Automatically Controlling the Action of Railway Signals.
Year: 1891

page_text: Date of Application, 24th June, 1891
Complete Specification Left, 22nd Apr., 1992-Accepted, 4th June, 1892
PROVISIONAL SPECIFICATION.
Automatically Controlling the Action of Railway Signals.
WILLIAM EDWARD LANGDON, Electrical Engineer, Midland Railway, Derby,
do hereby declare the nature of this invention to be as follows:-
:-
In the automatic control of signals for the protection of railway trains, engines
&c., when standing upon a wrong line or a section of line where such trains engines
or vehicles may prove a source of danger to other like trains engines &c.; or be
themselves in danger from other trains engines &c.
The primary object of this invention is to make provision against accidents
which may possibly arise from trains or engines or vehicles being shunted or left.
standing upon the opposite or wrong line of rails. But it may also be employed
for the protection in a similar manner of vehicles standing or travelling upon any
road.
To effect this I apply to the lever working the home signal, or other desired
signal for the section of line, or to the signal itself, an electric locking arrangement
by which the signal or lever becomes locked during the time a vehicle is standing
upon the road protected by it. This locking apparatus so arrange that in its
normal condition the electric current is flowing, and the lock is thereby held off,
leaving the lever or signal free to be worked, but so that any cessation of the
current, whether produced intentionally, by accident, or by failure of the apparatus
will at once bring the lock into play and lock the signal or lever in the "
"danger" position.
on or
At a convenient point in connection with any signal or other levers in the signal
frame which it may be desirable should not be operated during the presence of a
vehicle on the section I arrange a caution board or indicator which is nominally
held in its position clear of the levers by the electric current operating the lock on
the home signal, or signal lever, or by an independent current as may be found
most effectual, but which indicator is, on the cessation of the current set free to fall
and obstruct the operation of such levers.
The battery or batteries are so arranged as to have either the lock and indicator
in the same circuit or to form an independent circuit for each. In either case the
poles of the battery are connected also to the two rails forming the road, protected
by the home or other signal-the positive pole to one rail, and the negative to the
other. Thus each battery has two circuits-one with its instruments in circuit, the
other with the rails, but to a great extent broken by the space between the rails.
The instrument circuit being complete or closed will be active, and the lock and
indicator will be held off, leaving the home signal and other levers to be operated
as may be desired, so long as there is no vehicle standing upon the same road; but
on a train, engine, or other vehicle being placed upon the said rails, the batteries.
will be short circuited by means of the metal connection formed between the rails
by the wheels and axles &c. of the said vehicles; and the current being
withdrawn from the electric lock and indicator those parts will be brought into
operation and remain so until the connection between the two rails becomes again
removed.
The signal will be locked and the indicator will obstruct the operation of such
other levers as may be needed.
In order to insure against short circuiting from other rail connections I, where
necessary, insulate the metals, so as to break their electrical continuity and thereby
confine the operation within any given space.
Dated this 23rd day of June 1891.

page_text: COMPLETE SPECIFICATION.
Automatically Controlling the Action of Railway Signals.
1, WILLIAM EDWARD LANGDON, Electrical Engineer, Midland Railway,
Derby, 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 consists in the mode of and apparatus for the automatic control
of signals for the protection of railway trains engines and the like when standing
upon a wrong line or a section of line where such trains engines cr vehicles may
prove a source of danger to other like trains engines or the like or be themselves in
danger from other trains, engines of the like.
The primary object of this invention is to make provision against accidents
which may possibly arise from trains engines or vehicles being shunted or left
standing upon the opposite or wrong line of rails but may also be employed for
the protection in a similar manner of vehicles standing or travelling upon any
road.
To effect this apply to the lever working the home or other desired signal or
to the signal itself an electric locking arrangement by which the signal or lever
becomes unlocked and stands at danger during the time a vehicle is standing upon
the road protected by it. This locking apparatus I so arrange that in its normal
condition that is when the circuit through the locking apparatus is complete and
the current in operation thereon the lever or signal is free to be worked but so
that any cessation or material reduction of the current whether produced
intentionally, by accident, or by failure of the apparatus, shall at once break or
produce a connection between the two parts of the lock and so allow the signal to
go to "danger."
Figure 1 of the accompanying drawing is a perspective view of a signal post
with my invention applied thereto.
Figure 2 is a detail view to an enlarged scale of the locking device therefor.
Figure 3 is a detail view to an enlarged scale of another modification of locking
device.
Figure 4 is a detail end view showing the unlocked position thereof.
Figure 5 is a similar view showing the locked position.
Figure 6 is a side elevation of an instrument shelf with the apparatus for
operating the caution shield O.
Figure 7 is a front elevation thereof.
Figure 8 is a diagramatic view showing the entire system and
Figure 9 is a diagramatic view of a modification thereof.
Referring to Figure 1 the signal post is provided with arm which as usual has
the weight y but otherwise operated by the crank n³ and rod 3 together with the
other ordinary connections by rods or wires such as are generally used for
operating signals. C is the lever to which these rods or wires in connection with
the lever in the signal box are connected. A and B are plates of metal arranged
to work upon the centre D. The rod is connected to the back plate A. É is
the magnet of an electrical locking arrangement by means of which under certain
conditions the plate B becomes interlocked with the plate A. When this is so the
signal may be operated by the lever C, but when it is not so then the arm is free
to go to the "danger' or "stop" position under the influence of the weight y.
When an engine or other vehicle is standing on the line or that section of it
desired to be protected connection is made between the two rails by the wheels and
axle of the engine and the rails being in the circuit with the signalling device the:
current thereto is either greatly weakened or switched off so that as described the
signal automatically goes to danger irrespective of the position of the lever in
the signal box all as to be hereinafter more fully described.
37

page_text: Referring to Figure 2, A is the back plate to which the signal rod ³ is attached.
B the front plate operated by the signal lever in the signal cabin. E E is an
electro magnet and a is a lever which carries or forms the armature and is centered
at The hook or trigger piece F is mounted on a stud band is connected to the
arinature a by a pin m working in a slot in said armature. a is a stop on the
plate B to prevent the armature from dropping too far. G and H are two slots or
recesses in the plate B to admit the studs and s fixed to the plate A if necessary
with the object of preventing binding by friction, the studs may be provided with
a roller or be otherwise shaped so as to enable it to hold on or to free itself from
the hook F at its point or catch d. The armature bar a is provided with a lever
or arm a near its pivot the object of which is to make or break the electrical
circuit of the coils E by any of the ordinary methods for so doing when the
lever a is in the position shewn in the figure the electrical circuit is broken.
When A and B are shut together the circuit is closed by the lever a passing from
an insulated position to an uninsulated point thereby closing the connection with
the coils E at contact c. This arrangement is purely for economising the battery
power and may or may not be used; the coils may be placed in direct and
permanent connection with the other portion of the circuit as may be found
desirable. The spring a³ is for the purpose of nullifying the concussion of the
armature a on the magnet E when the plate B is suddenly lowered and the stud t
strikes the armature a.
The operation of these parts is as follows the plates A and B being dissociated
as shewn, in order to interlock them it is necessary to lower B to cover A. In
doing so the pin t passes into the slot H and lifts the armature a until it completes
the electrical circuit with the coils E, but before this condition is reached the stud
or roller s passes into the slot or groove G. As the stud t proceeds it lifts the
armature and the latter acting on the hook picce F cants it so that the catch d
passes under the mouth of the groove G as soon as the studs has passed into it.
Now on the stud t completing its movement the arinature is in close proximity to
the cores of the electromagnet E and the lever end a² makes contact with c. The
current now flows through the coils and the catch d on the hook piece is held
under the studs thereby preventing it from falling and so locking B to A.
Whilst
in this position the two parts form one part as it were, and can be moved together.
But if anything occurs to break the electrical circuit or to prevent or greatly
reduce the current flowing through the coils E the armature a will no longer be
sustained by the magnet E and will fall away so that the hook part F will be free
to pass to the position shewn in the figure and the part B will then be separated
from A, the signal arm moving to "danger" by the action of the weight y.
Figures 3. 4 and 5 shew a modified form of apparatus for effecting the same
result. Figure 3 represents that portion of the signal post to which the locking
apparatus may be attached.
A and B are the two metal plates both centered at D. A has a slot G cut in it.
t is a pin fixed as shewn beneath G. On the plate B is mounted an electro
magnet E with its armature a pivoted at and carrying (Figure 4) a rectangular
bars having at its extremity a roller or rounded bar s the object of which is to
In the
engage with the plate A when it is caused to pass through the slot G.
periphery of the plate B there is cut a slot H in the neighbourhood of which
centered at is a contact piece g the contact taaker of which g' is influenced in one
direction by the helical spring k until stopped by the pin g². This it will he
understood is also entirely an economiser of battery power, its object being to
bring the battery current into operation only when required. It may be used or
not as desired.
The operation of this arrangement is as follows. To interlock the two parts,
B has to be lowered into position with A. In lowering B the rollers traverses the
plane of plate A until it drops into the slot G. At the same time the pint passes
into slot H and pressing upon the contact piece g draws the contact tongue g over
into contact with the stud c of the insulated plate c¹ thereby completing the electric

page_text: circuit through E. The magnet E is now active and the armature a is drawn
down to its poles and the locking bar s with its roller or rounded bars engages
(Figure 5) with the back plate A at the slot G so that the one plate cannot move
without the other.
Thus the signal can again be operated in the usual manner.
But if now the
current be broken, the coils E will lose their magnetism and the armature a will
under the weight or pressure of plate A. fall away from its poles, the rollers will be
thrust out from the slot G and the signal will go to "danger."
Either of these arrangements may be applied to the signal post or to any part
of the apparatus working the signal at any point between the signal lever and the
signal arm and although I have only described two modes of locking and unlocking
plates A and B it is evident that the said locking and unlocking may be effected in
other ways witliout departing from my invention.
At a convenient point in connection with any signal or other levers in the signal
frame which it may be desirable should not be operated during the presence of a
vehicle on the section of line I arrange a caution board or indicator which is
normally held in its position clear of the levers by the electric current operating
the lock on the home signal or signal lever or by an independent current as may
be found most effectual, but which indicator is on the cessation of the current set
free to fall and obstruct the operation of such levers.
Figs. 6 and 7 represent the arrangement adapted to operate the caution shield
or indicator placed in the signal cabin over the signal lever M. Immediately over
it attached to the under portion of the instrument shelf or other convenient place
is an electro magnet N and arranged in front of it is the screen or shield O
centered at and provided with a shoulder piece or stop o¹ so that it cannot be
drawn forward beyond the vertical position. To the armature P, normally held
away from the magnet N by the tension spring n is attached a catch piece p and to
the back of the screen O another catch piece 7, so that it shall engage with
whenever said catch p is in a position to do so, that is whenever the armature is
held over to the pole pieces of magnet N.
י
Now assuming that a current is flowing through the magnet N and that the
armature P is attracted to its poles and that the screen O is in the dropped or
vertical position shown by the dotted vertical line, then in order to place it out of
the way to enable the signalman to operate the lever M, it is necessary to push it
back till engages with when it will be held up so long as a current of the
necessary power flows through N. Under this condition the signalman can
operate his lever without obstruction but on the current passing through the
magnet N being cut off or reduced so as to release the armature the spring will
draw it away and the catches and will disengage and the screen O will fall,
thereby indicating that the signal has been placed at "danger" by reason of
connection being made between the two rails on some part of the section of line
electrically connected.
The battery or batteries are so arranged as to have either the lock and indicator
in the same circuit or to form an independent circuit for each. In either case the
poles of the battery are connected to the two rails forming the road protected by
the home or other signal, the positive pole to one rail and the negative to the
other the instruments being joined in between the one pole and the rail opposite to
that to which the same pole of the battery is connected. Thus each battery has
two circuits. One with a metallic circuit composed of the connection with the rail
and its instruments the other with the two rails, but to a great extent broken by
the space and material between the rails. The instrument circuit being complete
or closed will be active, the plates A and B will interlock, and the indicator C
will be held off leaving the home signal and other levers to be operated as may be
desired so long as there is no vehicle standing upon the said road but on a train
engine or other vehicle being placed upon the said rails the current of the batteries
will be short circuited by means of the metal connection formed between the rails
by the wheels and axles of the said vehicles and the current being thus withdrawn

page_text: from the electric lock and indicator, those parts will no longer be held together and
will remain dissociated until the connection between the two rails is again removed,
that is, the signal will go to "danger" and the indicator will fall over the lever
handle.
V to W
:
Fig. 8 illustrates diagramatically the entire system and regarded with the.
preceding illustrations and description thereof will make clear its action.
is a section of line which it is desired to protect as described. e and w are the rails
on which the railway vehicles travel. At connect one pole of the battery Z.
From the opposite pole I carry the connection to the rail w, and I also connect
up to the indicator or screen instrument placed in the signal cabin, here shown
as N. O. P. and to the same pole I also connect the signal lock A. B. the opposite
poles or connections of the indicating apparatus N. O. P. and the locking
apparatus A. B. I connect to the metal as shown at . The instruments N. O. P.
and A. B. may be joined up in parallel as shewn in series or they may be each
worked off an independent battery similarly connected up. If necessary the rails
may be insulated at crossing points so as to insure the required amount of electrical
resistance between vand in order when no vehicle is standing on the rails to
ensure a current of sufficient strength flowing through the instruments N. O. P.
and A. B.
む
Now on a locomotive engine, or other vehicle the flanges or periphery of the
wheels of which are in metallic contact through the shaft of the wheels passing on
to these rails and to the battery Z will be short circuited and its influence on the
instruments N. O. P. and A. B. will be so reduced that it will fail to operate
them. This being so, the screen O (Fig. 6) over the lever M will fall and the
lock holding the metal discs A and B (Figs. 1 to 5) will disengage and the
signal arm will go to "danger" protecting the vehicle upon the section of line
indicated. The same will apply to all sections so provided for whether portions of
the main line sidings or crossings.
As in some instances the wheels of railway vehicles are not made entirely of
metal and that when thus made they would not afford metallic contact through the
shaft of the wheels, one with the other, I overcome this either by connecting the
shaft with the periphery or flange of the wheel by metal strips or wire, or I lay a
metal rod or bar alongside one of the rails so that the flange of the wheel in
passing between the main rail and the bar or subsidiary rail shall make contact
with both and thus short circuit the battery. Fig. 9 illustrates this provision. In
lettering and its general arrangement it is identical with Fig. 8 with the exception
that the contact or subsidiary rail takes the place of the rail w. in Fig. 8 as far
as the electrical connections are concerned.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
First. In connection with a signalling device the application and use of a
compound locking apparatus the component parts of which are electrically and
automatically locked and unlocked and the signal put automatically to the position
of "danger by means of the connection made by the engine or other vehicle when
present on the section of road to be protected the electric-circuit to the locking
apparatus being then broken or the strength of the current materially reduced
substantially as set forth.
Second. The method of arranging the electrical circuit so that when no engine
or other vehicle is on the section of line to be protected the battery current shall
be capable of maintaining the connection between the two parts of the signal
actuating device thus enabling the signal to be worked as required but that when
an engine or other vehicle is on the section in question or a derangement of the
apparatus takes place the electric current is short circuited and the signal is caused
to move to the danger position substantially as described.
Third. The method of arranging and locking the parts of the signal or parts of

page_text: the apparatus working the signal governing the section of line to be protected at
any convenient point between the signal lever in the signal cabin and the signal
itself, substantially as described with reference to Figures 1 to 5 of the accom-
panying drawings.
Fourth. The arrangement of parts by means of which the electrical current
having been brought into use for the purpose of doing its work is again cut off
thereby saving the battery current substantially as described, with reference to
Figures 2 and 3.
Fifth. The application of a screen or indicator O, in the neighbourhood of the
lever operating the signal substantially as described with reference to Figures 6
and 7.
Sixth. The constructions of apparatus for causing the automatic control of
railway signals as shown on the drawings.
Dated this 22nd day of Anril 1892
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.