An Improved Safety Block System for Railway Signalling.
Year: 1892

page_text: Date of Application, 14th Oct., 1892-Accepted, 10th Dec., 1892
COMPLETE SPECIFICATION.
An Improved Safety Block System for Railway Signalling.
We, WILLIAM ROBERT SYKES, Junior, of 43 Kent House Road, Beckenham,
in the County of Kent, Telegraph Engineer, and JOHN PATRICK O'DONNELL
of 2 Great George Street, Westminster, in the County of Middlesex, Civil
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 :-
Our invention consists in an improved method of interlocking the outside visual
signals with the block instruments.
With the existing known instruments at the present time the interlocking of the
block instruments and the outside signals is effected by means of the levers in the
signal box which operate the outside signals.
Our invention consists in avoiding any addition or alteration to the existing
operating levers in a signal box and further would leave any special form of inter-
locking apparatus intact.
We arrange that the interlocking takes place by means of special apparatus
fixed in the upright rod on the signal post intermediate between the balance lever
and the arm.
In connection with our apparatus we arrange a special instrument suitable for the
altered circumstances.
Briefly, we arrange that, supposing two sections A and B, B is free to accept a
train from A under the normal condition. B plunges through the special instrument,
which we will hereinafter describe, and through the apparatus fixed upon the signal
post he places certain apparatus so that the action of working the lever operating
the starting signal at section A effects the lowering of the said signal.
Assuming that B gives his permission A operates his starting signal lever, the
said starting signal being deflected; a treadle or rail contact is arranged a suitable
distance in advance of the starting signal and operates that when a train has
arrived and deflected the said treadle or rail contact, the starting signal in its rear
is replaced to the "danger" attitude.
It is immaterial whether the signalman replaces his starting signal lever or not,
for he cannot lower the starting signal a second time until permission is given by B.
The train having left A has approached B and drawn up under the protection
of B's starting signal; even then B is not in a position to release the starting
signal at A. It is only when the starting signal at B has been lowered by the
operation of B's starting signal lever. The train can then proceed over the treadle
in advance, operate the said treadle, and replace B's starting signal to danger
and through it, B's starting signal being at danger," a current is taken to the
instrument at B, which, if he wishes, enables him to plunge and release A's starting
signal, so that he can accept a second train from A.
tr
"
It will thus be seen that whereas at the present time outside signals are controlled
through the movements of their operating levers, in our invention we practically
disregard the levers which operate the said signals, and interlock the arms
themselves.
It is understood that in the event of B accepting a train from A and B wishing
to cancel the signal previously given, provided the train has not started from A
and depressed the treadle, B has power to reverse his operation and replace A's
starting signal to "danger."
It will be readily understood that if trains are required to be brought in closer
1 '

page_text: connection, that is to say, one at the starting signal in the section and one at the
stop signal in the same section, that to carry out our invention a second treadle is
needed a suitable distance ahead of the stop signal and one of our apparati fixed in
the upright rod, intermediate between the balance lever and the arm of the stop
signal in that section. Generally, trains can be drawn up at every signal, other
than a distant signal, provided our apparatus is fixed in the upright rods of these
signals and sufficient treadles are placed in advance of the said signals.
In order that our invention may be better understood and more readily carried
into effect we will proceed to describe the drawings hereunto annexed. The same
numbers refer to the same parts or substitutes therefor in the several figures.
Figure 1 illustrates two sections, A and B, on an ordinary line of railway.
In this figure, 1 is the stop signal at A, 2 the starting signal at A, 3 the stop
signal at B and 4 the starting signal at B. is the treadle the required distance
in advance of the starting signal at A, and 6 is the treadle in advance of the
starting signal at B.
Figure 2 illustrates the instrument at A for forwarding instructions for a train.
The usual system for asking instructions for a train by means of a bell is used with
our invention. The existing system of three wires we also employ, one for the bell.
and one each for up and down lines.
Figure 2 illustrates the instrument containing an electro-magnet, armature, and
arm indicator. In this figure. also the lever in the locking frame operating the
starting signal is illustrated. The starting signal itself is also illustrated, showing
the apparatus in the upright rod.
Figure 3 illustrates the receiving instrument at B. 7 is the dial of the instru
ment indicating to the signalınan at A whether in operating his lever the starting
sigual arm will be deflected or not. In the interior of 7 the electro-maguet 8 is
fixed and the armature 9 and contact 10. 11 is the mechanical lever in the inter-
locking apparatus operating the starting signal 2 Figure 1. Behind the starting
signal lever is arranged what we call a contact maker, comprising two springs 12
and 13, joined together when the catch-handle is raised. When the drop box 14
of the catch-handle is raised it allows the two springs 12 and 13 to come together.
15 is the battery. At the right hand of the battery the wire goes to earth. The
wire from the contact 10 leads to the apparatus fixed in the upright rod on the post
of the starting signal 2. 16 illustrates the position in the upright rod, of our
apparatus on the post. 17 is the line wire from the instrument at B, being
intermediately intercepted by the treadle fixed in advance of the starting signal
at A. 18 is the instrument at B, indicating whether the line is blocked or not.
"
When the current arrives at 22 it has two paths, one only passing through the
arm indicator to a spring 23 arranged on the armature; the other path passes
through the electro-magnet 25 to another spring 26 arranged on the same
armature 27. 28 is a plunger, 29 is a lever at the back of the plunger. The
lever 30 operates the armature 31. 32 is a click held up normally by the
armature 33. The armature 33 is centred at 34. 35 is the electro-magnet
operated by the treadle. 36 is the wire from the armature to the treadle 37. The
treadle 37 is a "making contact treadle. The wire 38 is to the earth. 39 is the
wire leading through battery 40 to earth. 41 is a wire running from the spring 26
of the armature 27. 42 is a spring. 43 is a spring. 44 is the contact connecting
one spring with the other. 45 is the switch which consists of a steel spindle one
end is passed through front of instrument case and provided with a handle; on the
other end, a metal segment 45 is fixed upon which the spring 42 rests. 46 is the
contact through the resistance to earth. 47 is an insulating piece on spring 42.
48 is the contact in the wire connecting with spring 23 in connection with
contact 49.
The working of our invention is as follows:-Referring again to Figure 1, A is
ready to send a train to B, and for this purpose must get B's permission;
Bplunges, in Figure 3, 28; 28 pushes forward lever 29, 29 through its projection 30

page_text: pushes forward armature 31, making contact with the electro-magnet 25, this also
displaces click 32 and the armature 33 falls, the thickened portion falling in front
of the click 32 and on top of the lever 29; by this action the click 32 cannot be
moved forward and the lever 29 cannot be moved backward. The armature in
connection with the electro-magnet 25 is in contact at its lower portion 27 with the
contact pieces 49 and 50, with the result that the current of battery 20. travels to
the indicator 18 and to the electro-magnet 25. This has resulted in the arm of
the indicator instrument at B being lowered to the "safety" attitude, and the
current passing from the magnet 25 along the line through the contact 48 to the
lower spring 43 and along the line wire through the treadle 51 at A. and into
the instrument 7, deflecting the arm to the safety attitude. It also passes through
the electro-magnet 8 to earth at 52. Upon the withdrawal of the hand from the
plunger the lever 29 has a movement towards the plunger and the thickened
portion 33 falls between the lever 29 and the click 32 in its moved position. By
this it will be observed that both the click and the lever and, indirectly, the plunger,
are locked in their positions.
B further in plunging has left a current on so that the armature 9 is moved up
to the electro-magnet 8 in contact with the contact piece 10; by this the current.
is on at the contact piece 12, so that A. in operating his starting signal lever, moving
up the drop box allows springs 12 and 13 to come in contact. The signalman is
now free to operate the lever and deflect the signal.
It is understood that the starting signal lever is normally free, but under the
conditions named when B has plunged if the starting signal lever is operated the
current passes through wire 53, through the armature 9, making contact with
the contact piece 10, and so goes to the apparatus fixed upon the post, 16, and
through this to earth. This action allows when the starting signal lever itself is
operated that the arm be deflected. Upon the deflection of the starting signal
and the train proceeding towards B, it operates the treadle 51, breaks the line
current, and replaces the arm to "danger," allowing the armature 9 to drop from
its contact with magnet 8, putting the arm to "dauger" in the instrument at A
and also in the instrument at B and drops the armature 31 at B. That action
breaks the contacts 49 and 50, in fact, breaks all contacts previously made by the
plunging at B.
In order to release B's plunger and enable him to take a second train from A,
the train itself must have passed over the treadle 6 at B in advance of B's starting
sigual 4. He makes the contact and raises the armature 33 and allows the click 32
to fall by gravitation to its normal position and also allows lever 29 to be plunged
by B for a second operation.
Figure 4 illustrates one among the various modifications that may be devised of
our apparatus fixed in the upright rod on the signal post intermediate between the
balance lever and the arm.
In this figure 54 is the upright rod from the top of our apparatus to the arm;
55 is a lever centred at 56, having its end formed as a tooth or catch 57 and its
end 58 connected to a link 59. 60 is an electro-magnet through which the link 59
passes to its armature 61. The spring 62 is connected to a fixed spot on the plate
and to the end of the said link 59. 63 is a lever its upper end 64 arranged for
connection with the end 57 of the lever 55 and its lower end 65 carries a roller 66;
the said lever is centred at 67. The lower portion of the upright rod 68 is from
the balance lever normally to the under side of the roller 66. The upper part
of the upright rod 68 is slightly bevelled to ensure the thrusting aside of the lever
when the current is withdrawn. 69 is the wire passing from the magnet 60 to the
contact 10 Figure 2. 70 is the wire passing from the magnet to earth.
The figure as shown illustrates our apparatus in the condition that the
signalman at B has given permission for the deflection of the arm, and the lever 63
is in gear with the click 55 at its end 57. In the normal condition of our apparatus
such connection of 57 and 64 would not be made so that if the man at A were

page_text: to operate his starting signal lever the upright rod 68 would thrust aside the
roller 66 and although an upward movement of the lower portion of the upright
rod 68 would take place the arm would not be deflected, but in the condition as
illustrated when the current from B indicating permission, has been sent, the
current goes through the contact to the back of the lever and from thence to the
magnet 60 to earth; by this means the armature 61 is held up to the electro-
magnet 60 and the lever 55 held down making connection with the lever 63,
locking it in position. If the balance lever is now operated by the operating
lever in the signal box the whole apparatus is moved upward and the arm
deflected.
It is obvious that although we have hereinbefore described the action of B
plunging through the treadle to the instrument, from the instrument to the lever,
and from the lever to the apparatus on the signal post, yet if desirable B may
plunge and go direct to the apparatus on the signal post without going to the
instrument in the signal box, and if desirable indication may be given of the
condition of the signal in A signal box. Although this latter is a simpler method
yet we have described it in detail in the manner first described in consequence of
its requiring less consumption of battery power.
It will be understood in our system that we have no need for cancelling signals,
as, assuming that B has plunged and given permission to A and then B wishes
that A should not act on such permission, he could suspend the permission
previously given by operating his switch, and when he wishes that A should act
upon the instructions previously given he simply reverses the switch and the
previous plunging is operative for A to act upon.
We have not considered it necessary or desirable to bind ourselves to any
particular form of treadle as it must be understood that our invention is applicable
with any form.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is :-
1. In railway signalling apparatus, arrangements whereby the section in advance
controls the arm of the sectional signal in the rear instead of as hitherto controlling
the lever operating such signal, substantially as herein described and as illustrated
in the accompanying drawings.
2. In railway signalling apparatus, arrangements by which a treadle fixed at any
desirable spot, upon its operation by a train, replaces the arm in the rear in con-
nection therewith to the "danger" attitude, substantially as described and as
illustrated in the accompanying drawings.
3. In block instruments for railway signalling apparatus, arrangements whereby
the operation of the switch suspends the authority previously given by operating
the plunger of the said instrument, substantially as described and as illustrated
in the accompanying drawings.
4. In block instruments for railway signalling purposes, arrangements whereby
when the signal has been suspended by the movement of the switch, the reversal of
the switch to its normal position makes operative the sanction previously given by
plunging, substantially as described and as illustrated in the accompanying
drawings.
5. In railway signalling, apparatus fixed intermediate between the balance lever
and the arm whereby the arm cannot be deflected unless sanction has been received
from the cabin in advance thereby allowing the operating lever to deflect the said
arm, or making the operation direct to the apparatus on the post, substantially as
described and as illustrated in the accompanying drawings.
6. In railway signalling, apparatus fixed upon the signal post by which after the
signal arm being once deflected it may be replaced by either its actuating lever, or.
by the treadle fixed in advance, or by the signalman in advance operating his

page_text: switch and so breaking the line current, substantially as described and as illustrated
in the accompanying drawings.
7. In railway signalling, apparatus fixed in the upright rod on the sigual post
intermediate between the balance lever and the arm, substantially as described and
as illustrated in the accompanying drawings.
Dated this 14th day of October 1892.
JOHN P. O'DONNELL,
2, Great George Street, Westminster, London, S.W.,
Agent for the said Applicants.