Improvements in Block Signalling Apparatus and Interlocking same with Outdoor Signals.
Year: 1892

page_text: Date of Application, 2nd Dec., 1892
Complete Specification Left, 17th Aug., 1893-Accepted, 30th Sept., 1893
PROVISIONAL SPECIFICATION.
Improvements in Block Signalling Apparatus and Interlocking same
with Outdoor Signals.
I FREDERICK THOMAS HOLLINS of Saltley House Forest Drive Leytonstone,
Essex, Telegraph Engineer to the Great Eastern Railway Company do hereby
declare the nature of this invention to be as follows:-
The object of this invention is to so interlock the block instrument for the section
in the rear with the lever working the outdoor signal controlling the section in
advance that when once a train has been accepted from the station in the rear
another train cannot be accepted on the block instrument again until the signal
lever at the home station controlling the section in advance has been actuated so as
to lower the signal and is put back to danger behind the train on its arrival and in
some cases to so arrange that the key or commutator used for sending the
"line clear" current cannot be used again to send the "line clear" current or
current to indicate "line clear" to the station in the rear until the train itself has
passed out of the section into the section in advance and the signal is to danger
behind it and further in some cases I arrange so that the starting signal or other
signal controlling the section in advance cannot be lowered for a train to start or
enter the section in advance without the concurrence and permission of the signal-
man at the signal box or station in advance. This invention is applicable to all
kinds of block instruments either single wire block for double lines or the ordinary
two or three wire block and also to the needle form or to the disc form of block
instrument.
In the simplest form and especially applicable to Tyers single wire block instru-
ments for double lines where a plunger is used to transmit the indication of
"line blocked" to the station in the rear and another plunger usually a white
plunger in the same instrument to transmit the. "line clear" indication to the
station in the rear and where a commutator is used inside the said instrument and
which said commutator is turned in the one direction for the transmission of one
current when one plunger is used and is turned in the other direction for the
opposite current when the other plunger is used I enclose the said plungers in a box
or case in front of the instrument half the upper front of which box or case is cut
away and provided with a revolving quarter circle screen so that one of the two
plungers as may be required is covered and protected when the other is open, free
or uncovered for use. I also provide a third plunger passing through this box and
through into the inside of the block instrument so that when this third plunger is
plunged it catches the line spring of the instrument and transmits a current in the
same direction as the last current sent as it in no way alters the commutator when
plunged. This third plunger replaces the ordinary separated bell plunger usually
made use of for this description of block instrument and this third plunger also
carries a releasing catch which has for its purpose the releasing of the before
mentioned quarter circle screen when this screen is covering the white plunger and
when "train out of section" is being sent by this plunger to the station in the rear.
I so arrange this releasing catch piece on the plunger that, it is not in use and so
does not catch the screen lock except after "train on line" has been given by the
station in the rear and until the starting signal, or other controlling signal for the
section in advance has been actuated to pull off the signal and the latter is again
placed in the danger position. This manipulation of the lever raises and places in
position the releasing catch piece on this plunger of the instrument at the same
box so that the next time the plunger is used after this manipulation of the said
signal lever the catch piece engages with a catch or locking piece securing the

page_text: screen and when this catch piece is released the screen by means of a spring
arrangement or by gravity revolves over the other plunger leaving the white o
liue clear plunger so that the signalınan may again use it when required. I also
provide a further screen upon a small lever which said lever projects outside the
box or case which covers up the plungers and this lever carries a small screer
marked "train passed" or bearing other suitable inscription and this covers up the
white plunger even when the large quarter circle screen has revolved over the other
plunger.
In some forms of Tyers or other single wire double line block the commutator has
to be specially unlocked or the commutator turned by hand into the right position
before plunging and then only one plunger is required both for plunging
"line blocked ""line clear" and the ordinary plunging for bell signals only. In
this case so arrange that when the commutator is turned from "line clear" into
the "line blocked" position it cannot be again turned to give when plunged the
"line clear indication until the lever of the starting signal or other signal
controlling the section in advance has been pulled off and again put to danger.
In the two or three wire system of needle or disc block working where in some
cases the tapper form of key or commutator is used and in others the drop handle
form the same as the ordinary drop handle single needle telegraph instrument I so
arrange and connect the lever and the block instrument that when the tapper key
or drop handle which transmits the line blocked current to the station in the rear
has been used the current necessary to indicate "line clear" to the station in the
rear cannot be sent until the lever actuating the starting signal or other controlling
signal for the section in advance has been first moved into the "allright" position
and again put to danger and I may do this by either preventing the necessary
contact being made to send the "line clear" current until such signal has been
manipulated as described or I may so interrupt or break down the circuit or some
local portion of it as to prevent the said "line clear" current being transmitted.
Of course where a three position block indicating apparatus is used with needle or
dise the said needle or disc may be allowed to fall to the zero position after the
train out of section signal has been transmitted but the interlocking by the
signal lever would be so arranged as to prevent the "line clear" current being
transmitted.
Instead of interlocking the block signalling apparatus with the lever of the said
starting or controlling signal or rice versa I propose in some cases by means of a
catch lever or armature to be actuated by an electro magnet to operate this
releasing arrangement so that "line clear" may not be sent to the station in the
rear until the train previously passing through the section has passed over a rail
contact some distance in advance of the starting signal or controlling signal of the
section in advance the electro magnet being in electrical connection with a battery
& the said rail contact and in this case I also propose in some cases that the giving
of this "line clear" to the station in the rear shall actuate the armature of an
electro magnet (or permanent magnet with soft iron pole piece) and thus unlock
the lever of the starting signal at the same place where and at the same time as
the line clear indication is given and shall keep such lever unlocked until the said
lever has either been actuated and the signal pulled off and again placed to danger
when it would automatically be relocked or until the "line blocked current is
transmitted or in the case of the three wire permanent current system until the
cessation of the said current for "line clear" and I propose to utilize parts or all
of these several devices separate or not or in combination as may be required and
in accordance with the requirements of the traffic or otherwise.
The rail contact which I propose to use simply a long lever with a short tail
piece for the purpose of fixing the said tail piece in a hole through the web of the
rail and so that the depression of the rail raises up the opposite end of the long
lever and by means of silver or other suitable contacts joining two connections or
parts of a circuit formed of springs carrying silver or other contacts and the piece
which connects these springs together may be adjustable on the end of the lever

page_text: and secured in position on an insulated boss. And so as to provide against the
sinking of the road or line of rails actuating or operating the rail contact I use a
strong timber to attach the first and fourth of four sleepers together leaving the
two intermediate sleepers loose and free from the timber attaching the first & fourth
sleepers together and I fix the said rail contact which is provided with a suitable
iron box firmly upon this strong connecting timber.
In some cases
propose to place this connecting timber underneath all four of
the said sleepers and by undercutting the two centre sleepers or cutting out slots
for the said sleepers in the longitudinal timber and bolting the whole of them down
to the said timber and removing the keys from the chairs of the two centre sleepers
I get the rail free from the bottom of the said chairs and therefore by the action
of the train going over the rail there is a true depression of the rail apart from the
subsiding or depression of the road and by all four sleepers being bolted together
by strong bolts any sinking of the rails takes place as a whole and not partially
therefore the distance between the bottom of the chairs of the two central sleepers
and the bottom of the rail passing through the chairs is always the same.
The
keys of course may be placed in the chairs again so as to prevent as far as possible
any lateral movement of the rails.
Dated this 2nd day of December 1892
FREDERICK T. HOLLINS.
"
COMPLETE SPECIFICATION.
Improvements in Block Signalling Apparatus and Interlocking same
with Outdoor Signals.
I FREDERICK THOMAS HOLLINS of Saltley House Forest Drive Leytonstone
Essex, Telegraph Engineer to the Great Eastern Railway Company 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:-
The object of this invention is to so interlock the block instrument for the
section in the rear with the lever working the outdoor signal controlling the section
in advance that when once a train has been accepted from the station in the rear
another train cannot be accepted on the block instrument again until the signal
lever at the home station controlling the section in advance has been actuated so as
to lower the signal and is put back to danger behind the train on its arrival and in
some cases to so arrange that the key or commutator used for sending the "line
clear" current cannot be used again to send the "line clear" current, or current to
indicate line clear" to the station in the rear until the train itself has passed out
of the section into the section in advance and the signal is to danger behind it and
further in some cases I arrange so that the starting signal or other signal controlling
the section in advance cannot be lowered for a train to start or enter the section in
advance without the concurrence and permission of the signalman at the signal box
or station in advance. This invention is applicable to all kinds of block instruments
either single wire block for double lines or the ordinary two or three wire block and
also to the needle form or to the disc form of block instrument.
"
In the simplest form and especially applicable to Tyers single wire block instru-
ments for double lines where a plunger is used to transmit the indication of "line
blocked' to the station in the rear and another plunger usually a white plunger in
the same instrument to transmit the "line clear" indication to the station in the
rear and where a commutator is used inside the said instrument and which said
commutator is turned in the one direction for the transmission of one current when
one plunger is used and is turned in the other direction for the opposite current
when the other plunger is used I enclose the said plungers in a box or case in front
of the instrument half the upper front of which box or case is cut away and
provided with a revolving quarter circie screen so that one of the two plungers as

page_text: may be required is covered and protected when the other is open, free or uncovered
for use.
I also provide a third plunger passing through this box and through into
the inside of the block instrument so that when this third plunger is plunged it
catches the line spring of the instrument and transmits a current in the same
direction as the last current sent as it in no way alters the commutator when
plunged. This third plunger replaces the ordinary separate bell plunger. usually
made use of for this description of block instrument and this third plunger also
carries a releasing catch which has for its purpose the releasing of the before
mentioned quarter circle screen when this screen is covering the white plunger and
when "train out of section" is being sent by this plunger to the station in the
rear. I so arrange this releasing catch piece on the plunger that it is not in use and
so does not catch the screen lock except after "train on line" has been given by
the station in the rear and until the starting signal or other controlling signal for
the section in advance has been actuated to pull off the signal and the latter is
again placed in the danger position. This manipulation of the lever raises and
places in position the releasing catch piece on this plunger of the instrument at the
same box so that the next time the plunger is used after this manipulation of the
said signal lever the catch piece engages with a catch or locking piece securing
the screen and when this catch piece is released the screen by means of a spring
arrangement or by gravity revolves over the other plunger leaving the white or
"line clear" plunger so that the signalman may again use it when required. [
also provide a further screen upon a small lever which said lever projects outside
the box or case which covers up the plungers and this lever carries a small screen
marked "train passed" or bearing other suitable inscription and this covers up the
white plunger even when the large quarter circle screen has revolved over the other
plunger.
"
In some forms of Tyer's or other single wire double line block the commutator
has to be specially unlocked or the commutator turned by hand into the right
position before plunging and then only one plunger is required both for plunging
line blocked" "line clear" and the ordinary plunging for bell signals only. In
this case I so arrange that when the commutator is turned from "line clear" into
the "line blocked." position it cannot be again turned to give when plunged the
"line clear" indication until the lever of the starting signal or other signal
controlling the section in advance has been pulled off and again put to danger.
"
In the two or three wire system of needle or disc block working where in some
cases the tapper form of key or commutator is used and in others the drop handle
form the same as the ordinary drop handle single needle telegraph instrument i
so arrange and connect the lever and the block instrument that when the tapper
key or drop handle which transmits the line blocked current to the station in the
rear has been used the current necessary to indicate "line clear to the station in
the rear cannot be sent until the lever actuating the starting signal or other con-
trolling signal for the section in advance has been first moved into the "alright"
position and again put to danger and I may do this by either preventing the
necessary contact being made to send the "line clear' current until such signal
has been manipulated as described or may so interrupt or break down the circuit
or some local portion of it as to prevent the said "line clear current being
transmitted. Of course where a three position block indicating apparatus is used
with needle or disc the said needle or disc may be allowed to fall to the zero position
after the train out of section signal has. been transmitted but the interlocking by
the signal lever would be so arranged as to prevent the "line clear" current being
transmitted.
"
Instead of interlocking the block signalling apparatus with the lever of the said
starting or controlling signal or vice versa I propose in some cases by means of a
catch lever or armature to be actuated by an electro magnet to operate this
releasing arrangement so that "line clear may not be sent to the station in the
rear until the train previously passing through the section has passed over a rail
contact some distance in advance of the starting signal or controlling signal of the

page_text: section in advance the electro magnet being in electrical connection with a battery
and the said rail contact and in this case I also propose in some cases that the
giving of this "line clear" to the station in the rear shall actuate the armature of
an electro magnet (or permanent magnet with soft iron pole piece) and thus unlock
the lever of the starting signal at the same place where and at the same time as the
line clear indication is given and shall keep such lever unlocked until the said lever
has either been actuated and the signal pulled off and again placed to danger when
it would automatically be relocked or until the "line blocked" current is trans-
mitted or in the case of the three wire permanent current system until the cessation
of the said current for "line clear" and I propose to utilize parts or all of these
several devices separate or not or in combination as may be required and in
accordance with the requirements of the traffic or otherwise.
The rail contact which I propose to use is simply a long lever with a short tail
piece for the purpose of fixing the said tail piece in a hole through the web of the
rail and so that the depression of the rail raises up the opposite end of the long
lever and by means of silver or other suitable contacts joining two connections or
parts of a circuit formed of springs carrying silver or other contacts and the piece
which connects these springs together may be adjustable on the end of the lever
and secured in position on an insulated boss. And so as to provide against the
sinking of the road or line of rails actuating or operating the rail contact I use a
strong timber to attach the first and fourth of four sleepers together leaving the
two intermediate sleepers loose and free from the timber attaching the first and
fourth sleepers together and I fix the said rail contact which is provided with a
suitable iron box firmly upon this strong connecting timber.
In some cases I propose to place this connecting timber underneath all four of
the said sleepers and by undercutting the two centre sleepers or cutting out slots
for the said sleepers in the longitudinal timber and bolting the whole of them down
to the said timber and removing the keys from the chairs of the two centre sleepers
I get the rail free from the bottom of the said chairs and therefore by the action
of the train going over the rail there is a true depression of the.rail apart from
the subsiding or depression of the road and by all four sleepers being bolted
together by strong bolts any sinking of the rails takes place as a whole and not
partially therefore the distance between the bottom of the chairs of the two central
sleepers and the bottom of the rail passing through the chairs is always the same.
The keys of course may be placed in the chairs again so as to prevent as far as
possible any lateral movement of the rails.
And in order that my invention may be more fully understood I will now proceed
to describe the accompanying drawings with reference thereto.
Fig. 1 is a plan of a complete set of Tyer's single wire double line block
apparatus, the upper portion marked A representing the alarm bell for the ordinary
sound signals and B the actual block instrument for an up or down double line of
railway the upper needle or pointer having reference to the down line and the
botton needle or pointer having reference to the up line. The bottom portion of
this block instrument marked C shows my improved interlocked screen and dise
arrangement, the dark portion D on the upper left hand side of C represents the
screen and as shown is covering up the red or "train on line" plunger. The
disc E attached to the small lever F on the upper right hand side is in front of
and covers the white or "line clear" plunger of the block instrument. The
rod H projecting out at the bottom is in actual practice attached by means of a
simple crank arrangement to the tail piece of the signal lever actuating the starting
or controlling signal for the section in advance whilst the screen and disc
arrangement C is covering and protecting the plungers of the block instrument for
the section in the rear.
Fig. 2 is a plan of my interlocked screen and disc arrangement with the front
removed drawn full size in order to the better explanation of the several parts.
A is a case or receptacle of metal or otherwise as desired for the purpose of
boxing or covering up the red and white plungers marked X. B is the large

page_text: screen described and shown in Fig. 1 on the upper left hand side covering the red
or "train on line plunger and the axis of the screen is at C. This screen B
revolving upon this axis may be turned by means of the knob L so as to cover the
"train passed", disc G which in its turn is covering the white or "line clear"
plunger as previously described. As shown in the drawing the apparatus is in its
normal position the line being "clear" the previous train having passed out of the
section. The signalman receiving the "be ready" for a train from the signalman
in the rear would depress the lever I on the upper right hand side which having its
axis at M raises the train passed disc G thus enabling the signalman to depress the
white or "line clear" plunger X which by the action of the current would indicate
. "line clear"
on the upper portion of the block instrument Fig. 1 at the station in
the rear.
On leaving loose of the lever I after plunging the "train passed" disc
of course again falls in front of and covers up the white or "line clear" plunger X.
On the signalman receiving the "train entering section" signal he turns the
screen B by means of the knob L from left to right so as to cover up the "train
passed" disc and white plunger and discloses to view the "train on line " disc and
red plunger by means of which plunger he immediately acknowledges, by depressing
the same, the "train entering section" signal. This by means of the electric
current turns the upper needle or pointer of the block instrument at the station in
the rear from "line clear" to "train on line." When the quarter circle screen B
is turned over from left to right the catch piece D upon its axis (and which is
bevelled) engages with the spring catch E which it pushes back and when partly
turned E snaps forward and holds D so that the screen cannot come back. The
spring catch E is a double one and the lower darkened portion N is a second catch
upon the same spring so that as the screen B is turned further round the catch D,
when the screen is completely over to the right, is again caught by this second
catch N. The object is to secure that before the red or "train on line" plunger
can he got at the screen shall be locked over the white plunger so that it cannot by
ordinary means be pulled completely back over the "train on line" plunger without
the full manipulation of the apparatus as intended. The knob P at the left hand
upper side of the case A is merely for the purpose of grasping with the fingers to
enable the "train on line" plunger to be more easily manipulated with the thumb
if so desired. On the approach of the train the signalman lowers his starting or
other controlling signal for the section in advance and in doing so he raises the
rod at the bottom of the instrument. This rod H has a crank or catch piece T
which when the rod is raised engages with and raises the releasing catch piece F
having a projection or heel V and an upper projection or disengager Y. This
releasing catch piece F forms a sleeve the axis of which is the rod of the round
plunger a (Figs. 1 and 2) and moves backwards and forwards with this.plunger
when the latter is plunged but when in the position shown in Fig. 2 this catch piece
does not manipulate or interfere with anything. When however the rod H is
raised F is also raised and is caught and held up by the front of the two teeth in
the catch piece W which is depressed on the raising of F and pressed back to the
position indicated by the spring b at the same time the raising of the catch piece F
lowers its tail piece or disengager Y in front of the bevelled catch piece on the
catch E previously described as holding the screen B by means of the projection or
catch piece D. In addition to this the screen B, when turned over to cover the
"train passed "dise is caught and held by the hook or projection J engaging with
a catch on the back of the screen and which is not shown in the drawing. In
addition to this whilst the signal is in the "off" position and therefore the rod H
raised so that the projection S fixed at its upper end would reach to about the
position marked R this projection S would stand in front of and engage with the
projection K at the back of the screen B the object being to prevent the screen
from going over by any manipulation of the plunger a whilst the signal is in the
"off" position. When the train has passed the starting or controlling signal the
latter is again put to danger and the rod H is by this act also lowered leaving
the catch piece F still caught up and held up by the catch piece W and the

page_text: screen B being still over the "train passed" dise leaving disclosed the "train on
line" or red plunger, the signalman after putting his signal to danger depresses the
small lever I on the right hand side and at the same time depresses the middle
plunger a. The raising of the small lever I releases the screen at J where it is
caught by the projection or hook J and the depression of the middle plunger a
presses forward the catch piece F and its tail piece or disengager Y also depresses
the bevelled catch piece c and catch piece E N and thus releasing the catch D on
the screen B. The pressure of the spring d affixed to the block e and the pro-
jection throws the screen over from right to left thus disclosing the "train
Fig. 3 more clearly indicates the shape and formation of the catch piece Dand
the axis or sleeve C of the screen B. The parts marked R R1 R2 are merely
partitions to separate one portion of the case or box from the other so as to
prevent any possible tampering with the apparatus and the part marked Z on the
rod H is also for a similar purpose. The parts marked indicates a slot in which
the rod H moves.
passed" disc.
The object of the projecting hook J on the "train passed" dise G is to hold the
screen in cases of special emergency so that even if the signal lever for the section
in advance has been taken off it may be put to danger again and ordinary signals
sent on the apparatus without releasing the screen. For instance, if the "train
entering section" signal has been given, the signalman may have lowered his signal
for the train and he may afterwards receive the "stop and examine train" signal
which would cause him to have to put his signal to danger again and send the usual
sound signals. All this may be done therefore so long as lever I is not depressed"
the catch hook J holding the screen from going over and thus prevents the signal-
man having the false indication of "train passed" when if he stops and examines it
it will not be passed. Again the break down of a train before reaching the signal
may necessitate a similar operation.
Fig. 4 indicates this interlocked screen and disc arrangement where the screen is.
to be released not by the manipulation of the signal lever but by the actual passing
of the train itself over a rail contact fixed in advance of the signal controlling the.
section in advance. The screen B is precisely the same as in Fig. 2 but the catch
piece D'on its axis C is slightly different being made to coincide with the two cogs
or steps e el on the armature F of the electro magnet E E. On turning the
screen B over from left to right the catch D first engages with el and, as it goes
further over with e. The coils of the electro magnet are in circuit with a battery
and the rail contact shown in Figs. 7 and 8. As the train passes over this rail
contact the circuit with the battery is completed and the current passing round the
coils E E' pulls down the armature F and thus releases the screen which being
provided with a spring as shown at d in Fig. 2 revolves over from right to left and
discloses the "train passed" disc. In case of the failure of the rail contacts to
actuate this electro magnet and release the screen, a small press button is provided
in the signal box in a lock up case baving a paper front which paper has to be
torn before the press button can be got at so that the depression of this press
button sends a current round the coils E E' equivalent to the current sent when a
train passes over the rail contact.
In both cases (Figs. 2 and 4) I make the screen B of such dimensions that in
revolving it round, the white plunger is covered up before the red plunger is
disclosed so that the screen cannot be held in a middle position in order to operate
first one plunger and then the other. In some cases I fix a key piece on the back
of the screen B and a corresponding piece on the train passed disc G so that imme-
diately the screen commences to turn from left to right they so engage with each
other that the key piece on the screen B prevents the "train passed" disc G being
raised and this is an additional security inasmuch as it absolutely prevents the
plunger being alternately manipulated without the proper and full manipulation of
the screen B. There is of course also another catch piece on the back of the

page_text: screen B which as the screen revolves over from left to right engages with and is
caught by the projection or catch J of the train passed disc G.
Fig. 5 illustrates one form of electric lock used for locking the signal lever so
that the signal lever cannot be taken off without the permission of the signalman
at the signal box in advance.
"
A is the iron base upon which the several parts are fixed. B is a lever having
a slot C and which is by means of rodding and suitable gearing connected to the
tail piece of the signal lever and when unlocked the said lever B is free to move on
its axis D. The lever, B carries a spring controlled catch piece E at the opposite
end to the slot C. F is an electro magnet having an armature H with its axis I.
and balance weight K and is actuated by the current sent from the signal box in
advance. L is a strong extending piece also on the axis and forms a part of this
armature and which is the bolt or stop piece to prevent when in the position shown
in the drawing, the lever B being manipulated. M is a projection on the bolt or
stop piece for the purpose of engaging with the catch on the small lever N. The
disc marked "locked" and "free" is geared at O to the balance weight K of the
armature and to counterbalance the weight of this disc the counterbalance P is
provided. When a current sufficiently strong passes round the electro magnet F
the armature H is attracted and the bolt or stop piece L is pulled towards the
right and the lever N being free to fall engages with the projection M and this
holds the lever B unlocked and the signal lever is free. This movement also raises
the disc or indicator so that instead of "locked "appearing in front of the aperture
in the cover of the lock the word "free" is indicated, thus indicating to the signal-
man that his lever is "free
66
or unlocked." When the signal lever is taken off
the lever B of the lock is raised at the slotted end C and is of course depressed at
the opposite end and the lever E fixed thereon engages underneath the small
lever N. When the signal is again put to danger the lever B is again raised
and E lifts up N and releases the bolt or stop piece L and by means of the balance
weight it again locks the lever B. The disc also again falls and indicates "locked."
In case of failure or for other reasons a small plunger is provided, and fitting
through the cover of the instrument, so that the lock may be mechanically unlocked.
The depression of this small plunger pushes forward a small lever S bevelled at its
side and this pressing upon the bevelled surface R of the balance weight K unlocks
the lever. In doing this S also pushes forward an index wheel T having con-
secutive numbers on the sides and the pointer U indicates a number on that wheel
corresponding with the number of times the small plunger has been manipulated.
It is sometimes necessary after this lever has been unlocked as in the case of the
cancelling signal to relock it mechanically without manipulating the signal lever
and this is done by simply depressing the tail piece V of the lever N. In order to
assist the bolt or stop piece I in the action of relocking, in the act of putting the
signal to danger I prefer to fix a spring W so as to sharpen the movement but so
that the spring acts only whilst the armature is close to the poles of the magnet.
I also place two stop pins X X together with the spring Z on the lever B in
order to ensure the proper engagement of E with the small lever N. To use the
electric lock in connection with the screen and disc arrangement fitted to the block
instruments as shown in Figs. 2 and 4 it is desirable that the depression of the
white plunger shall introduce extra battery power so that the ordinary battery used
for the block instrument although sufficient for working the latter shall not be
sufficient to manipulate the electric lock. And it is also desirable to arrange a
catch for the white plunger to prevent it being used more than once for each train
but it is not necessary to fully describe by diagram how I prefer to do this. But
broadly this is done by the depression of the white plunger depressing a simple key
switch joining up an extra battery so that by the time the plunger reaches the line
spring to press it in contact with the battery contact, the extra battery is in circuit
and the act of depressing the plunger releases a catch piece which as the white
plunger recedes back into its normal position drops into a slot and thus locks the

page_text: white plunger. Either the manipulation of the signal lever working the controlling
signal for the section in advance or the plunging of the red plunger can be made to
reset this catch piece ready for use when next the white plunger is plunged.
Fig. 12 indicates diagramatically how the extra battery is joined up by plunging
the white or line clear plunger. C and Z indicate the ordinary carbon and zinc
terminals of a Tyers block instrument. A is the ordinary battery consisting of a
suitable number of cells and B is the extra battery, normally the connections are as
shown but when plunging the white plunger K is pushed forward out of contact
with D into contact with E and Y terminal (zine) of battery A is joined to X¹
terminal (carbon) of battery B and therefore both batterys are joined in series by
the time the commutator reaches the line springs to send the current to line.
"
Fig. 6 indicates how I prefer to interlock another form of Tyers block instrument
with the signal lever. The circular disc A forms a part of and is upon the same
axis as the commutator of the instrument and B indicates the plunger passing
through the centre. In this form of Tyers block instrument when the commutator
is over on the left hand side the mechanical disc indicates "train on line" and the
connections are arranged for the depression of the plunger B to send a current of
right sign or in the right direction to indicate "train on line on the block
instrument at the other end of the section. And when the commutator is turned
from left to right the mechanical disc indicates "line clear" and the connections
are right for sending the correct current for indicating "line clear" on the block
instrument at the opposite end of the block section. Now as shown in Fig. 6 the
commutator is in the position and locked in that position for sending "train on line."
It is locked by the lever C having its axis at D and with the tail piece E. When
the signal is taken off on the approach of a train the lever F which is geared to the
signal lever is raised in the direction of the arrow and the tail piece of the same as
shown presses forward E and raises the lever C out of the slot H in the disc A and
the pin or catch piece I on the lever C is caught and held by the catch piece J.
F in pressing E forward also pushes forward the rod or slide K having a projection
or catch L. This catch L passes by the knuckle joint M at the end of the stem N
of the "train passed" disc O and stops in front of the projection P on the circular
disc A. If it were not for this arrangement the taking off of the signal lever and
whilst the signal was "off" would admit of the commutator being turned in the
right direction for sending "line clear" again before the line was clear but the
projection L prevents this while the signal is in the off position. When the signal is
again put to danger this slide rod K is pulled back out of the way of the
projection P and in doing so again engages with the knuckle joint and pulls over
the "train passed "disc O in front of the aperture of the instrument thus indicating
to the signalman that the train has passed." is a small lever with its axis at / and
geared to the circular disc A at m and is for the purpose of turning the "train
passed" disc O back to the position shown by means of the catch n when the
When the
commutator is again turned to give line clear for a following train.
commutator is again turned over in order to give "line clear" for another train
the cam piece or projection R on the circular disc A raises the elongation of the
catch lever J and thus releases the lever C which falls against the periphery of the
circular disc A ready to re-engage with the slot H when the commutator is again
turned back to the position shown in the drawing.
Fig. 7 is a longitudinal view and Fig. 8 an end elevation of the rail contact I
propose to make use of. A is the iron containing case or box having a water tight
cover to protect the apparatus from the weather. B is a large heavy lever having its
axis at C and D is the tail piece of the said lever and which tail piece is intended
to fit through a hole in the web of the rail. E is the contact piece fitted on to the
end of the lever B but insulated from it by the insulating piece F. The slot H in
the contact piece E is for the purpose of allowing the contact piece to be moved
either higher or lower by means of the set screws I I¹. KK are the contact
springs secured upon a block of ebonite or other insulated material L by means of
B

page_text: the brass cocks M M'. Each of the springs K K¹ carry contact pieces N N' of
silver, platinum, or other suitable material and insulating bosses 001 for the
purpose of holding the contact point clear from rubbing upon the insulation and
thus by friction coating the same with a metal deposit. The depression of the rail
of course raises this contact piere up so that E joins together the springs K K by
means of the contact point N N one spring being in connection with the battery
and the battery with earth and the other spring in connection with the line and the
unlocking magnet E E Figure 4.
Figs. 9 and 10 indicate how 1 propose to fix this rail contact so as to ensure its
satisfactory working. A is a longitudinal timber preferably fixed underneath the
first and fourth of four sleepers acting as a bearing for the said sleepers and D
indicates an angle plate for the purpose of securing this longitudinal timber to the
first and fourth sleepers. It will be seen that the second and third sleepers
marked CC have been cut away shorter than the first and fourth so that these two
intermediate sleepers shall not rest upon the longitudinal timber. A block is
securely fixed to this longitudinal timber at a point E between the second and third
sleeper to accommodate the rail contact. The rail contact is thus held firmly by
the longitudinal timber and as the tail piece of the rail contact passes through the
web of the rail each time the train passes over, the rail is depressed and the rail
contact actuated as described.
Fig. 1 shows another method of doing this but without shortening the two
intermediate sleepers. The longitudinal timber passes underneath all four sleepers
but the two intermediate sleepers are undercut so that they are not actually
pressing upon the longitudinal timber. This allows of sufficient free movement to
ensure the rail contact being actuated.
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. The combination with a block telegraph instrument for the section in the
rear of a box or case covering up the plunger or plungers and a movable screen to
cover or partially cover them controlled by the lever of the controlling signal for
the block section in advance substantially for the purpose as set forth and
described.
Second. The combination of an interlocked screen for covering up or preventing
the use of the wrong plunger or key of a block telegraph instrument for the section
in the rear and a releasing device for releasing or setting for release the said screen
by the manipulation of the signal lever of the controlling signal for the block
section in advance substantially as set forth and described.
Third. The combination of a screen or equivalent device for alternately covering
up or preventing the wrong use of the plungers or keys of a block telegraph
instrument the said screen being automatically controlled by the signal lever for
tbe block section in advance so that the screen will not admit of line clear being
given for the section in the rear until the controlling signal for the block section in
advance has been taken off and again put to danger and a releasing lever and
engaging device on central or other plunger used for giving "train out of section
substantially as set forth and described.
"
Fourth. With a block telegraph instrument the interlocked screen and releasing
device to set for releasing the screen from over the line clear plunger by the
manipulation of the signal lever and the engaging device on the central or other
plunger for engaging with the releaser in combination with a lever catch similar or
equivalent to the one carrying the "train passed" disc shown in Fig. 2 for the
purpose and in the manner substantially as set forth and described.
Fifth. A block telegraph instrument with interlocked screen and disc arrange-
ment as indicated controlled by the working at any given signal station of the lever
of the signal controlling the entrance to the section in advance substantially as set

page_text: forth in combination with an electric locking instrument at the signal box in the
rear for controlling the movements of the lever of the signal controlling the entrance
to the section between the two signal stations substantially as described.
Sixth. An electric locking instrument for locking or controlling the use of signal
levers, which on being unlocked and the signal taken off and put to danger again
automatically relocks such signal lever or levers in combination with an interlocked
screen and disc for covering up or controlling the use of the key or plunger or
commutator of a block telegraph instrument or equivalent device by the use of
which key or plunger or commutator the said electric lock is unlocked or the use
thereof controlled substantially as set forth and described.
Seventh. An electric lock capable after manipulation in working of automatically
relocking the signal controlling the entrance to a block section in combination with
a screen controlling substantially in the manner and for the purpose indicated the
use of the keys or plungers or commutators used for sending an electric current to
operate the said electric lock and which screen is interlocked with the lever of the
signal controlling the entrance to the block section in advance substantially as set
forth and described.
Eight. A Tyers or other single wire double line block telegraph instrument whose
indications of the state of a block section vary as the direction of the electric
currents transmitted are varied by the manipulation of a commutator or commutators
and the turning or changing of which commutator or commutators is controlled by
the manipulation of the lever of the signal controlling the entrance to the block
section in advance substantially as set forth and described.
Ninth. Such a block telegraph instrument having such commutator or com-
mutators interlocked by the lever of the signal controlling the entrance to the
section in advance in combination with an electric lock for controlling the working
of the signal controlling the entrance to the section in the rear that is the section
for which the interlocked commutator or commutators arrange the direction of the
currents to indicate the state of the line on the block instrument at the opposite end
substantially as set forth and described.
Teuth. In a block telegraph instrument having keys or plungers and a screen to
alternately or otherwise cover or protect the same and an electro magnet for
releasing the same from over the line clear plunger in combination with a rail
contact the manipulation of which by a passing train or part of a train transmits or
allows to be transmitted the necessary current for electro mechanically releasing
the said screen substantially as described and illustrated in Fig. 4.
Eleventh. The method of fixing rail contacts by carrying the same upon a
longitudinal timber attached securely and immovable underneath or to the sleepers
the intermediate sleepers not being attached but free to allow the depression of the
rail to actuate the said rail contact substantially as set forth and described.
Dated this Sixteenth day of August 1893.
FREDERICK T. HOLLINS.