Improved Means for Electrically Operating Signals and Crossing Gates on Railways.
Year: 1889

page_text: COMPLETE SPECIFICATION.
Improved Means for Electrically Operating Signals and Crossing
Gates on Railways.
1, JAMES HENDERSON HUNTER, of Vanderbilt Building, in the City of New York,
United States of America, Engineer, 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 relates to that class of danger-alarms used in electric block-signal
systems on railways, wherein a signal is sounded or displayed in the cab of, or on, the
locomotive whenever there is special danger ahead; for example, when there is a train
in the same block, a switch misplaced, or a drawbridge open. In these danger-alarm
systems there have been employed suitable electrical conductors (connecting the
magnets of circuit-breakers or relays) at the points which divide the road up into
blocks or sections, and also at other points where needed; as, for example, near
switches and draws. The conductors act in conjunction with an electric current
generator on the locomotive, such as a dynamo driven by a special engine or motor;
the generator being in a normally-closed circuit with sonie part of a signal mechanism
in the cab. When the circuit is broken, the danger-alarm is sounded. At the moment
the locomotive reaches a point on the road where a relay is situated, as at the entrance
to a block, a track-circuit or partial circuit, controlled by the relay, is thrown into
and made to form a part of the circuit on the locomotive. Now if the relay is set to
safety," the circuit will be closed by it, and no danger signal will be received by the
engineer; but, if the relay has been set to "danger," the circuit will be open, and,
at the moment the locomotive passes the receiving point, a signal will be given. When
the locomotive has advanced a little further, it will, by transmitting a current through
the line-wire back to the last station, set the relay to "safety at that point, and also
set to danger "the relay at the point where the locomotive is entering the block.
Thus a locomotive, in its course along a track divided into blocks, sets the relay at the
point where it enters a block to "danger," and the relay at the entrance of a block it
is leaving to safety."
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I have thus briefly described the operation of the signal system to which the present
improvements. appertain; further information may be had by reference to the United

page_text: States Patent No. 243,619, wherein is described a block system with line conductors
and relays or circuit-breakers of the kind which may be employed in carrying out
this invention.
The objects of the present improvements are to avoid the necessity for employing
insulated sections of the track-rails at the several block stations, and to avoid the
uncertainty in the action of the electro-magret in the signal circuit. which arises from
the sudden shunting of a considerable external resistance into this circuit at the trans-
mitting point.
In effecting these ends, I employ what I call a contact-rail placed on the track and
situated preferably between and parallel with the track-rails; this contact-rail is
insulated from the track-rails and arranged in the path of a movable contact-piece or
-slide on the locomotive. The contact-piece or -slide forms a switch or circuit-controller
which, when the locomotive passes the contact-rail, breaks a normally-closed shunt or
short circuit on the locomotive and simultaneously switches into the locomotive circuit
a partial track circuit, or station circuit, controlled by the relay or circuit-breaker. A
contact-rail is also placed at the transmitting point, where the line circuit is shunted
into the locomotive circuit by the same means. In order that the external resistance
of the line circuit may not affect the operation of the signal magnet, I employ a
signal which may be an ordinary electric bell-in an open circuit and an automatic
circuit-controller, called a distributer, having an external resistance in the circuit with
one of its magnets, the said resistance being equal to the external resistance of the
longest conductor in the line circuit. The function of the distributer is to close the
signal circuit and break the main circuit at the instant the normally-closed main
circuit is broken by the relay at a station passed being set to
66 danger.' The magnet
of the distributer which breaks the main circuit and closes the signal circuit has the
external resistance above referred to in its circuit. The engineer breaks the bell
circuit and closes the main circuit at the distributer by means of a button circuit-closer
or "switch" through the medium of à restoring circuit. hereinafter described.
In the accompanying drawings, Fig. 1 is a sectional side elevation of a locomotive
and a portion of a railway-track provided with the present improvements, the plane of
the section being indicated by the line 11 in Fig. 2. Fig. 2 is a sectional front
elevation of the same, the plane in which the section is taken being indicated by the
line 22 in Fig. 1. Fig. 3 is a detached view shewing, on a large scale, the contact-rail
and the circuit-controller on the locomotive. The dotted lines shew different positions
of the parts. Fig. 4 is a sectional view showing each part of the device with all the
circuits. This view being simply for explanation, the proper proportions of the parts
and their relative positions in practice have been departed from. Figs. 5 and 6 are
views, showing, on a small scale, the arrangement of the line wires and relays at two
adjacent block stations. Fig. 5 represents the locomotive at the entrance to a block
where a signal is received if there is danger ahead. In Fig. 6, the locomotive has
advanced to the transmitting position and is in the act of setting the relay at the next
station behind to "safety." Fig. 7 is a diagrammatic plan view illustrating the
employment of induction in the line circuit of the system. Figs. 8, 8" and 8 show a
modified form of the circuit-controller.
Referring to Figs. 1, 2, 3 and 4, xal are the two track-rails and X is a locomotive
thereon. G is the electric current generator, which I usually mount on the pilot of
the locomotive in a suitable box or casing, and B is the distributer, which is preferably
placed in the same box with the generator G. Sg is the danger signal fitted in the
cab of the locomotive; this signal may be an ordinary electric bell in a normally-open
circuit. R (Fig. 4) represents one of the relays or circuit-breaking devices. Each
consists of a *
safety" electro-magnet S, a "danger" electro-magnet D, an armature
lever carrying the armatures for both magnets, and a contact-piece or -screw m.
These parts may be arranged in various ways. The distributer B (Fig. 4) consists of
"a suitable base on which is mounted a metal post g. In the top of the latter is
pivotted a metal lever bearing two armatures i and
brought alternately into electrical contact respectively
magnets and ("fixed to the same base as the post g.
which, as the lever rocks, are
with the cores of two electro-
A carbon or other resistance n

page_text: is in the circuit with the coils of the magnet C¹. These parts may be arranged in
different ways.
I will now explain the switch or circuit-controlling device whereby the normally-
closed shunt circuit, limited to the locomotive, is broken and closed, and whereby,
simultaneously with the breaking of this circuit, another circuit is established, which
is only partly limited to the locomotive and is controlled by the relay R.
Preferably about midway between the rails & ¹ is mounted a contact-rail A, which
is insulated, and has two inclines lying in opposite directions on its upper face; its
highest point being where these inclines meet, as shown in the drawings. The contact-
rail is placed where it is desired the engineer should receive a signal when danger is
present. On the locomotive, usually under the pilot, I mount a contact-wheel a, which
is rotatively mounted in the lower end of a slide 6 adapted to play up and down in
fixed guides or keepers c c and pressed down by a spring d. Gravity may, however,
be relied upon to keep the wheel a down. The latter is so set with reference to the
inclined contact-rail A that, whenever the locomotive passes a point on the road where
such a rail is situated, the wheel rolls up one incline on the said rail and down the
other, as indicated in Fig. 3. When the wheel a is in its lowest position and is
e, secured
not in contact with the rail A, an insulated metal contact-piece or brush
in any convenient manner to the locomotive, bears against or touches the upper
end of the slide band is in electrical contact therewith; but, when the wheel a
travels up the rail A, a plate f made of insulating material and placed on the
slide 6 is brought under the brush e and the electrical contact is broken.
I will now explain the arrangement of the circuits with special reference to Fig. 4.
P and N represent respectively the binding-posts at the positive and negative poles of
the generator G. The current flows from the binding-post P through the wire 1 to
the post g of the distributer B, thence by way of one arin of the pivotted lever h, the
armature i, the core of the electro-magnet C, the wire 2, the coil of the magnet C,
and through the wire 3 to a binding-post j; thence it flows through the wire 4 to the
brush e, thence to the slide b, and thence through the wiro 5 to the binding-post N at
the negative pole of the generator. The circuit described is normally closed, and is
wholly confined to the locomotive. The wire 4 and brush e form the shunt. When
the locomotive enters a block, the wheel a rolls up the rail A and the slide b is moved
upwards; thus breaking the shunt circuit by reason of the plate f being brought
against the brush e. Instead of flowing through the wire 4 from the binding-post j,
the current flows from the said binding-post through a wire 6 to the wheel k of
the locomotive, thence to the track-rail a, and thence by a wire 7 to the armature-
lever of the relay R, thence to the contact-screw m of the relay, thence by a wire 8
to the contact-rail A, and thence through the wheel a, the slide band the wire 5 back
to the generator. Thus it will be seen that if the armature-lever 1 of the relay is in
contact with the screw m (as in Fig. 4) the circuit will remain closed and no signal ·
"safety
will be received by the engineer. I call the magnet S of the relay R the "
magnet," as it sets the relay to "safety" by closing the circuit. The magnet D of
the relay breaks the circuit and sets the relay to "danger," and I therefore call it the
danger magnet." On reference to Fig. 4 it will be seen that the current flowing
from the binding-post P to the post 9 of the distributer B is divided, a portion of
the current flowing off by way of the wire 9, the coil of the magnet and the
wire 10 to the external resistance n, which is equal to the external resistance of the
longest wire or conductor on the line, and thence through the wire 11 back to the
generator. The circuit through the coil of the magnet is always closed, and, con-
sequently, this magnet is always excited; but, owing to the external resistance n,
the magnet C is less powerful than the magnet C, which is normally excited but is
capable of being demagnetized.
68
If, for any reason, the relay is set to "danger" when the locomotive reaches 'the
receiving point and the contact between the lever and the screw m is broken, then,
when the wheel a rolls up the rail A and breaks the locomotive-circuit by moving the
plate against the brush e, the current cannot flow through the wires 7 and 8 because
of the break at the relay. Consequently, the magnet C is demagnetized and the

page_text: magnet C, which is always excited, will attract the armature into contact, thus
closing the normally-open circuit containing the signal or alarm bell Sg. The current
then flows from the binding-post P through the wire 1, the post g, the lever h, the
armature, the core of the magnet C¹ and the wire 12 to the bell Sg, and thence
through the wire 13 back to the generator. The presence of danger is thus
signalled by the ringing of the bell.
In order to stop the bell from ringing and to again close the main circuit through
the core of the magnet C, a "switch" or circuit-closer Sw is employed, whereby the
engineer may, by simply closing a restoring circuit, send a current through the coil
of the magnet C; the effect of this being to rock the lever h, thus breaking the bell-
circuit and restoring the main circuit upon the contact of the armature with the
core of the magnet C being re-established. Instead of the switch Sw, an ordinary
push-button of the kind known to all electricians, or indeed any spring contact device
which, upon being released, will automatically break the restoring circuit, may be
employed equally well. I have shewn an ordinary lever "switch" merely for con-
venience of illustration. If such a switch were used, the engineer might inadver-
tently leave the restoring circuit unbroken. When the engineer closes the restoring
circuit, the current flows from binding-post P through a wire 14 to the switch or
button Sw, thence, by a wire 15', to and through the coil of the magnet C, thence,
by the wires 3 and 4 to the brush e, and thence through the wire 5 to the binding-
post. N. It will be understood that by the time the engineer has had an opportunity
of manipulating the switch Sw, the wheel a will have again descended, after having
passed over the inclined rail A, so that the brush e will once more be in electrical
contact with the slide b. The wheel a and slide ↳ may both be of metal; the wire 5
being connected directly to the upper end of the said slide. The mechanical con-
struction of these parts is not, however, a matter material to this invention.
The locomotive after passing the receiving point, no danger signal having been
given, advances into the block to the transmitting point, which is usually a short
distance beyond the receiving point. In Figs. 5 and 6, I have also shewn a block C,
parts of two blocks B and D, and stations O and OO, the latter being situated
respectively at the entrances to the blocks and D. The locomotive in Fig. 5 is
shewn at the receiving point at the station O just entering the block C. The locomo-
tive in Fig. 6 is represented as having entered the block C and reached the trans-
mitting point. At the transmitting point is placed a second contact-rail A¹, which
may be exactly like the first contact-rail A. In Fig. 4, this rail is diagrammatically
represented as situated just below the rail A. When the locomotive reaches the
transmitting point, the wheel a rolls up the rail A', and simultaneously breaks the
locomotive shunt circuit (through the brush e) and shunts into the circuit with the
generator G, the coil of the "danger" magnet D of the relay at the station O and
the "safety" magnet B of the relay at the next station behind-that is, at the
entrance to the block B. The current flows (see Fig. 4) from the binding-post P,
through the wire 1 and the parts marked g, h, i, 2, C, 3, 6 and k to the rail, thence
by a wire 15, to the "danger" magnet. Dat the station O and through the coil of
that magnet, thence (see Figs. 5 and 6) back to the preceding station by a wire 16 to
the "safety" magnet S at that station (represented diagrammatically by dotted lines
in Fig. 4), through the coil of that magnet, thence forward by a wire or
other conductor 17 to the contact-rail A', and thence through the wheel a, slide band
wire 5 to the other pole of the generator. The effect of this is to excite the electro-
magnets thus put in circuit and to set the relay at the station to "danger" and
the relay at the preceding station to safety." When the locomotive reaches the
station 00, it sets the relay at that station to "danger" and the relay at the station O
safety."
to "
When the locomotive reaches the transmitting point (the rail A¹), owing to the
increased external resistance in the circuit the attracting power of the magnet C
tending to preserve the contact between its core and armature will be weakened
hence, as the magnet ("¹is always excited, I put an external resistance n into the
circuit with the coil of the magnet C₁ equal to the greatest external resistance that
;

page_text: there may be in the transmitting circuit. Otherwise, the magnet C would over-
come the magnet when the transmitting point was reached, and thus break the
main circuit and close the bell or signal circuit. By the use of the distributer B,
I avoid all difficulties arising from irregularities due to the varying resistance in the
circuits.
This construction also avoids the difficulties and expense attendant upon maintaining
insulations in the track-rails, replacing brushes, maintaining insulation between the
locomotive and tender, and repairing the mechanical devices along the track which are
actuated by the locomotive.
In the drawings, the contact-rails A and A¹ are shewn mounted on the ties or
sleepers partly below the level of the crowns of the track-rails. The height of
the contact-rails is not, however, essential; they may, if preferred, stand above the
level of the track-rails. The height of the wheel a is simply altered accordingly.
The wheel a is merely a rolling contact-piece, and, so long as the inclined contact-
rail serves to raise the slide, or sliding part, and effect the result specified, the con-
struction shewn may be varied without departing from the principle of this invention.
For example, a circuit-controller like that illustrated in Figs. 8, 8" and 8" may be
employed. Fig. 8 is a sectional front elevation, Fig. 8 a detached side view of the
sliding piece b, and Fig. 8b a plan of the railway-track. In this construction, the
inclines or curved surfaces on the contact-rail A2 are arranged at the side instead of
on the upper face; the wheel or contact-piece a being moved laterally instead of
vertically by the said rail. The slide is coupled to an arm of a bell-crank lever
pivotted to the locomotive; the wheel a being mounted at the extremity of the bell-
crank lever. The upper extremity fl of the slide is bevelled, as seen in Fig. 84, and
the insulating plate fis dispensed with; the shunt circuit being broken by drawing
down the slide until the brush e is out of contact therewith. When the wheel a has
passed the rail A2, the slide is raised by the spring ; the contact of the brush e with
the said slide being thus restored.
It will be obvious that the contact-rail may be made to break the shunt circuit
through the medium of a great variety of switches or mechanical circuit-controlling
devices.
The relay R is a well-known device, for which I therefore make no claim.
In the distributer B, I have shewn the cores and armatures of the magnets Cand C
as forming contacts and elements of the respective circuits, but other contacts may be
substituted, as will be readily understood.
Fig. 7 illustrates the application of an induced current in the transmitting circuit.
The wires 16 and 17, instead of being coupled directly with the coil of the magnet D
at the transmitting station and with that of the magnet S at the next station behind,
as before described, are in circuit with the primary coil of an induction coil M, and
the circuit comprising the line wires 16 and 17 and the coils of the said magnets D
and S includes the secondary coil of the induction coil M. The result of this construc-
tion is that the magnets D and S are excited by the current induced in the said coils.
The present improvements may be applied, with or without induction in the circuits,
for actuating a gate at any point along the line. For example, a gate may be provided
where a road crosses the railway; the gate when released being arranged to shut by
the effect of gravity. Upon the locomotive reaching a predetermined point, it closes
a circuit, thereby exciting a releasing magnet at the gate, whereupon the latter swings
round and shuts. When the locomotive passes the point where the gate is situated, it
acts, through a mechanical device, to reopen the gate. The releasing magnet may be
excited by an induced current.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I claim :-
1-A railway-track provided with a contact-rail insulated from the track-rails, a
relay, and a partial electric circuit which includes the armature-lever and contact-
point of the relay and has for its terminals one of the track-rails and the said
contact-rail respectively..

page_text: 2: A railway-track provided with a contact-rail insulated from the track-rails, two
relays situated at different points along the railway, and a partial electric line circuit
which includes the coils of the "danger" or circuit-breaking magnet of one relay
and the "safety" or circuit-closing magnet of the other relay, the said partial circuit
having for its terminals one of the track-rails and the said contact-rail respectively.
3: The combination, with a railway-track furnished with a contact-rail insulated
from the track-rails, a relay, and a partial electric circuit which includes the armature-
lever and the contact-point of the said relay and has for its terminals one of the
track-rails and the said contact-rail respectively, of a locomotive provided with a
partial electric circuit which comprises a generator and has for its terminals a wheel of
the locomotive and a pendant movable contact, a shunt circuit normally closed and
which includes the generator, and a circuit controller actuated by the contact-rail on.
the track and serving to break the shunt circuit and connect the partial circuit on the
locomotive with that on the railway-track.
4:The combination, with a railway-track furnished with a contact-rail insulated
from the track-rails, two relays at different points along the railway, and a partial
electric circuit which includes the "danger" or circuit-breaking magnet of one relay
and the "safety" or circuit-closing magnet of the other relay, the said partial circuit
having for its terminals one of the track-rails and the said contact-rail respectively, of
a locomotive provided with a partial circuit which includes a generator and has for its
terminals a wheel of the locomotive and a pendant movable contact, a shunt circuit
normally closed and which includes the generator, and a circuit controller actuated by
the contact-rail on the track and serving to break the shunt circuit and connect the
partial circuit on the locomotive with that on the line of railway.
5: A locomotive provided with a distributer (B), a normally-closed electric circuit
which includes a generator and the coil, armature and core of one magnet (C) of the
distributer, an electric signal or bell, a normally-open circuit which comprises the
generator, the signal magnet and the core and armature of the other magnet (C¹) of
the distributer, and a constantly-closed exciting circuit which contains the generator,
the coil of the last-mentioned magnet (C¹) and an external resistance (n) substantially
as described.
6: The combination, with a railway-track furnished with a contact-rail at the
transmitting point, two relays at different points on the line, a partial line-circuit
which comprises the coils of the "danger" magnet D of one relay and the "safety'
magnet S of the other relay, the said partial circuit having for its terminals one of the
track-rails and the said contact-rail respectively, of a locomotive provided with a
distributer B, a partial electric circuit which includes the generator and the core,
armature and coil of the magnet C of the distributer, a normally-open circuit which
contains the generator, the core and armature of the magnet C¹ of the distributer and
the electric bell or signal, and a constantly-closed exciting circuit which embodies the
generator, the coil of the magnet C₁ and an external resistance equal to the greatest
external resistance of the line.
7: The combination, with a distributer comprising the electro-magnets C and C², the
vibrating armature lever and armatures and the resistance n, of a circuit which includes
the generator, the coil, armature and core of the magnet C, the signal circuit which
comprises the generator, the signal, and the armature and core of the magnet C', the
constantly-closed exciting circuit which contains the generator, the coil of the
magnet and the resistance n, and the restoring circuit which embodies the generator,
and the coil of the magnet C and the switch or circuit-closer Sw, substantially as set
forth.
8: The combination, with a circuit-changer or switch carried by the locomotive
and comprising a slide b, a contact-wheel a rotatively mounted therein and a brush e
normally in electrical contact with the slide b, the normally-closed shunt-circuit on the
locomotive which includes the wire 4 connected to the brush e, the wire 5 connected
to the slide b, and the generator, and the normally-open partial circuit on the
locomotive which contains the generator and of which the wheel a forms one terminal
and the wheel k of the locomotive the other terminal, of a railway-track provided with

page_text: two contact-rails A and A¹, two similar relays arranged at different points on the track,
each of which comprises a "danger" magnet D, a "safety" magnet S, their armatures,
armature-lever, and contact-point, a partial electric line circuit which embodies the
armature-lever and contact of one relay and has for its terminals one of the track-rails
and the contact-rail A respectively, and another partial electric line circuit which
includes the coils of the magnet D of one relay and of the magnet S of the other
relay and has for its terminals one of the track-rails and the contact-rail A¹ respectively,
substantially as set forth.
9: A locomotive provided with an electric hell or alarm, a normally-open bell-
circuit, a constantly-closed electric circuit which includes the generator, the coil of one
magnet and an external resistance n, a normally-closed electric circuit which comprises
the generator, and an electro-magnet C (the coil of which is embodied in the said
normally-closed circuit), the said magnet when excited holding the bell-circuit open
and its own circuit closed, whereby when the said normally-closed circuit is broken,
the bell-circuit is instantly closed and the alarm sounded.
:
10 In railway block-signals, the utilization of induction in the circuit or circuits;
that is, the utilization of an induced electric current instead of a direct current for
exciting the magnets in the said circuit or circuits.
G. G. M. HARDINGHAM,
191, Fleet Street, London, E.C.,
Agent for the Applicant.