Improvements in Electric Signalling Systems and Apparatus for Railways
Year: 1889

page_text: COMPLETE SPECIFICATION.
Improvements in Electric Signalling Systems and Apparatus
for Railways.
A communication from abroad by THOMAS PARRAMORE WORRALL, of West Chester, in
the State of Pennsylvania, United States of America, Gentleman.
I, PHILIP MIDDLETON JUSTICE of 55 and 56 Chancery Lane in the County of
Middlesex Fellow of the Institute of Patent Agents, do hereby declare the nature of
this invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
This invention has reference to improvements in electric signalling apparatus for
railways and consists more especially in providing a system which is adapted to give
automatically an audible signal upon the locomotive, the giving of such a signal
depending upon the condition of a circuit or series of circuits external to the cab or
locomotive and connected with extra insulated conductors along the railway track,
with which brushes or other suitable devices upon the locomotive make connection
successively.
The audible signal is designed to be a danger signal, and the absence of any signal
will indicate the absence of danger along the line.
The element of safety in the use of the system is that the signal is arranged to be
sounded when any one of the circuits along the line is open. This avoids the danger
of a break in one of such circuit being overlooked, as such a break will, in the working
of the system, be detected and serve to warn the engineer of some sort of trouble or
danger the exact nature of which can be determined afterwards.
It is now generally agreed that the use of visual signals alone for giving information
to an engineer is inadequate and that it is necessary to provide such a signal as will
attract the attention of the engineer under any of the conditions to which such an
officer is liable to be exposed. For this reason it is proposed to provide an audible
signal which will be either a bell located in the cab of the locomotive or a whistle
pitched in a shriller key than the ordinary locomotive whistle. In practice the track
which is to be provided with the system and apparatus is divided into sections and
between the rails of each section insulated conductors are arranged in pairs, and to
these the electric circuits are joined. The arrangement is such that when a locomotive

page_text: provided with the brush passes over the track, it automatically opens the track or
external circuits upon its own section so that a train following immediately behind it
would be warned of danger. On passing to the next section or some succeeding
section, the same locomotive will automatically reclose the circuits which it has, opened
and will, therefore, cause no signal upon a locomotive following at a proper distance.
The result is that no two trains running in the same direction can approach each other
nearer than the length of one, two, three or more sections, according as the system
may be arranged without the engineer of the rear train being warned of danger.
The terminals of one or more of the external circuits may be connected with one of
the bolts of a draw bridge, or with a switch, or a culvert, or any part of the road
where there is a special reason to expect danger, in such a manner that when the
structures are in their normal condition,such.external circuits shall be closed and when
the danger that is feared intervenes the circuit shall necessarily be broken.
In such a case the occurrence of an accident which would endanger a train may
be signaled to any suitable distance from the location where the accident takes
place and the train may be stopped. Moreover, in a case of sudden accident, where
it becomes necessary or desirable to signal to an approaching train and where there
is not time enough for a flagman to give such a signal, means are provided whereby
a signal can be sent by a manual rupture of one of the circuits connected with one
pair of the conducting rails.
The invention is illustrated in the accompanying drawings, in which :-
Fig. 1 is a diagram of the circuit external to the locomotive and the track
apparatus.
Fig. 2 is a diagram forming practically a continuation of Fig. 1.
Fig. 3 is a diagram of the circuits on the locomotive giving details of the brushes
and their connections.
Fig. 4 is a detail, and
Fig. 5 illustrates a circuit closer which may be used 'in connection with the
system.
Referring to Fig. 1, A is a railway track, and B, C, D, E, are different-sections
thereof, each section being provided at suitable intervals with conducting rails.a, a' b, b²,
etc., arranged in pairs between the ordinary running rails of the track. These con-
ducting rails are insulated from each other. It will be seen that the rails a, a, form
the terminals of a circuit which passes through armature k and front stop of an
électro-magnet K, while the rails b, b', 'form the terminals of a circuit that is closed
through an electro-magnet L.
The circuit of the magnet K passes, it will be observed, through the magnet 'M
opposite section D to the conductor, and in the other direction to the conductor f.
Passing to the conductors c, d, and d, d, the connections are similar to those of the
conductors just mentioned. These conductors 'bear the same relations to the
magnets N, O, P, that the conductors last described bear to the inagnets K, L and M.
There are similar connections also for the magnets Q and R, and also for the
magnets S and T, as shown in Fig. 2.
Now it is evident that if all the armatures are on the front stops of the
magnets S, K, N, Q, R,.etc., that all the circuits connected with the supplementary
rails will be closed outside the cab of the locomotive. The circuits within the loco-
motive are illustrated in Fig. 3, U and V in that figure being the brushes which make
contact with the conducting rails already referred to. "These brushes are pivoted 'in-a
frame W, which is secured to the bottom of the locomotive by any suitable means.
The brushes are metallic and held in metallic heads, which are secured 'to non-
conducting posts u, v, being thus insulated from each other. On the top of the post u
is secured a metallic head which is cut away centrally, the cut away portions being
filled with insulating, material on which a spring Y rests when the brush post is in a
vertical position. The posts assume this position when free, being held there by the
springs, When the brushes come into contact with the conducting rails the
posts are tilted and at that time the spring Y comes into contact with the metallic
portion of the head X.

page_text: Such is the mechanical construction of the brushes and the parts immediately
connected therewith. The circuits run from the brushes to the battery Z, on the
locomotive, the circuit from one brush passing through an electro-magnet o. The
circuit froin the head X passes to one pole of the same battery through an
electro-magnet p, while the circuit from the spring Y passes to the other pole of
the battery through the armature o¹, and the back stop o² of the magnet o. The
bell is joined on one side to the battery and on the other to the front stop of
the magnet P
whose armature is joined to the other pole of the battery.
The operation of the parts described is as follows:
Suppose a train to be moving towards the left in Fig. 1, with a locomotive having
applied to it the apparatus shown in Fig. 3. When the brushes come into contact
with a and a', if the external circuit is closed in the manner indicated in Fig. 1, a
circuit will be formed for the battery Z through the magnet o, causing that magnet
to be energized so as to attract its armature. This action serves to break connection
between of and o. Accordingly when the head X is moved over into contact with
spring Y, the circuit of which those parts form terminals is broken at o', o³, and no
connection takes place at magnet p. It being evident that the energization of the
said magnet p is what closes the bell circuit for sounding a signal, it is thus also
evident that no signal will be sent in the conditions of things just described.
Suppose, however, that the external circuit had been found broken or open from
any cause, the battery would have found no circuit through o and accordingly the
armature o would have remained against the stop o under the influence of this
retractile spring. In that case the circuit of battery Z would have been closed by
the head coming into contact with the spring Y, the magnet p would have been
energized and the bell circuit completed, causing a sound of warning to the
engineer.
Now every engine that is provided with this apparatus, on proceeding further
along the section, comes to the position where its brushes are in contact with 6, 6', and
breaks the circuit running from a, a, by energizing the magnet Land tilting the
armature between L and K over to the side of L. Therefore if a following engine
comes along before the first has left section A, it will find the external circuit,first
described open and will receive a warning of danger. The same thing happens at
every section. When, however, the train.has gone far enough beyond the point where
it.opened the original circuit to be out of dangerous proximity to a train coming
behind it, it closes the external circuit through the magnet K, and restores the circuit,
so that a train coming along will find the apparatus set to safety. In the present
instance the terminals of the magnet K are shown as connected to f, f, but it is
obvious that they might be carried still further along so as to maintain a greater
safety distance between trains running in the same direction. Moreover, it is obvious
that any two conducting rails forming a pair, as g, g, for example, might be con-
nected to a bolt of a draw-bridge or to a culvert or other railway structure in such a
manner that when the bolt was withdrawn or the culvert broken the circuit might
also be ruptured and a warning of danger thus given.
In place of the bell- a whistle of shriller tone than the ordinary railway whistle
may be used, in which case the circuit controlling the whistle should normally be
kept closed and the movement of the armature of magnet P should open the said
circuit and release a valve to allow the whistle to blow. This however is a matter
of detail.
In Fig. 4 is shown a. pair of conducting rails a, a', mounted upon a common
insulating support. This support may be of wood or any other good insulating
material.
Fig. 5 shows a circuit closer having a special object. The device consists of a
roller mounted in a yoke which is attached to a suitable support m. A shaft m¹
passes through a slot in this support and serves as the axis of two discs or rollers on
opposite sides thereof. Each of these discs rests upon a spring as n¹, one of these
springs being a circuit terminal located at a short distance from the corresponding
terminal . These terminals are connected, as will be seen, with the circuit of a local

page_text: battery (Fig. 1) which is external to the locomotive, and which includes the
magnet L. There is the same arrangement in connection with the magnet O, M,
and P, and so on. The object of this arrangement is to provide means whereby any
engine or truck which may come along unprovided with the described locomotive
apparatus may set a danger signal, so as to keep engineers on the look-out. The
roller is arranged in such a position that it will necessarily be set by a passing engine
and set the signals to danger.
The magnets at the left of the armatures in Fig. 1 may be regarded as danger
magnets, while those at.the right may be called safety magnets.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed as communicated to me
by my foreign correspondent I declare that what I claim is :-
1. In an electric signalling system for railways track terminals and a partial
electric circuit connected therewith, corresponding train terminals and a partial circuit
connected therewith and passing to a battery on the train through an electro-magnet,
in combination with a separate circuit controlling a signalling apparatus through the
armature and back stop of the said magnet, the said separate circuit being normally
open between two points, but closed at those points when the contact devices on the
train are upon the road terminals, whereby, if the external circuit be found closed a
signal upon the locomotive will be prevented and if found open a signal will be
sounded, as and for the purpose set forth.
2. The combination with conducting rails along a railway track, of corresponding
contact devices upon a train, the said devices being attached to one or more
movable or tilting supports and a circuit controller operated directly by the movement
of said tilting supports to close a circuit upon the train, as and for the purpose
set forth.
3. In an electric signalling system for railways the combination with a danger
circuit external to a railway train, of a circuit controller for the same, the said
circuit controller being provided with projecting parts with which a passing"
train necessarily makes contact to operate the circuit controller, as and for the
purpose set forth.
4. The combination with the contact brushes and the supporting frame in which
they are pivoted, of the battery Z, the partial circuit containing the magnet o, and the
secondary circuit controlled by the said magnet and having as its terminals the
head X and the spring Y, as and for the purpose set forth.
Dated this fith day of March 1980
PHILIP M. JUSTICE.