Improvements in Interlocking Levers in Railway Point and Signal Apparatus.
Year: 1890

page_text: Date of Application, 15th Nov., 1890
Complete Specification Left, 14th Aug., 1891-Accepted, 3rd Oct., 1891
TROYIDIUNAD DI MUIFICATION.
Improvements in Interlocking Levers in Railway Point and Signal
Apparatus.
We, JOHN PATRICK O'DONNELL of 2 Great George Street Westminster in the
County of Middlesex, Civil Engineer, and WILLIAM SMITH of 8 Geneva Road
Brixton in the County of Surrey, Engineer, do hereby declare the nature of this
invention to be as follows:-
Our invention has reference to further and more definite improvements in the
action of interlocking signals and points of railways.
Our improvements refer primarily to that class of interlocking known as the
tappet or plunger kind.
As is known, with this class of interlocking a tappet is provided to each working
lever, and locks are mounted on cross slides which work in and out of notches cut in
the said tappets.
Our improvements refer to the prevention of accidents of a nature similar to that
which occurred on the Great Western Railway on Tuesday the 11th of November
1890, in which a train was shunted from say the down line through the cross over
road on to the up line and there forgotten. The up home signal was lowered and a
collision occurred.
With our invention, assuming that all the levers are in their normal condition,
the necessary safety is given immediately the cross over road is worked over so that
the movement has taken place from the down line to the up, both the down and up
home signals are locked at danger and are not even released although the lever
working the crossing points is replaced normal. Before the up home signal is free
to be moved over the crossing points must be worked again and the down starting,
signal given for the train to go through the crossing away to the next section, or
the up starting signal must be given for the train to depart to the next section on
the up line.
It will be readily understood that our object is to absolutely dispose of the
train before a second train can be received into the same section on the same
line. If the train is standing on the down line then that train must be disposed of.
or put into the next section by the deflection of the starting signal before a second
train can be received into the same section on the down line. Where sidings are'
provided and it is not intended that trains should depart out of the section then the,
siding points must be pulled over and the signal given for the train to go into the
siding and clear of the trap points before the home signal referring to the line upon
which the train is already standing is free to be lowered.
:―
We propose to carry out our invention briefly as follows:-
For the purposes of illustration we will suppose that the train being on the down
line has to be shunted through the cross over road on to the up line to allow of:
another train to pass down it has to be shunted back through the cross over road on
to the down line and proceed to the next section. Further for the purposes of
explanation we will assume that the lever working the cross
over road is
numbered 4, the lever working the down starting signal numbered 8, the lever
working the down home signal numbered 9, the lever working the up home signal
numbered 2, and the lever working the up starting signal numbered 3. Lever 4 is
worked over making the crossing right for a shunt movement from the down to the
p line. The tappet attached to lever 4 when it is worked over places a square
ock into a square notch on the tappet attached to lever 2, lever 2 working the up
home signal; it also places a square lock into a square notch on the tappet attached
o lever 9 working the down home signal. It will thus be seen that when lever 4 is
PQ77

page_text: given working the cross over road, both the home signals are locked and no matter
how many times 4 is worked levers 2 and 9 the home signals are locked; they can
only be released by pulling over the starting signal 8, which has a tappet attached
to it and a notch of a suitable shape provided in the said tappet. When lever 4 is
pulled over in the action of placing the square lock into the square notch in the
tappet attached to lever 9 it also places a lock of a bevel shape into the tappet
attached to lever 8 to the extent that lever 9 cannot be freed again until lever 8 is
worked, by which action the tappet attached to lever 8 takes out the square lock
from the square notch in the tappet attached to lever 9 allowing the down home
signal to be pulled a second time.
It is obvious that our invention may be extended to any extent where there are
sidings provided at signalling sections, the object we arrive at being that when the
shunting movement takes place the train has to be disposed of clear of the main
lines of that section before the fouling home signal can be given a second time or
even a first time, in certain circumstances.
Dated this 15th dev of November 1800
JOHN P. O'DONNELL,
2, Great George Street, Westminster, London, S.W.,
Agent for the said Applicants.
COMPLETE SPECIFICATION.
Improvements in Interlocking Levers in Railway Point and Signal
Apparatus.
We, JOHN PATRICK O'DONNELL of 2 Great George Street, Westminster in
the County of Middlesex Civil Engineer, and WILLIAM SMITH of 8 Geneva Road,
Brixton in the County of Surrey, 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 has reference to further and more definite improvements in the
action of interlocking signals and points of railways.
Our improvements refer primarily to that class of interlocking known as the
tappet or plunger kind.
As is known with this class of interlocking a tappet is provided to each working
lever and locks are mounted on cross slides which work in and out of notches in the
said tappets.
Our improvements refer to the prevention of accidents of a nature similar to that
which occurred on the Great Western Railway on Tuesday the 11th of November
1890, in which a train was shunted from say the down line through the cross-over
road on to the up line and there forgotten. The up home signal was lowered and a
collision occurred.
With our invention, assuming that all the levers are in their normal condition,
the necessary safety is given immediately the cross-over road is worked over so
that the movement has taken place from the down line to the up, both the down
and up home signals are locked at danger and are not even released although the
lever working the crossing points is replaced normal.
Before the up home signal is free to be inoved over the crossing points must be
worked again and the down starting signal given for the train to go through the
crossing away to the next section, or the up starting signal must be given for
the train to depart to the next section on the up line.
It will be readily understood that our object is to absolutely dispose of the train
before a second train can be received into the same section on the same pair of
metals. If the train is standing on the down line then that train must be disposed
of or put into the next section by the deflection of the starting signal before a
second train can be received into the same section on the down line. Where
J

page_text: sidings are provided and it is not intended that trains should depart out of the
section then the siding points must be pulled over and the signal given for the
train to go into the siding and clear of the trap points before the home signal
referring to the line upon which the train is already standing is free to be
lowered.
In order that our invention may be more readily understood and carried into
effect we will proceed to describe the drawing hereunto annexed.
Figure 1 illustrates a plan of a double line station with a crossing added. The
letters referring to the points and signals correspond with the letters in Figures 2
and 3 which are supposed to operate the tappets which are connected to the said
levers.
It is obvious that in describing the working of the lever and the method of its
interlocking with reference to a particular number that the tappets attached to the
levers in Figures 2 and 3 are intended to illustrate the means by which the said
lever is interlocked.
In reference to this figure, 1 and 10 are the usual distant signals, and 2 and 9
are the stop signals, with which the invention is more immediately concerned.
Numbers 3 and 8 are the starting signals; 4 is the lever for operating the cross-
over road; 5 is the lever for operating the siding points from the up main back
into the siding, and 6 and 7 are the in and out discs to the said siding.
Figure 2 represents a plan of a locking trough with the levers in section and the
tappets projecting through the troughs illustrating the method by which the said
tappets are interlocked and through them the levers, by means of notches cut in
the said tappets into which engage locks attached to slide irons operated by
conflicting levers.
Numbers 1 to 10 represent the levers in section corresponding with the numbers
in Figure 1. In the channel marked A only ordinary interlocking is provided and
therefore reference need not be made to it in the Specification for the purposes of
illustrating the particular invention in reference to the cross-over road and the
home and starting signals. The tappets throughout are marked 1ª, 2ª, 3", etc.
In the locking bar or trough marked B is arranged the locking which forms the
subject of our invention.
In tappet 2 is provided a square notch 2b; in tappet 3ª an ordinary notch 3b;
in tappet 4ª an ordinary notch 4"; in tappet 8ª an ordinary notch 8, and in
tappet 9 a square notch 9.
Working in the channel, engaging with the notches according to the levers that
are operated are locks 2º, 3c, 4°, 8 and 9°.
Figure 3 illustrates the interlocking and details shown in Figure 2 but showing
lever 4 which operates the cross-over road in its worked position.
The same numbers and letters refer to the same parts as in Figure 2.
A brief description of our invention is as follows:-Referring again to the
forepart of our Specification it is assumed that a train, referring to Figure 1, has
arrived on the down line, signal 2 has been lowered and it has proceeded beyond
the starting signal 3 ready to shunt through the crossing 4 on to the up line to allow
another train to pass on the down. After the crossing 4 has been operated and
the train has gone through on to the up road, before, and it is obvious after, the
crossing has been replaced upon referring to Figure 3 it will be observed that the
tappet connected to lever 4 has worked through its notch 4 the lock 4° and by that
means operated the lock 2° into the notch 25 attached to lever 2, the lock 3° into
the notch 3 attached to lever 3, the lock 8° into the notch 8" attached to lever 8,
and the lock 9° into the notch 9" attached to lever 9.
It is obvious, referring to this condition of interlocking, that levers 2 and 9 are
interlocked and cannot of their own accord be made free again.
Again referring to Figure 1 it will be seen that as these levers (2 and 9) work
the stop signals the said stop signals are prevented from being operated until
another movement has taken place. Lever 4 may be replaced and thereby the
crossing put normal but still the locking prevents levers 2 and 9 from being

page_text: operated. If it is desirable that a second train he received from the section in the
rear on the down line to proceed through the station, to get the stop signal 2 the
starting signal 3 must be operated and upon reference to Figure 3 it will be observed
that the action of pulling over lever 3 operates tappet 3 and the notch 3 thrusts
out the lock 3 and as the square lock 2 is attached to the same slide as the lock 3°
the action of thrusting out the lock 3° also thrusts out the lock 2° thereby freeing
the tappet 2 and allowing lever 2 to be operated and the starting signal to be
deflected for the train to proceed.
It is obvious with further reference to Figure 3 that the same action in regard
to releasing the stop signal 9 would take place if the starting signal 8 were
operated as the square lock would be moved out of the square notch attached to
lever 9.
Again as previously referred to, assuming that the train had only been placed
on to the up line for temporary convenience to clear the down it may be shunted
through the crossing and the working of lever 3 would release both the up and
down stop signals.
Although discs have been shown at the ends of the cross-over road no levers
have been provided or illustrated on the drawings for working them as our
invention is quite independent of whether discs are provided or not. It is under-
stood that if discs are provided that it can be and should be made that in addition
to the cross-over road locking the stop signals the action of the disc being lowered
could also co-operate and the tappet attached to the lever working the disc signal
can be made to be forced to be worked before the stop signal referring to the line
from which the shunt is taking place can be operated. In that case not only
would the road be made right for the movement but also a definite signal given
for that movement and the said signal would have to be replaced before the stop
signal referring to the particular fine was free to be lowered. This movement of
course is in addition to the further movements of other starting signals being
operated as previously described.
In reference to movements into sidings a similar arrangement is applicable, as,
assuming a movement on the down line and it is to be shunted into the siding,
immediately the starting signal has been lowered an addition of ordinary con-
struction can be provided for making the home signal lock itself on its return
stroke only in the normal position and cannot be released until either the starting
signal has been lowered as previously described or the siding points 5 operated and
the disc 7 given for the train to proceed into the siding. Furthermore the said
addition of a lock can be arranged that the stop signal itself cannot be lowered a
second time, that is to say it locks itself in its return motion in its first movement
and cannot be released a second time until the crossing points have been operated
and the disc given, the arrangement being that assuming a train has arrived it
must either do one of three things, go forward to the next section by the starting
signal 3, shunt through the cross-over road with lever 4, or go into the siding by
lever 5 against all of which our arrangements are provided, the invention being
that it cannot be left on either of the roads and there forgotten, otherwise of course
the stop signal is locked.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we wish it to be
distinctly understood that we are aware of the Specification of Letters Patent
granted to the said John Patrick O'Donnell, No. 2911 dated March 1st 1886, and
of the Specification of Letters Patent granted to the said John Patrick O'Donnell
dated 13th June 1887 No. 8486, and we make no claim to anything described or
claimed therein, but what we do claim is :-
1. In railway signalling apparatus providing in the interlocking apparatus
tappets and locks operating in such a manner that when the movement of the
fouling point lever takes place the home signals referring to the fouled lines are
locked and are held locked notwithstanding the replacing of the point lever, the

page_text: said stop signal levers being only released by a prearranged movement of any
signal lever or other point lever which would place the conflicting vehicles acting
in obedience to such movement clear of the lines to which the stop signals refer,
substantially as herein described and as illustrated on the accompanying drawing,
2. In railway signalling apparatus, interlocking by means of tappets and locks
by which a stop signal cannot be operated a second time, that is to say that it
locks itself on its return stroke, and is held locked until a prearranged movement
has taken place, substantially as herein described.
Dated this 14th day of August 1891.
JOHN P. O'DONNELL,
2, Great George Street, Westminster, London, S. W.,
Agent for the said Applicants.