the current to flow normally and make
the signals by the "break clement" of any form of "key
21
3)
*
[4] I require an apparatus for indicating the position of the train at one or
nore places at both stations between which it is passing which I shall henceforward
call the "register I use different forms according to circumstances.
"
↑
(a) As the train passes over each "key" a bell rings at each station in several

page_text: places as required-At first the bell rings weakly but as the train nears the-station
and as the resistance in circuit decreases (current increases) it rings more strongly-
In order to magnify this difference in intensity of the bell sounds subsidiary
resistances are placed in circuit between the Electrodes-The bells at the station.
may be in circuit in series or in multiple arc-Any form of "key" may here
be used.
"
(b) I use a wheel turned by a coiled spring or by a suspended weight-It is
normally at rest kept so by a pin at the end of a lever and at right angles to its
plane The pin may not act directly but through the medium of other cogged
wheels and pinions in mechanical connection with it-The other end of the lever
just mentioned is of soft iron and so fixed that when a current is made to pass by.
the train passing over a "key an Electro magnet moves the lever against a
small spring which keeps it in normal position so as to relieve the wheel
momentarily The wheel has a series of notches or holes in its circumference into
which the pin fits and falls into in succession as the wheel turns being relieved.
continuously by the trains passing over the "keys"-An index is attached to the
wheel which points to the position of the train on the line-Every revolution of
the wheel corresponds to a train passing from one station to another-As the wheel
passes round it actuates a series of levers which strike a series of bells tuning forks
strings or other sounding bodies of different pitch so that the position of the moving
train is determined by the pitch of a sound, Or a cylinder may be attached to a
prolongation of the axis of the wheel-On this cylinder are fixed a series of pins
which as it revolves actuate directly or through the medium of levers sounding
bodies of any kind so as to make the most of pitch and timbre. The forms of
"key" described in (c), (d) (e) (f) in [3] are used for this form of "register," but
when (e) or (f) in [3] is used the continued current must be converted into a
momentary effect on the wheel above described. This may be done in three ways.
First two Electro magnets are placed in circuit in multiple are and when the current
passes one actuates the lever in connection with the register and the other breaks
this branch of the divided circuit.
Second One Electro magnet is placed in circuit which attracts a piece of soft
iron against the power of spring when the current passes-When the current is
cut off by the action of the "key" the soft iron flies away by force of spring and
makes contact which brings a special battery into play momentarily to work an
Electro magnet and withdraw the "pin" as before.
»
Third An Electro magnet is placed in circuit so as to act on pivoted piece of
soft iron and move it against the power of a spring-The free end of the soft iron
is notched and placed near the lever of the "register" carrying the "j pin
A small length of this end of the lever is hinged to the remaining part so that it
moves freely one way but not at all the opposite (valve like)-When the current
passes the Electro magnet brings the notched end of the pivoted soft iron into
contact with the moveable part of the lever-This yields and they interlock.
When the current ceases to flow the soft iron is drawn back by its attached spring
and actuates the lever thus with-drawing the "pin" as before.
J
(c) As the train moves over the "keys" when two lever ends are placed close
together (to make break of one section simultaneous with make of next) a current
is continually flowing but the resistance continually varying. Hence a measurement
of the Resistance in circuit determines position of train This may be done by:
keeping a constant Electro-motive force and Galvanometer at the points of
observation as Professors Ayrton and Perry do in their sectionally insulated Electric
Railway or by using a simple form of Wheatstone's Bridge where the ratio for
each measurement would be one of unity By subsidiary resistances inserted
between the Electrodes in series or multiple are the difference of resistance between
successive Electrodes may be made as high or as low as required-In the other
cases I use the Earth to complete Circuit but in this case it is better to use an
insulated conductor for the purpose as the Resistances of Earths is always
uncertain. By a similar use of subsidiary resistances the position of a Column of

page_text: Mercury in a Thermometer Barometer or of water &c in a cistern may be
determined at a great distance from them In the case of the Thermometer,
platinum wires must be inserted, by drilling holes, and then cementing or by
heating the glass and hermetically sealing them-transversely into the bore.
Between these wires Subsidiary Resistances are placed. As the Mercury rises it
cuts out these in succession so that the resistance measured as above gives the
position of the Mercury. The Subsidiary Resistances as before may be in series or
parallel circuit. If a very thin bad Conductor straight or coiled be fixed
longitudinally right through the bore the rise or fall of resistance in circuit also
reveals position of mercury There must either be a double (preferably) or a single
cable whose resistance is known laid from the instrument and connected with it to
the reading apparatus joined up in the usual manner with itself and a galvanic
battery. The roading apparatus is as that just described above.
[5] My "Keys" aforesaid in connection with the following apparatus to record
permanently the number of trains that pass and the times they pass and their speed
at different parts of the journey I require (a) an ordinary clock to wind or unwind
a paper ribbon on to or from a roller This ribbon passes over a stationary rod and
is tense. An electro-magnet is placed in circuit and when the current passes it acts
on a soft iron lever having a pencil attached to it and so placed that it marks the
paper ribbon as long as the current passes. Any form of "key" described above
may be used. The ribbon may be previously marked off in days hours &c to suit
the clock used (b) or a cylinder having a paper jacket drawn over it is made to
revolve on a continuation of the axle of the minute hand (or otherwise made to
revolve synchronously with it) of an ordinary clock and the pencil described in the
last paragraph is so fixed as to mark a line on it when the current is made to pass
by a train passing over the keys. At the end of every hour or other interval the
cylinder or the pencil is moved by the clock a small space in the direction of the
length of the cylinder so that each broken line across the paper jacket gives a
history of the trains that pass in an hour. This forward motion of the cylinder
may also be given to it by cutting a screw on the prolongation of the axis of the
cylinder and arranging it so that it may work in a companion screw To mark the
arrival of the train at the Station the pencil mark is slightly bent out of its
former course.
[6] I require certain signalling apparatus along the line in the neighbourhood of
the Electrodes (a) In the direct part of the "double Cable" in the Neighbourhood
of each Electrode I insert Electro Magnets to ring a gong also an induction coil in
connextion. with vacum tubes or bulbs or tubes or bulbs filled with certain gases to
give suitable colors as the spark passes, through them and a mirror placed behind
them to intensify the effect-This Apparatus works-and the signals-vis sounds
from a gong and the lights generated by the induction coil are produced by a
double event viz the trans passing over the "key" and the Signal Man at the
Station having made connection with the double Cable and a Galvanic battery.
The Battery that performs that is the same as that which works any of the
"registers" described in [4] The gong & is placed in the best position to be heard
by the driver of the Train and is fixed so that the sound is magnified by a sounding
board or resonator and a reflector to send the sound towards the Engine is fixed
behind it The coil & in same Circuit with it need not be at the same place but in
a position to attract the attention of the Driver with certainty
(b) Instead of the induction coil its accompanying tubes or bulbs a mirror may
be so set that when the current passes an electro Magnet brings it from behind a
dark board or screen and reflects a light of any suitable color placed on the Engine
for the purpose in such position as to ensure that the reflected light should striko
the eye of the Engine Driver
(c) At points in the single cable near the electrode Conductors are connected with
it and also with the Electroes. In these Conductors are inserted more powerful
signalling apparatus which may be actuated by the Signalman at the Station (in
the Signal box) sending (by the use of a switch or key) a current from the said

page_text: galvanci battery (or another) used to work the register and the signals described
in (b) of this paragraph-They consist of an Induction Coil with its disc a bell or
other suitable sounding body and which (Induction Coil) is connected with a
secondary condenser of any convenient and suitable form-The sparks or brush or
other form of discharge from the secondary condenser may be reflected from a
mirror so as to attract the attention with greater certainty-A sound reflector is
also fixed so as to direct the sound of the bell or other suitable sounding body to
the drivers ear. Here also I may use vacuum tubes or tubes filled with different
gases through which the discharge from the secondary condenser may pass and
produce lights of various colours as may be desired. More than one Condenser'
may be used and then they may be joined up in series or for quantity.
-
The two sets of signals described above may be used separately or in conjunction
according to circumstances they may be worked by 1 or 2 batteries

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said James Enright in the Patent Office on the 28th February 1884.
JAMES ENRIGHT of 34 Netherwood Road Kensington in the County of Middlesex
IMPROVEMENTS IN SIGNALLING MAINLY APPLICABLE TO RAILWAYS AND IN
APPARATUS THEREFOR"
This Invention has for its object improvements in signalling mainly applicablo
to-railways and in apparatus therefor.
One of the objects of my invention is to signal from a train to a station which
the train is approaching and there to indicate or record the progress of the train
along the line of railway. Also at the same time if need be to give a like
indication or record at a station in rear of a train or otherwise situate.
For these purposes I require an insulated telegraphic line and this may be
arranged in any convenient position noar the railway: a wire suspended on posts
in the ordinary manner is very suitable. At distances apart along the line and
close to the rails I arrange apparatus which in each case I connect by an insulated
wire with the telegraph line.
The apparatus which I call a contact post is so constructed that on the passage
of a train it establishes electrical connection with the bar of metal provided upon
the train. This bar of metal is carried by insulators but is electrically. connected
with the earth through a circuit wire and the wheels of the vehicles and the rails
of the railway line or in place of relying on contact through the wheels I apply a
spring to rub upon the rails.
At each contact post there is an insulator like an ordinary telegraph insulator
and it carries on its head a bow spring secured to the insulator by preference at
both ends and projecting up above it. A covered wire is led from the telegraphic
line and is connected with this bow. The bow is elastic and yields when the
insulated bar on the train comes against it and as the bar passes it rubs upon the
bow and establishes good electrical contact..
At the station to which the train is approaching I provide a galvanic battery
and also a receiving apparatus these are connected in series upon the insulated
line wire which afterwards is continued to a second station (if information at a
second station be required) and is then put to earth. This second station may be
in rear of the train or in any other position where it may be convenient to have it.
The battery may be carried upon the train.
The receiving instrument which I commonly employ either alone or together
with others is of the well known type in which each time that the circuit is
completed an index moves forward one step around a dial, in fact it is a "step by
step" receiver.
The dial of this instrument may be graduated to indicato distance from the
station in miles and parts of a mile or it may be graduated in any other convenient
manner.
A train passing along the line, and coming to a contact post completes the circuit
and causes the index to move one step forward. Similarly when it comes to thie
next post the train causes the index to make another step and so on. The index
thus moves step by step around the dial in accordance with the progress of the
train along the line of railway. The index thus will reach the zero point as the
train enters the station and in this position it will remain until another train enters
upon the section of the railway line at the further end.
I prefer that, the step by step instrument should also cause blows to be struck
upon sounding bodies of different pitch. In this case I employ an instrument
propelled by a clockwork and a suflicient, weight or spring. Each position of the

page_text: index has a sound of definite pitch to correspond to it. It follows that it is not
necessary for the signalman to watch the index.
When more than one line is under one signalman each line has an instrument
of definite timbre. For instance one line may have bells a second strings and
so on.
I can make use of a similar arrangement in order to communicate from the
station to the train when it is upon the line. When I desire to do this I
provide a second and more powerful battery on the train, I also provide a
key by which at pleasure the circuit of the insulated line wire can be closed at
the station.
Upon the train I also provide an induction coil the primary wire of which forms
part of the circuit of the battery which the train carries. This circuit is closed
by a relay also on the train and interposed between the insulated bar and the
earth connection. The relay operates whenever the train passes a contact post
provided the circuit has been closed at the station by means of the key.
The secondary circuit of the induction coil includes a vacuum tube or bulb of
the ordinary construction, viz, with platinum terminals sealed into the ends of a
glass enclosure containing a gas say hydrogen in a condition of great tenuity.
When the key at the station is depressed and the train reaches a contact post the
current passes through the primary wire of the induction coil. The ordinary make
and break appliance in connection with the induction coil renders the current
intermittent from which it results that a secondary discharge takes place through
the vacuum tube. These operations both by the sound occasioned and the light
emitted attract the attention of the driver of the train who accepts the
signal to stop, or the signal may have any other prearranged meaning assigned
to it.
Simultaneously with the vacuum tube discharge I employ indicators of other
sorts such as electric bells or galvanometers.
The driver or guard on the train can use the powerful battery referred to above
to initiate a communication to the signalınan at the station by means of a key on
the train. Any form of receiving instrument bells galvanometer and the like may
be used at the signal box for this purpose.
When my object is to indicate to a station the position of a train upon the line
of railway I may vary the arrangement first described by carrying the battery
upon the train itself.
The insulated line wire alongside of the railway is then connected to earth
through a receiving instrument at the station in advance as already described and
the current passes in this circuit and causes the movement of the index of the
receiver each time that the train passes one of the contact posts.
In this arrangement there may also be a second receiver in connection with the
same insulated wire at the station in rear of the train, and at this station also an
earth connection is provide?.
The current from the battery in the train when contact is made at one of the
contact posts, then divides when it reaches the telegraphic wire one portion of it
passing forward to the station in advance of the train and the other portion
passing backward to the station in rear of the train, and at both stations an
indication is given that is to say the index upon the dial of the receiver makes a
forward step. At the same time bells are sounded as already described.
.
In some cases together with the step by step receiver which indicates the progress
of the train by the movement of an index on the face of a dial I make use of a
recording instrument which gives a permanent record of the movements of the
train.
This recording instrument consists of a drum in connection with a clock and
driven by the clock so as to make say one complete revolution per hour. Paper is
wrapped around this drum and a pencil or marker is arranged to trace a line upon
the paper, the pencil remaining stationary whilst the drum rotates. The pencil
however does not remain always in contact with the surface of the paper. It is

page_text: bold in a holder which is capable of rocking to lift the point of the pencil from
the paper and this movement is given to it by the attraction of an electro
magnet.
When the circuit around this magnet is completed by the train passing one of
the contacts posts the magnet attracts its armature and this armature being
connected with the rocking frame the pencil is momentarily lifted from the paper
and a break is produced in the otherwise continuous line. Or this arrangement
may if preferred be reversed, the pencil being brought into contact with the
paper by the attraction of the electro magnet and at other times remaining out of
contact.
The pencil carrier is mounted upon a slide so that in addition to the rocking
movement it is capable of motion in a direction parallel to the axis of the drum.
In each rotation of the drum the slide is moved a short distance so that the line
traced by the pencil during the second rotation of the drum may not be coincident
with the line traced during the first revolution.
The movement of the slide parallel to the axis of the drum is communicated to
it by means of a rack which is suspended by a pair of links or otherwise and which
is moved or caused to swing laterally by an incline or cam upon the axis of the
drum.
A spring upon the slider engages with the teeth of the rack. Whilst the rack
receives a forward movement from the cam the slider partakes of this movement.
During each rotation of the drum the rack is moved by the cam a distance equal
to the space from one tooth to another and afterwards the cam permits of the return
of the rack either suddenly or gradually: But the rack in returning does not carry
back the slider with it for the tooth which previously had been driving the slider
forward leaves it and presently the point of the next tooth passes the end spring
deflecting it alightly without moving the slider. In the next revolution of the
drum this tooth becomes the driving tooth and when the rack moves forward
carries the pencil holder with it-Or a fine rack may be employed, and several
teeth may be taken at a time.
Thus it will be seen that as the drum continues to revolve the pencil will trace
a line upon it commencing at one end and passing round and round the drum until
it finally reaches the other end; the breaks in its continuity of the line correspond
to and record the times when contact boxes are passed and represent the progress
of the trains upon the line of railway. Thus a record is kept of the number of
trains that pass and the times when they pass.
In the electric circuit which is thus completed through the train at each contact
post I may if it should be necessary introduce upon the train or at the station or
stations electric bells to indicate the passage of each contact post and the due
completion of the electric circuit thereat.
I can also use in connection with the receiver or recorder already referred to ór
otherwise an instrument which enables me to ascertain by an absolute measure
the distance of the train from the station. This instrument is a Wheatstone
bridge of simple construction. In this bridge arrangement the current passing by
the insulated line is balanced in the well known manner against the current
through a known resistance. The resistance of the line wire will obviously
become less as the train approaches the station, the line wire being, thereby
shortened.
In order that this difference of resistance may be more marked, I employ a
telegraphic line having a high resistance, the resistance may if desired be increased
by inserting resistance coils between the contact posts. The resistances with
which the comparison is made are arranged in a resistance box and by well known
arrangements, the resistance in circuit can be varied by the movement of a slider.
To maintain the artificial resistanco in circuit proportional to the resistance of the
line circuit as the train approaches, the slider is, moved by hand along a course
and so long as the galvanometer in the cross connection of the bridge remains at
zero it shows that the resistances are accurately balanced.
--

page_text: The guide course may be taken to be a representation or model of the line of
railway and it may be graduated with .marks indicating mile posts and other
objects upon the actual line. The slider then may be taken to represent the train
passing along the line, and the position of this model train on the model line will
then always correspond to that of the actual train on the railway line so long as
the galvanometer by remaining at zero indicates that the current in one circuit is
balanced accurately by that in the other.
The last described method of signalling is applicable generally to ascertain at a
distance the position of any body upon any previously prepared track; thus it is
applicable to ascertain the position at which the mercury stands in the tube of a
distant barometer or thermometer. Conducting wires are for this purpose let into
the tube at distances the one from the other along the length of the tube. These
wires are connected in series the one to the other through high resistances, and the
wbole forms part of an electric circuit passing to the distant place.
The mercury rising in the tube connects one wire with another independently
of the external connection through the resistance coil consequently the rising of
the mercury progressively diminishes the resistance in the electric circuit. This
ristance I measure at the distant by the means already described, and from this
measurement I deduce the position of the mercury in the tube.
In instruments of this nature it is very convenient to construct the tube for
containing the mercury in vulcanite but other non-conducting material may be
employed.
Having thus described the nature of my said Invention and the manner of
performing the same I would have it understood that I claim :-
First. The combination of a receiving instrument or receiving instruments a
battery or electric source, a telegraphic line, and contact posts at distances apart on
the line, making earth connections during the passage of trains substantially as
herein described.
Second. The combination of a battery or electric source and keys a telegraphic
line contact posts at distances apart on the line making earth connections during
the passage of trains and vacuum tubes or bulbs or it may be other indicators
substantially as described.
Third. The combination of a Wheatstone Bridge arrangement, a telegraphic.
line, a battery or electric source and contact posts at distances apart on the line
and with artificial resistances between them such contact posts serving to make
earth connections and thereby complete the circuit during the passage of trains
substantially as described.
Fourth. The combination of a Wheatstone Bridge arrangement, a telegraphic
line, a battery or electric source and resistances which are successively short
circuited or placed in circuit by the movement of a mercury column or other body,
substantially as described.
Fifth. The receiving instrument in which is combined ordinary step mechanism
and bells or sounders operated thereby, substantially as described.
Sixth. The recording instrument with cylinder driven by a clock and with rack
propelment to traverse the pencil or marker substantially as described.
In witness whereof I the said Jaines Enright have hereunto set my hand and
seal this Twenty seventh day of February in the year of our Lord One thousand
eight-hundred and eighty four.