Improvements in Apparatus for Controlling Traffic on Railways on the Staff System.
Year: 1899

page_text: Date of Application, 12th May, 1899
Complete Specification Left, 6th Sept., 1899-Accepted, 7th Oct., 1899
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Controlling Traffic on Railways on
the Staff System.
I, CHARLES DANIEL THEOBALD, of Arkonam, in the North Arcot District, Madras
Presidency, Chief Telegraph Inspector, Madras Railway, do hereby declare the
nature of this invention to be as follows:-
This invention relates to apparatus for controlling traffic safely on single
and double lines of railway on the staff system, in which there is employed in
conjunction with the said apparatus a staff or authority" in the form of a key
as hereinafter described.
66
An apparatus constructed in accordance with this invention is illustrated
diagrammatically in the accompanying drawings in which,-
**
Figure 1 is a front elevation showing a polarized galvanometer G; keys or
authorities" K; a bell hammer, protected by a cover H; a bell or gong B;
fences FF; a slot or magazine M for receiving the keys; a check plate C, a dust
protector DC; a lock L; and a push button P, for transmitting code messages
to the other end of the section.
Figure 2 is a right hand side elevation showing a hinged door 1) for affording
access to the internal mechanism of the apparatus; a sliding door S D for the
same purpose; and the continuation of the slot M for the keys K. The dotted
lines m m m m indicate guard plates to prevent the turning over of the keys.
Figure 3 is a left hand side elevation showing a hinged trap door T D for
affording access to the back of the relay. The cover DC, secured by screws
is to allow of removing any accumulation of dust on the pivots of the internal
mechanism which on this side work in the plate forming the outer casing of
apparatus.
Figure 4 illustrates a suitable form of key or authority" with the names of
the block section stations engraved on the bosses or handles.
Figure 5 is a front elevation of a "train going" indicating appliance used in
connection with the lock block or train key apparatus for double line working.
Figure 6 is a sectional side elevation of the train going" indicator in which
are shewn the check plate C; the fences F; key slot M; bolt lock B L; indicat-
ing slide S and electric lock E L.
Figure 7 shows a wire loop with clip to facilitate exchange of keys at stations
where trains do not stop.
Figure 8 shows the inner mechanical and electrical arrangements with their
connections the outer cover of casing on the right being removed.
Figure 9 is a view of the bell coil and hammer, and of the astatic relay, as
seen from the rear end of the apparatus.
In these figures g m indicates the inducing magnet and ge the coils of the
polarized galvanometer.

page_text: A A are the coils, O the astatic tongue with contact springs a¹, a² and N the
armature with contact springs 61, 62 of the astatic relay.
6 is an electro-magnet for ringing the bell or gong B and for inductively
magnetising the astatic tongue 0 while the electro magnet itself is energized;
T is a six-pronged rotating tumbler operating in conjunction with a rocking
lever reversing switch R.
A lever E, with its roller f and spiral spring f¹ serve to control the rotating
tumbler T.
c is the shield of a safety switch V which has two contacts and g; 1, are
two contact plates joined across by a pin ; this is also a safety connection, as
will be explained later on. U is an electro magnet for actuating a locking
pawl u; is a spring connected to the line terminal and e is a spring connected
to the earth terminal. These two springs are fixed, insulated from each other,
on one arm of the rocking lever switch R, of which they are a continuation;
they make contact at points n and s or n¹ and as controlled by the rotating
tumbler T; Q is a line battery it also serves to energize the electro magnet U;
J is a local battery for energizing the bell coil b.
X are two terminals which are connected to the train going indicator when the
apparatus is used for working traffic over double lines of railway. When the
apparatus is used for single line working these two terminals X are joined across
by a strip of metal.
The dotted lines shew the electrical connections in the apparatus. The top
plate for the pivots of the parts E, R, T, u at this side is not shewn.
I shall now describe the method of working the apparatus and the function
which each part of it performs.
FOR WORKING TRAINS ON SINGLE LINE RAILWAY.
Each of the two block stations which I shall call Y and Z connected together
by a line wire and earth connection or return wire is provided with an apparatus
of the kind' shown, and a given equal number of keys are stowed away in the
slot or magazine M above the apparatus. When the operator at Y has a train
to start, he will ring up the operator at Z whose galvanometer needle at each
stroke of his bell will point to the white or "all clear" side of his dial, and on the
operator at Z replying, the same effects will be produced on the bell and galvano-
meter at Y. Both stations will now know that the section is clear and the
operator at Y will, by the code in use, ask the operator at Z for permission to
block the section and withdraw a key in order to dispatch a train from Y. If
the operator at Z be prepared to accept the train from station Y he will give Y
the permission, by the code in use, and prolong the last beat of the series. This
will cause the now magnetized tongue of the astatic relay to bring the two
springs a¹ and a² into contact in the apparatus at Y. The operator at this latter
station will now slip a key K down from the slot or magazine M. The shaft
of the key K, in getting into its seating at the bottom end of the slot moves
away the shield c of the switch V, thus cutting off the negative pole of the line
battery Q from the plunger contact d and joining that pole so as to complete the
circuit of the coil U through the contact g and the relay springs a¹ and a
coil U attracts its armature which lifts the locking pawl u clear of one of the
prongs or teeth on the periphery of the rotating tumbler T which engaged it.
The operator at Y, grasping the handles or bosses of the key K between the
thumb and fore-finger of each hand can now move the key K round so as to
engage its tongue with a tooth of the rotating tumbler T as shewn at K¹.
moving the key further round into the position shown at K³, the tumbler T will
be rotated and the pin 2 will spring into the position of the tooth which is
between 2 and 3, pushing down one arm of the rocking lever R and raising the
other arm;
thus moving the line and earth springs e and from n and s to n
and s. This, as will be seen, causes an instant reversal of the line and earth
connections. The operator at Y can now withdraw the key through a lateral
:
In

page_text: passage leading from the slot M to the front of the apparatus some little distance
above the bottom end of the slot, as shown at K³. The switch V is now pulled
by the spring against the normal contact d. If the operator at either station
now worked his plunger P he would move the galvanometer needle at the other
station to the red side of the dial and the relay tongue O away from the contact
springs a a²; consequently no second key can be withdrawn from either apparatus.
The key cannot be withdrawn directly through the lateral passage at K³ because
the guard plate m m prevents the tongue on the key turning over at that point.
An opening in the guard plate allows the tongue (when the key is in its seating)
to be tilted over into the position K and then moved round into the position K²
as above described. From the latter position alone can the key be removed
through the passage at K. In returning the key it is introduced tongue foremost
as shown at K³ into the apparatus. It is then moved down into the position K²
and then moved round into the position K¹. This last movement turns the tumbler
back one tooth and in doing so at either station, both apparatus are restored to
their normal condition.
The armature N by pressing together the contact springs 61, 63, always sends a
current of the same polarity through the bell coil b, which induces magnetism
of the same polarity in the tongue O, each time a signal is received by one
cleared."
station from the other, whether the section is blocked or
The roller of the controlling lever E, under the influence of the powerful
spiral spring f¹, moves the rotating tumbler T into such a position as to cause
one of the teeth of the tumbler to engage with the locking pawl u whenever a
key is withdrawn from or returned into the apparatus. The line and earth
springs and e on the rocking lever reversing switch R are therefore forced into
contact with either the contacts n and s or n¹ and s¹, so that any accidental or
careless manipulation of the key will not cause disconnection of the circuit, other
than the momentary disconnection caused by the tumbler pins t¹, t³, or t³ in rock-
ing the lever switch R.
Should the spiral spring fl of the controlling lever E break, the rocking
lever R will, by the force of the spring i, control the position of the rotating
tumbler by pressing against any two of the pins t¹, ta, t, so that if a key is with-
drawn from, or returned into, the apparatus, the line and earth springs l, e, will
still make contact with the lower contacts n and s. In order to prevent any wrong
manipulation occuring from such derangement I connect the line to contact
plate and from another contact plate I continue the line connection to the
spring on the reversing switch R. The connection between the contact plates l¹
and is completed through the pin as long as the spring f¹ is in tension but
if the latter breaks, the pin 3 drops, the circuit is broken and no key can be
withdrawn until the broken spring f¹ has been replaced by an authorised person,
who alone can gain access to the interior of the apparatus.
The object of the safety switch V is two fold-firstly to prevent the possibility
of the operator at Y, after just releasing the engaged tooth of the tumbler T
from pawl and before actually breaking contacts at the points n and s or n¹
and of giving permission to Z to withdraw a key there at the same time, or
vice versa and secondly to prevent the energizing, other conditions being favour-
able, of coil U, when a key is not required to be withdrawn. The key with-
drawn at station Y has to be taken to station Z and returned into the apparatus
there, or brought back to station Y and returned into the apparatus at that
" cleared."
station before the section can be
The galvanometer G not only indicates when the section is "blocked" or
"clear" but it also enables the operator at one station giving the permission
to the other station to know, by a momentary jerk of his own needle when that
other station has liberated a key for withdrawal.
The keys K are made in varying sizes as to length, and the fences F F and
check plate C (Figures 1, 2, 3) are so constructed as to accommodate correspond-

page_text: ing keys and prevent the possibility of accidentally, or otherwise, returning a
key into the wrong apparatus.
For working trains on double lines of railway the "train going". indicator
appliance (Figures 5 and 6) is connected to the two terminals X Figure 8.
As trains on double lines move in opposite directions on separate lines, any
station on a block section of such line is concerned only as to trains going from
that station to the next.
""
"
on line"
Assuming now that the operator at Y has to dispatch a train to Z. He will
with permission from % withdraw a key K from his single line apparatus, intro-
duce it into slot M, Figure 6, and, by engaging the tongue of this key. with the
projecting piece on the front of the slide S, lift the slide upwards. When the
slide has been raised to the end of its upward travel it is held in that position
by an inclined tooth on its back engaging with the inclined tooth on the armature
of the electric lock E L, and also by the bolt lock B L shooting into the bolt
hole. The words "cleared line now become invisible and the words
are exhibited through the window.
The key K has now to be returned by the operator at Y into his apparatus. On
the arrival of the train at %, the operator at Z will inform the operator at Y, by
the code in use, and hold down his plunger. The operator at Y will immediately
slip the key K down into its seating (so as to actuate the switch V Figure 8) and
thereby release the electric lock E L and he will then pull out the bolt lock BL
which will allow the slide S to drop into its normal position. The operator at Z
can by similar manipulation send a train on to Y even while one is coming to
his own station from Y.
It sometimes happens that one line of rails is obstructed by an accident, and
that up and down traffic on the interrupted section has to be worked over one
line of rails. In such cases the "pilot guard" system is most usually installed
to work the traffic over the section-that is, a special man in uniform is authorized
to pilot every train passing over such interrupted section-and as there is
only one pilot its follows that only one train can be run either way at one time.
This-system, however, entails much delay by the necessary preliminary arrange-
ments in supplying the pilot guard and in the case of two or more trains moving
in one direction, the train which is due to go next must wait until the pilot has
arrived at the next station with the previous train and in the absence of a train
returning in the opposite direction the pilot has to get back by the "best means
at his command."
All these delays would be avoided in cases of obstruction by merely working
on the single line system-that is giving the key over to the driver of every train
passing into the section from either one end of it while the obstruction to one
line of rails exists.
The chief features of my invention are the following,
First. Its adaptability for working traffic over either single or double lines
of railway and vice versa when necessary.
Second. An astatic relay is employed to control the locking mechanism thereof.
Third. A galvanometer is provided to unerringly indicate whether the section
is "blocked" or "clear"; it cannot give a wrong indication either in consequence
of the effects of extraneous currents, or of forgetfulness on the part of the
operator.
.
Fourth. The manipulation of the apparatus is similar to that of an ordinary
large lock so that even an operator of limited experience cannot fail to lock (or
block") the section and obtain the authority for a train to proceed to the
66
next station..
Fifth. Only one appliance need be operated for communicating signals to the
next station, or to give that station permission to'lock (or "block") the section
and obtain the required authority.
Sixth. A rotating tumbler is employed in conjunction with a rocking lever
seversing switch so as to obviate the possibility of the operator, either through

page_text: carelessness or forgetfulness, leaving the section in a condition other than either
blocked"
"
or
cleared."
Dated this 11th day of May 1899
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London Chartered Patent Agents.
Improvements in Apparatus for Controlling Traffic on Railways on
the Staff System.
I, CHARLES DANIEL THEOBALD, of Arkonam, in the North Arcot District, Madras
Presidency, Chief Telegraph Inspector, Madras Railway, 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 relates to apparatus for controlling traffic on single and double
lines of railway on the staff system, in which there is employed in conjunction
with the said apparatus a staff or authority" in the form of a key as herein-
after described.
The advantages and objects to be realised by this invention are:-reduction to
a minimum of the number of the parts of the apparatus, simplicity in the mani-
pulation of the said parts, and economy in the space required for installing the
apparatus, thus lessening considerably the cost of manufacture and transport of
the same.
An apparatus constructed in accordance with this invention is illustrated
diagrammatically in the drawings left with my Provisional Specification,and to
which I now refer.
"
In those drawings, Figure 1 is a front elevation showing a polarized galvano-
meter G; keys or authorities" K; a bell hammer, protected by a cover H;
a bell or gong B; fences F F; a slot or magazine M for receiving the keys; a
check plate C; a dust protector DC; a lock L; and a push button P. for trans-
mitting code messages to the instrument at the other end of the section.
Figure 2 is a right hand side elevation showing a hinged door D) for affording
access to the internal mechanism of the apparatus; a sliding door S D for the
same purpose; and the continuation of the slot M for the keys K. The dotted
lines m m m m indicate guard plates to prevent the turning over of the keys.
Figure 3 is a left hand side elevation showing a hinged trap door T D for
affording access to the back of the relay. The cover D C, secured by screws
is to allow of removing any accumulation of dust on the pivots of the internal
mechanism which on this side work in the plate forming the outer casing of
the apparatus.
Figure 4 illustrates a suitable form of key or "authority" with the names of
the block section stations engraved on the bosses or handles.
Figure 5 is a front elevation of a "train going" indicating appliance used in
connection with the lock block or train key apparatus for double line working.
Figure 6 is a sectional side elevation of the train going" indicator in which
are shewn the check plate C; the fences F; key slot M; bolt lock B L; indicat-
ing slide S and electric lock E L.
'Figure 7 shows a wire loop with clip to facilitate exchange of keys at stations
where trains do not stop.
Figure 8 shows the inner mechanical and electrical arrangements with their
connections--the outer cover of casing on the right being removed.

page_text: Figure 9 is a view of the bell coil and hammer, and of the astatic relay N O, as
seen from the rear end of the apparatus.
In these figures gm indicates the inducing magnet, and ye the coils of the
polarized galvanometer.
A A are the coils, O the astatic tongue with contact springs a¹, a² and N the
armature with contact springs 61, 62 of the astatic relay.
b is an electro-magnet for ringing the bell or gong B and for inductively
magnetising the astatic tongue while the electro-magnet itself is energised;
T is a six-pronged rotating tumbler operating in conjunction with a rocking
lever reversing switch R.
A lever E with its roller f and spiral spring f¹ serve to control the rotating
tumbler T.
e is the shield of a safety switch V which has two contacts and g; 1, Pare
two contact plates joined across by a pin ; this is also a safety connection, as
will be explained later on. U is an electro magnet for actuating a locking
pawl u; 7 is a spring connected to the line terminal and e is a spring connected
to the earth terminal. These two springs are fixed, insulated from each other,
on one arm of the rocking lever switch R, of which they are a continuation;
they make contact at points n and s or n¹ and s¹ as controlled by the rotating
tumbler T Q is a line battery, it also serves to energise the electro magnet U;
J is a local battery for energising the bell coil b.
X are two terminals which are connected to the train going indicator when the
apparatus is used for working traffic over double lines of railway. When the
apparatus is used for single line working these two terminals X are joined across
by a strip of metal.
The dotted lines shew the electrical connections in the apparatus. The top
plate for the pivots of the parts E, R, T, at this side is not shown.
I shall now describe the method of working the apparatus and the function
which each part of it performs.
FOR WORKING TRAINS ON SINGLE LINE RAILWAY.
Each of the two block stations which I shall call Y and Z connected together
by a line wire and earth connection or return wire is provided with an apparatus
of the kind shown, and a given equal number of keys are stowed away in the
slot or magazine M above the apparatus. When the operator at Y has a train
to start, he will ring up the operator at Z whose galvanometer needle at each
stroke of his bell will point to the white or "all clear" side of his dial, and on the
operator at Z replying, the same effects will be produced on the bell and galvano-
meter at Y. Both stations will now know that the section is clear and the
operator at will, by the code in use, ask the operator at Z for permission to
block the section and withdraw a key in order to dispatch a train from Y. If
the operator at Z be prepared to accept the train from station Y he will give Y
the permission by the code in use by means of the push button P
and prolong the last beat of the series. This will cause the now
magnetized tongue of the astatic relay to bring the two springs al
and a into contact in the apparatus at Y. The operator at this latter
station will now slip a key K down from the slot or magazine M. The shaft
of the key K, in getting into its seating at the bottom end of the slot moves
away the shield c of the switch V, thus cutting off the negative pole of the line
battery from the plunger contact d and joining that pole so as to complete the
circuit of the coil U through the contact and the relay springs a¹ and a²-
coil U attracts its armature which lifts the locking pawl a clear of one of the
prongs or teeth on the periphery of the rotating tumbler T which engaged it.
The operator at Y, grasping the handles or bosses of the key K between the
thumb and forefinger of each hand can now move the key K round so as to
engage its tongue with a tooth of the rotating tumbler T as shewn at Ki. In
moving the key further round into the position shown at K2, the tumbler T will

page_text: be rotated and the pin 2 will spring into the position of the tooth which is
between t3 and t, pushing down one arm of the rocking lever R and raising the
other arm; thus moving the line and earth springs e and from n and s to ni
and . This, as will be seen, causes an instant reversal of the line and earth
connections. The operator at Y can now withdraw the key through a lateral
passage leading from the slot M to the front of the apparatus some little distance
above the bottom end of the slot, as shown at K³. The switch V is now pulled
by the springh against the normal contact d. If the operator at either station
now worked his plunger l' he would move the galvanometer needle at the other
station to the red side of the dial and the relay tongue 0 away from the contact
springs a¹ a²; consequently no second key can be withdrawn from either apparatus.
The key cannot be withdrawn directly through the lateral passage at K because
the guard plate m m prevents the tongue on the key turning over at that point.
An opening in the guard plate allows the tongue (when the key is in its seating)
to be tilted over into the position K' and then moved round into the position
as above described. From the latter position alone can the key be removed
through the passage at K³. In returning the key it is introduced tongue foremost
as shown at into the apparatus. It is then moved down into the position K²
and then moved round into the position K¹. This last movement turns the tumbler
back one tooth and in doing so at either station, both apparatus are restored to
their normal condition.
The armature N pressing together the contact springs 61, 62, always sends a
current of the same polarity through the bell coil b, which induces magnetism
of the same polarity in the tongue O, each time a signal is received by one
cleared."
station from the other, whether the section is blocked or
The roller of the controlling lever E, under the influence of the powerful
spiral spring f, moves the rotating tumbler T into such a position as to cause
one of the teeth of the tumbler to engage with the locking pawl u whenever a
key is withdrawn from or returned into the apparatus. The line and earth
springs and e on the rocking lever reversing switch R are therefore forced into
contact with either the contacts n and s or and s¹, so that any accidental or
careless manipulation of the key will not cause disconnection of the circuit, other
than the momentary disconnection caused by the tumbler pins t¹, 2 or 3 in rock-
ing the lever switch R.
Should the spiral spring f¹ of the controlling lever E break, the rocking
lever R will, by the force of its spring i, control the position of the rotating
tumbler by pressing against any two of the pins t, 2, 3, so that if a key is with-
drawn from, or returned into, the apparatus, the line and earth springs 1, e will
In order to prevent any wrong
still make contact with the lower contacts and s.
manipulation occuring, from such derangement I connect the line to contact
plate and from another contact plate I continue the line connection to the
spring on the reversing switch R. The connection between the contact plates
and is completed through the pin as long as the spring f is in tension but
if the latter breaks, the pin, drops, the circuit is broken and no key can be
withdrawn until the broken spring has been replaced by an authorised person,
who alone can give access to the interior of the apparatus.
The object of the safety switch V is two fold-firstly to prevent the possibility
of the operator at Y, after just releasing the engaged tooth of the tumbler T
from pawl u and before actually breaking contacts at the points n and s or n¹
O and s of giving permission to Z to withdraw a key there at the same time, or
vice versa and secondly to prevent the energizing, other conditions being favour-
able, of coil U, when a key is not required to be withdrawn. The key with-
drawn at station Y has to be taken to station Z and returned into the apparatus
there, or brought back to station Y and returned into the apparatus at that
station before the section can be "cleared.".
35
$
blocked'
or
The galvanometer G not only indicates when the section is
"clear
but it also enables the operator at one station giving the permission

page_text: to the other station to know, by a momentary jerk of his own needle when that
other station has liberated a key for withdrawal.
"The keys Kare made in varying sizes as to length and the fences F F and
check plate C (Figures 1, 2, 3) are so constructed as to accommodate correspond-
ing keys and prevent the possibility of accidentally, or otherwise, returning a
key into the wrong apparatus.
When a key has been released at a station for a train which does not stop,
the station master or the signalman must slip the key into the iron clip or pocket,
forming a part of the wire loop shown in Figure 7. This loop is picked up
by the driver passing his arm through it while the signalman holds it up or it
may be automatically picked up from a "gallows" on the side of the line by an
arrangement from the engine. In either case the driver takes possession of the
key for the section he is entering and places in the loop clip the key for the
section he has just cleared and drops them for the signalman to take possession
of the same.
For working trains on double lines of railway the "train going" indicator
appliance (Figures 5 and 6) is connected to the two terminals X Figure 8.
As trains on double lines move in opposite directions on separate lines, any
station on a block section of such line is concerned only as to trains going from
that station to the next.
Assuming now that the operator at Y has to dispatch a train to Z, he will
with permission from Z withdraw a key K from his single line apparatus, intro-
duce it into slot M, Figure 6, and, by engaging the tongue of this key with the
projecting piece on the front of the slide S, lift the slide upwards. "When the
slide has been raised to the end of its upward travel it is held in that position
by an inclined tooth on its back engaging with the inclined tooth on the armature
of the electric lock E L, and also by the bolt lock BL shooting into the bolt
hole. The words "cleared line" now become invisible and the words " on line'
are exhibited through the window.
The key K has now to be returned by the operator at Y into his apparatus. On
the arrival of the train at Z, the operator at Z will inform the operator at Y, by
the code in use, and hold down his plunger. The operator at Y will immediately
slip the key K down into its seating (so as to actuate the switch V Figure 8) and
thereby release the electric lock E L and he will then pull out the bolt lock B L
which will allow the slide S to drop into its normal position. The operator at Z
can by similar manipulation send a train on to Y even while one is coming to
his own station from Y.
It sometimes happens that one line of rails is obstructed by an accident, and
that up and down traffic on the interrupted section has to be worked over one
line of rails. In such cases the "pilot guard" system is most usually installed
to work the traffic over the section that is, a special man in uniform is authorized
to pilot every train passing over such interrupted section-and as there is
only one pilot it follows that only one train can be run either way at one time.
This system, however, entails much delay by the necessary preliminary arrange-
ments in supplying the pilot guard and in the case of two or more trains moving
in one direction, the train which is due to go next must wait until the pilot has
arrived at the next station with the previous train and in the absence of a train
returning in the opposite direction the pilot has to get back by the "best means
at his command."
All these delays would be avoided in cases of obstruction by merely working
on the single line system-that is giving the key over to the driver of every train
passing into the section from either one end of it while the obstruction to one
line of rails exists.
The chief features of my invention are the following,-
First. Its adaptability for working traffic over either single or double lines
of railway and vice versa when necessary.
Second. An astatic relay is employed to control the locking mechanism thereof.

page_text: Third. A galvanometer is provided to unerringly indicate whether the section
s"blocked" or clear"; it cannot give a wrong indication either in consequence
of the effects of extraneous currents, or of forgetfulness on the part of the
operator.
Fourth. The manipulation of the apparatus is similar to that of an ordinary
large lock so that even an operator of limited experience cannot fail to lock (or
block") the section and obtain the "authority" for a train to proceed to the
next station.
66
Fifth. Only one appliance need be operated for communicating signals to the
next station, or to give that station permission to lock (or "block") the section
and obtain the required "authority.'
Sixth. A rotating tumbler is employed in conjunction with a rocking lever
reversing switch so as to obviate the possibility of the operator, either through
carelessness or forgetfulness, leaving the section in a condition other than either
"blocked" or
cleared."
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. For controlling traffic on single lines of railway on the staff system, the
combination of parts constituting the improved section locking or blocking
apparatus constructed, arranged and operating, substantially as hereinbefore
described and shown.
2. In apparatus for controlling traffic on single lines of railway on the staff
system, an astatic relay for controlling the locking mechanism arranged and
operating, substantially as described.
3. In apparatus for controlling traffic on single lines of railway on the staff
system, a galvanometer for indicating whether the section is "blocked" or
cleared," arranged and operating substantially as described.
4. In apparatus for controlling traffic on single lines of railway on the staff
system the combination of a rotating tumbler, such as T, with a rocking lever
reversing switch such as R, for preventing disconnection of the line circuit,
arranged and operating substantially as described.
5. For controlling traffic on double lines of railway by means of apparatus
such as referred to in the preceding claims, the use in combination with such
apparatus of a "train going” indicating appliance, constructed, arranged and
operating substantially as described and more particularly with reference to
Figures 5 and 6.
this fth day of September 1899.
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London.
Chartered Patent Agents.