Year: 1897

page_text: A communication from abroad by CHARLES WILLIAM GRANT, of Concord,
Middlesex, Massachusetts, United States of America
I, JAMES GRIEVE LORRAIN, M.I.E.E., M.I. Mech. E., of Norfolk House, Victoria
Embankment, London, W.C., in the County of Middlesex, Chartered Patent Agent,
do hereby declare the nature of this invention (as communicated to me from
abroad) and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement: —
My invention relates to improvements in or connected with railway signals by
means of which certain advantages are obtained.
In the accompanying drawings,
Figure 1 is a diagram representing the plan of a road-bed prepared for use in
connection with my system.
Figure 2 illustrates diagrammatically a section of the said road-bed and a
locomotive equipped with the apparatus required to operate with the corresponding
apparatus on the roadway.
Figure 3 represents a truck having an induction coil suspended therefrom.
Figure 4 represents the core upon which the induction coils are wound and
Figure 5 illustrates the invention as applied to a single track road.
Figure 6 illustrates the part as applied to a draw-bridge, turn-table or turn-out
switch.
My invention is based upon the principle of electro-magnetic induction between
certain stationary coils along the road-bed and certain other coils carried by
the locomotive of a train.
More particularly I place along the road-bed a series of coils provided with
iron cores and arranged in series in a circuit terminating at the two opposite and
insulated rails of a section of track more or less remote whereon an interfering or
obstructing train may be standing or running. These coils are arranged to receive
current in the event of their circuit being closed by the presence of the interfering
train aforesaid from a constantly energized coil carried by the locomotive in a
position where it may act inductively thereon. In the event of the said track
coils being energized they, in turn, act inductively upon a second coil carried by
the locomotive and connected with a bell or other signalling device responsive
to an alternating current. In practice, the track coils will be grouped together
in a series, including those adjacent to one section of track, and the terminals
of their circuit will be connected respectively to the two opposite and insulated
rails of another section of track more or less distant. In operation the constantly
energized primary coil carried by the locomotive, and receiving an alternating
current from a generator located thereon, will tend to induce secondary currents
in the track coils, but such tendency will only become effective in the event of
the circuit of said track coils being closed by the presence of an interfering train
on the distant section, and in such event, the secondary currents in the track

page_text: coils will induce tertiary currents in the signal-receiving coil carried by the
locomotive. In this manner any locomotive will be automatically notified, through
its own coils and its own generator, of the presence of another locomotive, train
or car, within a specified distance ahead of it.
My invention also consists in certain detail of constructon hereinafter set forth
and particularly in certain testing arrangements by which the condition of the train
apparatus may be constantly indicated and any failure or disarrangement be
immediately disclosed.
The advantage of my system lies principally in the fact that there is no
apparatus along the track containing any moving parts and the system, so far as
the track is concerned, depends only upon fixed coils and conductors which,
when once properly installed, are not liable to injury by weather or temperature
or to disarrangement in operation. There are also no stationary batteries or
generators along the track, and such current as is employed is derived from a
low frequency alternating current dynamo of a simple type placed on the locomotive,
while the remaining part of the apparatus carried by the train is free from com-
plications and is under the constant supervision of the engineer. It is also of a
character not at all liable to disarrangements of any kind.
Referring to the drawings, A A¹ A² represent three insulated sections of railway
rail and B B 13 represent corresponding sections of the opposite rail. Between
the two rails of each section, on a uniform level, I place a series of coils CC C,
which are preferably wound on rectangular iron frames of the form shown in
Figure 4 and I connect together in series all of the coils in any one section. The
two terminals of the coils thus grouped together are extended along the track and
connected respectively to the rails of another section more or less distant, preferably
the second section ahead. Thus, in Figure 1, the coils C C, etc., shown in full
lines as placed between the rails A and B, are connected in series, and their
terminals connected to the rails A and B32 of the next section but one in advance.
Similarly the coils (shown in dotted lines) between sections A and B will be
connected to the rails of section A³ B.
If it is desired to work in both directions on a single track, there will be
required two sets of coils C, C, etc., the coils of one set alternating with those of
the other set, and the terminals of one set connecting with rail sections in advance,
and those of the other set with rail sections in the rear. Thus, referring to
Figure 5, there are shown between the rail sections A2 132 two series of coils CC, etc.,
and CC, etc., the former series connecting with the rail sections A and B and
the latter sections with the rail sections A and B. With the arrangement
described it is obvious that, in Figure 1; for instance, a train on rail sections A B
will close the circuit of coils C, C, etc., between rail sections A and B, while in
Figure 5 one set of coils will have their circuit closed by a train on A 13 and
the other by a train on a set A B. Moreover, I may arrange that any unusual
circumstance, such as the opening of a drawbridge, or the throwing of a turnout
switch, in any section will operate to close a circuit between the two rails and
thereby complete the circuit of the track coils connected with said rail. Thus
in Figure 6, M represents a drawbridge or turntable in rail sections A* 13+, and
it is so arranged that, when moved from its normal position shown in the drawings,
the projection m no longer presses upon the spring switch P' to keep it in its open
position. Switch P is now released and arm p makes contact with stud so
as to close the circuit between rails A and B, in which event an approaching train
will receive a signal in the same manner as it would if the rails A and B were
connected by a train standing or running thereon.
Referring to Figure 2, I have shown the track coils C C, etc., as laid in the
roadway flush with the upper surface of the ties or sleepers DD, the centre one
of the five coils being shown in section, in order to illustrate the construction of
the coil which, as I have already stated, is wound about a rectangular frame
grooved on its periphery to receive the wire. A coil E of similar construction
is carried on one part of the locomotive, for instance, underneath the tender, being

page_text: suspended directly from the axles, or any fixed point, as shown in Figure 3, in
order that it may be held at an invariable distance away from, but in close proximity
to, the track coils C C. The track coils may be as numerous as desired, although
their number will naturally be limited by the length of the coil carried on the
tender, and the frequency with which it is desired to receive indications from
the section ahead. This coil E is connected directly with an alternating current
generator F on the locomotive, which will be constantly running and sending
at all times an alternating current through the coil. A similar, but smaller,
coil E' will be carried at a remote point of the locomotive, for instance, directly
under the pilot, or forward track, so as to be free from the inductive influence of
the primary coil E. This coil E' will be suspended just like E at a fixed distance.
from the track coils C C, etc., and its line circuit will include a bell G, or other
device responsive audibly to an alternating current. .The circuit of coil E will
be controlled by an ordinary switch H and the circuit of coil E by a similar
switch I.
The operation of the apparatus thus described will be obvious. The generator F
will keep the coil E constantly energized by an alternating current, which, in
turn, will induce secondary currents in the track coils C C, etc., provided there is
an interfering train in the neighbourhood, on the section of track to the rails of
which the coils C C are connected. When such an induced current passes in the
coils CC they will act inductively to produce a tertiary current in the coil E¹
that will serve to operate the bell G.
Referring again to Figure 2, it will be observed that just above the coil E and
in close proximity thereto is a similar, but smaller, coil N, having a magnet 0
included in its circuit which circuit is controlled by a switch J. The purpose of this
coil is to serve as a continual test on generator F and primary coil E. So long as the
normal current is passing through the said generator and coil, a secondary current
will pass through coil N and magnet 0 and maintain in its attracted position,
the armature of the said magnet, which, in turn, controls a mechanical bell L.
If, for any reason, there is an interruption of the usual current in the primary
circuit, it will be followed by a cessation of current in the secondary circuit and
the magnet O will hence release its armature, allowing the bell L to ring. I have
also provided a switch K by means of which can at any time throw the coils E
and E, the bell G and generator F, into a common circuit in series. I thus
provide means for testing the integrity of coil E' and the operativeness of bell G
at any time. In the position of switch K, shown in the drawing, the two circuits
are independent of each other, but if the switch be moved upwards so as to throw
the switch arms into contact with the connected points R R respectively there
will obviously be a series circuit provided through the several parts of the apparatus
above described.
It is possible also to place one or more track coils in a local circuit along the
line for the purpose of signalling at crossings and at other points where it is
desired to give warning of an approaching train. In Figure 1, I have shown
two sets of coils in section A³ B³ which are connected with a local circuit including
a bell S.
I am aware that it has been heretofore proposed to communicate with a moving
train by means of a line wire extending along the track and acting inductively upon
a coil on a train. I have, however, ascertained by experience, that such a system
is impracticable, at least for audible signalling purposes, and that it is essentia!
to employ a series of coils capable of acting with considerable inductive strength
upon each other.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what I
claim is:-
-
1. The combination in a railway signalling system of a series of coils located

page_text: of a neighbouring section, a generator on the train for energizing the said coils
by induction and a receiving coil carried by the same train in proximity to the
said series of track coils and connected with signal receiving apparatus on the
train, substantially as and for the purpose set forth.
2. The combination in a railway signalling system of a series of coils provided
with iron cores located along a section of railway and having their terminals
connected to the track rails of a neighbouring section, a generator on the train
for energizing the said coils by induction and a receiving coil having an iron core
carried by the same train in proximity to the said series of track coils and con-
nected with signal receiving apparatus on the train.
3. The combination in a railway signalling system of a series of track coils
having their terminals connected to the opposite insulated rails of a neighbouring
section of the track, an alternating current generator carried by the train, a coil
on the train in the circuit of said generator carried at a point adjacent to the
track coils, so as to induce current therein, and a receiving coil also on the train
carried in a similar position and provided with signal-receiving devices, sub-
stantially as and for the purpose set forth.
4. The combination in a railway signalling system of three adjacent sections
of track, the rails of each section being insulated from those of the other sections,
a series of track coils arranged along the first of the said sections, two insulated
line wires connected to the terminals of said coils respectively and extending along
the second or intermediate one of the said sections and connectel respectively
to the insulated track rails of the third or last one of the said sections, an alternating
current generator, an inducing coil in the circuit of said generator forming a
primary coil for inducing an alternating current in said track coils, a receiving
coil carried by the train in proximity to the said track coils so as to receive a
tertiary induced current in the event of the circuit of said track coils being closed,
and signalling devices on the train included in the circuit of said receiving coil,
substantially as and for the purpose set forth.
5. The combination in a railway signalling system of three adjacent sections
of track, the rails of each section being insulated from those of the other sections,
a nlurality of track coils connected in series in a common circuit and arranged
in a single line adjacent to the first of the three sections aforesaid, two insulated
conductors, one connected at the beginning of the said first section
to the terminal of the first one of the said track coils and the other
connected at the end of the same section to the terminal of the last of the said
track coils, the two conductors extending from their said connection points along
and beyond the second or intermediate one of the said three track-sections and
connected respectively to the two insulated rails of the third or last one of the
aforesaid three track sections, an alternating current generator, an inducing coil
in the circuit of said generator, forming a primary coil for inducing an alternating
current in said track coils, a receiving coil carried by the train in proximity to
the said track coils, so as to receive a tertiary induced current in the event of the
circuit of said track coils being closed, and signalling devices on the train included
in the circuit of said receiving coil, substantially as and for the purpose set forth.
6. The combination in a railway signal system of a series of track coils, an
inducing coil carried by the locomotive for generating current in said track coils,
an alternating current generator. energizing the said inducing coils, a test coil
placed adjacent to the said inducing coil, and indicating devices in the circuit
of the said test coils, substantially as and for the purpose set forth.
7. The combination of track coils C C, etc., an inducing coil E carried by the
train in proximity to the said track coils indicating coil N, generator F, normally
energizing coil E, magnet O in the circuit of coil N, and a signalling device L
controlled by said magnet O, substantially as and for the purpose set forth.
8. The combination with one or more car axles of a railway vehicle, of an
inducing coil suspended directly therefrom, a series of track coil arranged at
pr near the surface of the road-bed in proximity to the said inducing

page_text: coil, a generator on the train for energizing the inducing coil and a
signalling device on the same train inductively operated by the said track coil,
substantially as and for the purpose set forth.
9. The combination with an induced track circuit formed in part of the track
rail and in part by a conductor subject to inductive action, of a generator on the
train for supplying the said circuit with alternating current and a signalling
circuit on the same train energized inductively from the said track circuit, sub-
stantially as and for the purpose set forth.
10. The combination in a railway signalling system of an induction circuit
along the railway formed in part by insulated sections of track rail, a drawbridge,
or turn-table, in said section, a switch controlled by the said drawbridge,
or turn-table, for closing the circuit between the two rails in the event of the
bridge, or turn-table, being open, a generator on the train for inducing an
alternating current in said track circuit and signalling devices on the same train
operated by the said induced current, substantially as and for the purpose set forth.
11. The combination in a railway signalling system of a railway track having
its rails divided into three or more insulated sections, two induced circuits adjacent
to one section and connected respectively with the section in advance and in rear
thereof, a generator on the train for inducing alternating currents in said circuits
and signalling devices on the same train operated by said induced circuits, sub-
stantially as and for the purpose set forth.
12. The combination in a railway signalling system of a line of track coils
adjacent to a section of railway, said track coils being included in a normally
open circuit, an inducing coil and a receiving coil carried by the same train
and arranged in the same longitudinal line adjacent to the line of track coils and
means for closing the track coil circuit by the presence of a neighbouring train..
13. The combination in a railway signalling system of a series of section track
coils on one section, a circuit for said coils controlled by a train on a neighbouring
section, local track coils, a local circuit therefor, a signalling device in said local
circuit and an inducing coil for energizing both the local track coils and section
track coils, substantially as and for the purpose set forth.
Dated this Q1at dove of Ananot
1807