Improvements in Mechanical and Electrical Interlocking of Railway Signals, Signal or other Levers, and Block Telegraph Instruments, commonly called Lock and Block.
Year: 1892

page_text: Date of Application, 15th Dec., 1892
Complete Specification Left, 30th June, 1893-Accepted, 23rd Sept., 1893
PROVISIONAL SPECIFICATION.
Improvements in Mechanical and Electrical Interlocking of Railway
Signals, Signal or other Levers, and Block Telegraph Instruments,
commonly called Lock and Block.
We, ALEXANDER Ross, of London Road Station, Manchester, in the County of
Lancaster, Engineer to the Manchester Sheffield and Lincolnshire Railway
Company, THOMAS WHARMBY, of 18 Audenshaw Road, Guide Bridge, in the
said County, Signal Inspector to the said Company, and ROBERT STUART
HAMPSON, of Godley Junction, in the County of Chester, Telegraph Superin-
tendent to the said Company, do hereby declare the nature of this invention to be
as follows:-
Our invention relates to an improved method of and means for combining the
mechanical interlocking of railway signals, signal levers and points levers, and any
other part in the connections therewith with the electrical block apparatus of what-
ever kind or description employed.
For convenience of description let it be supposed that a train is waiting to enter
a section at cabin A. The starting signal at A is according to our improvements
electrically locked and controlled by cabin B and is also mechanically forced and
held in the locked position by a special mechanical arrangement preferably
connected with the trigger catch or lever in cabin A which effectually protects the
electrical lock against atmospheric or other stray electricity or other interference
on his
or failure which could result in unlocking. Cabin B gives "line clear"
electrical block instrument to cabin A and in so doing partially unlocks A's starting
signal which is completely unlocked when the signalman in cabin A raises the lever
catch of the starting signal or otherwise releases the above mentioned mechanical
contrivance. We have also a special electrical arrangement either in connection
with the starting signal lever or the lever catch which when the lever is worked
disconnects the electrical lock circuit and re-connects it again when the lever
returns to its normal position. The block instrument at cabin A is fitted with a
special electrical arrangement which permits the ordinary electric block signals to
be given without interfering with the electrical lock circuit.
Cabin A gives cabin B train in section" and cabin B accepts the train and
then moves the handle of his block instrument to the "train on line" position and
to retain the handle in that position a special mechanical locking arrangement is
provided which the signalman is compelled to move. When the signalman has
made this movement "line clear" cannot be given until the signal (or signals) has
been taken off for the train to leave the section and the same has again been put to
the danger position which liberates the handle of the block instrument so that
"line clear" can be given for another train.
The special mechanical locking arrangement above mentioned consists of a
sliding plate fitted in the stand or lower part of the block instrument and in this
plate is a groove or slot which is engaged by a pin or projection on the end of the
block instrument handle; the form of the groove or slot is such that when the
sliding plate is pushed back the handle of the block instrument is free but when
the sliding plate is drawn partly forward the block instrument handle is locked in
the line clear" position, and when the sliding plate is drawn forward as far as
The back end of the
possible the handle is locked in the "train on line" position.
sliding plate is coupled to lever and rod connections which control the mechanical
locks in connection with the signal levers which correspond to the respective
positions of the block instrument handle above indicated.
We also so connect the electrical lock in all "three position" block instruments

page_text: that when the needle indicates "line blocked" in cabin B the starting signal at
cabin A is locked.
These electrical and mechanical arrangements can be applied to all interlocking
and other frames and to every known kind and description of electrical block
instruments.
We have described our various improvements and arrangements for combining
the interlocking of electrical and mechanical signals levers and instruments as
applied to the starting signal lever but it will be readily understood that it can be
applied to any other lever.
Dated this 14th day of December 1899
H. B. BARLOW & GILLETT,
Agents for Applicants.
SPECIFICATION.
COMPLETE
Improvements in Mechanical and Electrical Interlocking of Railway
Signals, Signal or other Levers, and Block Telegraph Instruments,
commonly called Lock and Block.
We, ALEXANDER Ross, of London Road Station, Manchester, in the County
of Lancaster, Engineer to the Manchester Sheffield and Lincolnshire Railway
Company, THOMAS WHARMBY, of 18 Audenshaw Road, Guide Bridge, in the
said County, Signal Inspector to the said Company, and ROBERT STUART
HAMPSON, of Godley Junction, in the County of Chester, Telegraph Superin-
tendent to the said Company, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement :-
Our invention relates to an improved method of and means for combining the
mechanical interlocking of railway signals, signal levers and points levers, and any
other part in the connections therewith, with the electrical block apparatus of what-
ever kind or description employed.
And in order that our invention may be fully understood and readily carried into
effect we will describe the same with reference to the accompanying nine sheets of
drawings in which—
Sheet 1. Figure 1 is a diagram of an up and down main line, sidings and cross
over roads illustrating the application of our improvements in combining the
mechanical and electrical interlocking of railway signals, signal and points levers,
and block instruments.
Sheets 2 and 3.-Figure 2 is a front elevation of the frame of signal and points
levers in one of the cabins A. B. C. Fig. 1, showing the electrical block signal
instruments, the levers and locking cases with the ordinary as well as our improved
interlocking mechanism.
Sheet 4. Figure 3 is an end view of Fig. 2.
Sheet 5. Figures 44, 4B, 4°, are plans respectively of three locking cases showing
the lever and slide tappets and the interlocking therefor in either of the
cabins A. B. C. Fig. 1, and Fig. 5 is a side elevation of one of the slide tappets
which we employ in the alternative arrangement when a pivoted tumbler
is not used.
Sheet 6. Figure 6 is a side elevation and Fig. 7 a front sectional elevation of
the special mechanical locking arrangement consisting of a sliding plate which
we employ in combination with the handle of each pegging or receiving electrical
block sigual instrument in each cabin A. B. C. Fig. 1. Figures 8, 9, 10. are plans
showing the sliding plate in three different positions respectively normal or "line
blocked," "line clear," and "train on line."
Sheet 7. Figures 11, 12, 13, and 14, are detail views of the starting signal lever
tappet, the electrical block signal instrument slide tappet, pivoted tumbler, and the
electro magnet suspended lock which we employ according to our invention.

page_text: Sheet 8. Figure 15 is a side sectional elevation and Figs. 16, 17, 18, are plans
showing in three different positions respectively the starter and slide tappets and
the electro magnet lock as on Sheet 7, but with an alternative arrangement for
the tumbler. Fig. 19 is a detail of the electro magnet lock and slide tappet.
Sheet 9.-Figures 20 and 21 are end and side elevations respectively of the
arrangement of switch which we prefer to employ to make and break the electric
lock circuit.
In the diagram, Figure 1.-A. B. C. are three signal cabins, their respective
up line home signals are marked 2, up line starting signals 3, disc signals 4, and
up line siding points 5, disc signals 6 and 8, and cross over points 7, down line,
siding points 9, and disc signals 10, down line starting signals 11, and down line
home signals 12.
In Figures 2 and 3 the levers are numbered from 1 to 13 and the numbers 2
to 12 correspond to the signals and points bearing the same numbers in Fig. 1.
The four electric block signal instruments are lettered D D' E E' and if it be
supposed for convenience of description that we are looking at the interior of
cabin B, then D is the instrument by which B sends to A, E the instrument on
which he receives from A, and D₁ the instrument by which he sends to C and
E' the instrument on which he receives from C.
To the handle G of each receiving instrument E E' is applied a sliding plate H,
shown in detail and in three different positions on Sheet 6. This slide H, which is
fitted in the stand or lower part of the instrument, is made in two parts and insulated
from the block instrument, and also, by suitable material I, from a lever J which is
fulcrumed at J and by which it is connected to the special tappets K L or K' L'
(hereinafter described) in the locking cases 0³ 0.
The drawings show five locking cases 0, 0, 0, 0, 0, of which two O and O¹
require no description as they are for the ordinary mechanical interlocking of the
signal and points levers, and the remaining three 0³, ()³, 0%, are for our improved
combined mechanical and electrical interlocking.
To the tappet (3, 11) of each starting signal lever (3, 11) and to the special slide
tappet (K, K¹) is applied an electro magnet suspended lock P which is operated
by two pairs of electro magnet coils Q connected by wires R to spring contact
makers S in connection with the handles F.and G of all the electric block signal
instruments both up and down, and a relay U is provided at any suitable place in each
main electric circuit for both up and down lines to work the electric locks P. The
arrangement of spring contact makers applied on either side of the handle of each
block instrument D Di permits the ordinary signals to be given without interfering
with the electrical lock circuit.
The springs S which are fixed in the down line sending block instrument D in
each cabin are for disconnecting the local lock circuit R so that when the signalman
is forwarding a train the springs S are disconnected by the movement of the
instrument handle and prevent the local lock circuit R being completed and thus
prevent the electric lock which forms the armature being influenced.
The springs S in the up line sending block instrument D' work exactly in the
same manner as the springs fixed in the down line sending block instrument D.
The springs S in the up line receiving instrument E are for partially connecting
or closing the electric lock local circuit R when the block instrument slide H is
drawn out to "train on line " position.
The springs S in the down liue receiving instrument El work in the same
way as the springs fixed in connection with the up line receiving block
instrument E.
The relay U is an ordinary polarized relay and is actuated whenever the block
instrument is being worked in the following manner :-
Supposing A sends a train to B,-A moves the handle of the up line sending
instrument which sends a current along the block instrument line wire and through
the relay U and B's receiving block instrument E and so completes the inain circuit.
The armature of the relay U is attracted by the current Howing along the line

page_text: wire, when B acknowledges a train and draws out his block instrument slide H to
"line clear," the copper current now flows along the line wire, giving the "line
clear" indications on the sending block instrument dial in A and the receiving block
instrument dial in B cabin and also by exciting the electro magnet coils of the
relay U deflects the armature of the relay onto the right hand contact screw and
completes the electric lock local circuit R.
The lock battery is now brought into action and the current flows from the copper
end of the battery along the local circuit R to the right hand contact stud and
spring S fixed in the down line sending instrument at A, then through the relay
armature and the right hand contact screw, to the left hand terminal on the
electric switch Z to the contact stud 25 and contact stud 24 and right hand terminal
of the electric switch Z then through the electro magnet coils to the zinc end of the
battery.
The local circuit R being now complete the electro magnet coils Q attract the
armature and withdraw the lock P out of the starting signal lever tappet.
On the starting signal lever being pulled over the local lock circuit R is dis-
connected by means of the switch Z and the armature which forms part of the
lock P being thereby released, B sends the "line clear" signal to C by working
the block instrument D' but has no influence over his own electric lock circuit R
as the springs S are disconnected whenever the handle of the block instrument is
moved in either direction.
"
A now sends "train on line to B, B then draws his slide H to "train on line'
position which moves_the block instrument handle and depresses the springs S in
the block instrument E, and partially closes the electric lock local circuit R and
sends a zinc current along the line wire; and gives "train on line" indications on
the sending block instrument dial in A and the receiving block instrument dial
in B cabin and also reverses the armature of the relay Ü at cabin A to the left
hand contact screw and completes the electric lock local circuit R which again
brings the local lock battery into action.
The current.flows from the copper end of the battery to the right hand contact
stud and spring S fixed in the down line sending block instrument at A, then
through the relay armature and left hand contact screw of the relay U and then
to the contact stud and springs S fixed in the same block instrument at A, then to
the springs S fixed in the receiving instrument at A and through the electro
magnet coils to the zinc end of the battery.
The local circuit R now being completed the electro magnet coils Q attract the
armature and withdraw the lock P out of the tappet in connection with the
instrument slide H at A which enables A to put his instrument slide back.
In order to break the electric lock local circuit we employ a switch shown in
detail on Sheet 9 and arranged as follows:-
Below the lever frame are two shafts V supported in bearings and placed in line
with one another. On these shafts are fixed a number of ratchet wheels W namely
three on each shaft V. Each ratchet is worked so as to turn its shaft V in the
direction indicated by the arrow Fig. 21, by means of a pawl carried by
connections X from the balance or back weight levers Y of the home signal
levers 2 and 12, and the cross over road points lever 7, as hereinafter explained.
In the switch box or casing Z is fixed a spring 20 on which are formed two pro-
jections or catches 21, 22, of which the catch 21 engages the ratchet W and the
catch 22 latches an elbow lever 23 pivoted on an electric contact maker 24 and
kept normally resting against the other contact maker 25 by means of a spring 26.
Above the elbow lever 23 is fitted a stud 27, which, when the starter lever 3 or 11,
is pulled over, is depressed by an arm 28 fixed on the balance or back weight
lever in connection with the starter lever 3 or 11 and so moves the elbow lever 23
into the position shown in full lines, Fig. 21, away from the contact maker 25 and
breaks the electric lock local circuit served by the relay U.
A finger 29¹ is secured upon a stud 29 and forces back the spring 20 holding it
normally in the position indicated by dotted lines in Fig. 21; but when the slide H

page_text: is drawn to the "line clear" or "train on line" position the stud 29 by means of
lever and rod connections 30 is turned and the finger 291 moving in the direction
of the arrow, Fig. 21, releases the spring 20 which instantly comes over and latches
the elbow lever 23 after the latter has been moved away from the contact maker 25
by pulling over the starter lever 3 or 11 as above described. The switch is re-set
and the electric lock local circuit closed whenever the shaft V is turned by either
the home signal lever 2 or 12 or the cross over points lever 7 being pulled or by
the slide H being pushed back to its normal position, the re-setting being effected
by pushing back the spring 20, either by a tooth of the ratchet W, Fig. 21, or by
the finger 29' as the case may be and so unlatching the elbow lever 23 which
is returned to its normal position indicated by dotted lines, Fig. 21, by the
spring 26.
In Fig. 4 the tappets M M' in the locking case 02 are loose tappets not
connected to any lever or slide; but worked by the bevel locks operated by the
cross over road tappet 7 as hereinafter described.
In Figs. 4, 4, the numerals 2 to 12 denote the tappet blades respectively in the
locking cases 00' of the several levers corresponding to the signals and points
bearing the same numbers and controlled by either of the cabins A. B. C. and the
letters KL, KL' designate the special slide tappets employed according to our
invention and operated by the lever and rod connections J from the slides H applied
to the handles Ġ of the electric block signal receiving instruments E E'.
In Figures 6 to 10 the slide H is shown in detail and the pin G' fixed on the
handle G of the electric block signal instrument E E' is shown in a full circle in
the relative position it occupies in the slot in the slide H when at normal (i.e. "line
blocked") line clear," and "train on line" respectively.
In Figures 11 to 14 we show the suspended electric lock P with its two pairs of
magnets the starter tappet 3 and the slide tappet K with a pivoted tumbler 31
which has an incline on its upper surface to enable the tappet K to ride through a
notch P¹ in the electric lock P. This arrangement is duplicated in connection
with the starter tappet 11 and the slide tappet K'. These Figs. 11 to 14 show the
electric lock P in the four positions it occupies. In Fig. 11 the electric lock P is
in its normal position, the starter tappet 3 being locked by the notch in it being
engaged by the electric lock P as shown and the slide tappet K being free, the
slide plate H at this time occupying the position shown in Figs. 6 and 8.
"
In Fig. 12 the starter tappet 3 is locked by the notch in it being engaged by the
electric lock P as shown and the slide tappet K drawn out to the "line clear
position, the slide H occupying the position shown in Fig. 9; the slide tappet K
as it is being drawn out mounts the inclined surface of its tumbler 31 which
normally rests in a slot in the slide tappet as clearly shown in Fig. 4" and so allows
the notch P to engage the slide tappet.
In Fig. 13 the starter tappet 3 is unlocked by the withdrawal of the electric
lock P and the slide tappet K is drawn out to the "train on line " position the
notches in the slide tappet (shown in the plan view Fig. 4B) receiving both the.
electric lock P and the tumbler 31 and allowing the tappet K to fall into
the position indicated by dotted lines, the slide H occupying the position shown
in Fig. 10. The starter tappet 3 being unlocked its lever 3 may now be pulled
over and when this has been done and the lever put back again the electric lock P
falls by gravity into the position shown in Fig. 14 because the act of pulling over
the starter lever 3 breaks the electric lock local circuit by means of the switch as
herein before described and thus frees the electric lock. Fig. 14 also shows the
position the electric lock P assumes automatically in case of failure or breakage
in the electric lock circuit, the starter tappet 3 and slide tappet K being both
locked by the electric lock P which falls by gravity into the position shown thus
entering the notches and locking both tappets.
In Figures 15 to 19 an alternative, arrangement for the tumbler 31 above:
described is shown. In this case we form inclined surfaces 32, 33, on the lower
part of the locking case 03 and a corresponding inclined projection 34 on the

page_text: under side of the slide tappet K so that when the slide H is drawn to the "line
clear" position, Fig. 9, the slide tappet K mounts the incline 32 and rides through
the notch P¹ in the electric lock P, as shown in Fig. 17, and when the slide His
drawn out to the "train on line" position, Fig. 10, the incline 34 on the under side
of the tappet K descends the incline 33 and by the notch 35 engages the electric
lock P, as shown in Fig. 18, until the lock P is withdrawn by the electric current
controlled by the slide H of the cabin in advance.
I
For convenience of description, let it be supposed that a train on the up line is
waiting to enter a block section at cabin A. at which time A's up starting signal 3
is electrically locked by the suspended lock P controlled by the slide Hin
connection with the handle G of the up line electric receiving instrument E in
cabin B.
The electric lock P is also mechanically forced and held in the locked position
as shown in Fig. 4" and other views, by a special mechanical arrangement which
effectually protects the electric lock against atmospheric or other stray currents or
other interference or failure which could result in unlocking.
In the arrangement illustrated by the drawings this mechanical lock is effected
by the solid part of the slide tappet K coming against the side of the electric
lock P and holding it in the notch in the starter tappet 3. When the signalman
in cabin B accepts the "be ready" from cabin A he gives "line clear" by
drawing the slide H in connection with his up line receiving instrument E to the
"line clear" position (Fig. 9) and in so doing partially unlocks his own up line
starting signal 3 by means of the lever and rod connections J which move his slide
tappet K into the positions indicated by Figs. 12 and 17. This movement of
B's slide H to the "line clear" position also moves the handle G of B's block
instrument E to the corresponding "line clear" position as indicated by the pin G¹
in Fig. 9 and the electrical circuit controlled by the said handle operates
A's electric lock P and takes it completely out of the starter tappet 3 thus
allowing A to take off his starting signal 3 and when A pulls his starter lever 3 to
effect this the electric lock local circuit is broken by means of the switch arrange-
ment already described and illustrated by the detail views, Figs. 20 and 21.
"
The signalman in cabin B then sends forward the "be ready" to cabin C, and
when cabin C gives "line clear" he moves his slide H to "line clear and
thereby partially unlocks his own up line starting sigual 3 by the connections J
and by the electric current completely unlocks B's up line starting signal 3, which
had previously been partially unlocked by the action of B giving A "line clear."
When the electric lock P is moved by the current from C out of B's starter
tappet 3 it engages B's slide tappet K but without locking it taking up the position
illustrated by Figs. 12 and 17.
The signalman in cabin A then gives B "train on line" and when B accepts
and pulls his slide H out to the corresponding "train on line" position, Figs. 10
and 18, B cannot then put back his slide H because the electric lock P is then
completely in the notch in his slide tappet K, being held in that position and clear
of B's starter tappet 3 by the electric current from C's cabin.
66
The signalman in cabin B then takes off his starting signal 3, thereby breaking
the electric lock local circuit by means of the switch operated from the starter
lever 3, as already described, so that, when B's starting signal 3 has been put back
to danger," B's electric lock P falls by gravity into the vertical position and
locks both the starter tappet 3 and slide tappet K as shown in Figs. 14 and 18,
until the signalman in cabin B gives C "train on line" and C accepts by drawing
out his slide H to "train on line" and in so doing takes the electric lock P
completely out of B's slide tappet K and puts it completely into his starter
tappet 3, the electric lock circuit being broken and the electric lock P being
mechanically locked and held in the starter as described when B pushes back his
slide H to the normal or "line blocked" position, Figs. 7 and 8.
The signalman in cabin B in the ordinary course therefore cannot take off his
up line starting signal 3 until the lock has been cancelled by the signalman in

page_text: cabin C giving him "line clear" in the manner above described; but in case the
train is not going forward but is to be shunted to the down line or to a refuge
siding, branch or other road it is necessary to cancel the lock, and to avoid the use
of a key or other special appliance we employ according to our invention a
mechanical cancelling arrangement worked from the cross over road signal lever
or refuge siding signal lever or other signal or points lever as the case may be.
This cancelling may be effected in various ways for example as shown in Fig. 4B
by means of a tappet lock 36 for the slide tappet K (and a similar tappet lock 37
for the other slide tappet K¹) which is worked by the up line sidings points
tappet and up to down disc signal tappet 8.
The tappet lock 36 normally lies clear of the electric lock P but if tappet 5 is
pulled out and then put back or if tappet 8 is pulled out the lock 36 is moved so as
to take the electric lock P out of the slide tappet K, which has previously been
drawn out to "train on line" and locked in that position by the electric lock Pas
described, and puts or holds it in the starting tappet 3 thereby allowing B to clear
the section to A.
The return of the slide tappet K to its normal position re-sets the tappet 36 by
means of the projecting incline 38 on the slide tappet K which pushes back the
tappet 36.
In case a train is drawn up and waiting at say the up line home signal 2 while
another train passes over the cross over road out of the section we prevent the
signalman from moving his slide H from the "train on line "position until the up
home signal lever 2 has first been pulled and then put back to "danger." We
effect this by an arrangement of tappet locks illustrated in Fig. 4 which act as
follows-
Pulling over the starting signal lever 3 puts a bevel lock 39 in the up home
signal tappet 2 and cross over road tappet 7 and a square lock 39 into the slide
tappet K. Pulling or putting back the cross over road tappet 7 takes the square
lock 39 out of the slide tappet K which however remains locked by the electric
lock Puntil released by the signalman in the cabin in advance drawing out his
slide H to "line clear." The above mentioned movement of the cross over road
tappet 7 also takes the bevel lock 39 out of the home signal tappet 2 and puts the
bevel lock 39 into the starter tappet 3 which is released by the signalman in the
cabin in advance accepting the train which has passed over the cross over road and
as the starting signal lever 3 is pulled it puts the square lock 39 back into the slide
tappet K and as the starting signal is put back again its tappet 3 mounts and passes.
over the bevel lock without disturbing it or the square lock 39 in the slide.
tappet K. Consequently the signalman in advance is compelled to clear out his
section before the signalman in whose section the train is waiting can forward the
waiting train or any other.
pass
If instead of pulling the cross over road lever 7 to allow a train to
from one.
line to the other the signalman requires to forward the train waiting at the up.
home signal he takes off the home signal 2 and as the lever 2 is pulled and put back
again the movement of the tappet 2 takes the square lock 39 out of the slide
tappet K and puts the bevel lock into the starter tappet 3, and the starter tappet 3
as it is put back mounts and passes over the bevel lock 39 without disturbing it or
the square lock 39 as before described.
In case a train is to be shunted from one line to another we compel the signalman
to block both nes before pulling the cross over road points lever 7, and this we
effect by means of an arrangement in the locking case Of and shown in plan Fig. 4",
in which we have a tappet lock 40 which in the normal position comes against the
solid part of each slide tappet L L' until the said slide tappets L L have been
drawn out to the "train on line" position to indicate to the signalman in both
cabins (in rear and advance) that the line is blocked. When both the slide
tappets L L have been drawn out to the "train on line" position notches 41 in.
them come opposite the tappet locks 40 and the cross over road lever 7 can then be
pulled over.

page_text: When a train has been admitted to a section and shunted say into a siding and a
second tram has been drawn up at the home signal if the signalman requires to send
forward the shunted train first he is enabled to do so by means of the arrangement
illustrated in Fig. 4" in which we have a tappet lock 42 between the siding lever
tappet 5 and the slide tappet L and another tappet lock 44 in connection with the
starter tappet 3 the slide tappet L, the disc signal tappet 4 and the cross over road
points tappet 7. Consequently the siding lever 5 cannot be pulled over until the
slide tappet L has been put to "train on line" and thereby brought the notch 43
opposite the lock 42, and when this has been done the act of pulling the disc signal
lever 4 puts the square lock 44 into the notch 45 in the slide tappet L and so locks
it in the "train on line" position until the square lock 44 has been taken out of
the slide tappet by pulling over the starter tappet 3.
In order to prevent the cross over road points lever 7 being pulled when the
"line clear" position is shown we employ in the locking case 0³ the arrangement
illustrated by Fig. 44 in which loose slide tappets M M' are fitted over the slide
tappets K L, KL₁ respectively and are locked by the electric lock P when the
latter is held electrically by either the cabin in advance or rear; and when the
loose tappet M or M' is locked it locks the additional cross over road tappet 7 by
means of a tappet lock 46; but whenever the tappets M M¹ are free through the
electric lock P being either at normal or "train on line" position then the cross
over road points lever 7 is free to be pulled over so far as this special locking
device Fig. 4 is concerned.
We have throughout for the sake of simplicity and clearness described the
working of our invention chiefly in connection with the up line; but it will be
obvious to any practical man that the arrangement is duplicated for the down line
and the working of the down line home signal 12, starter signal 11, slide
tappets K¹ L', disc signal 10, and siding points lever 9 is substantially identical
with the working of the corresponding up line signal and points levers and
tappets etc.
The bevel or inclined locks which we use, in carrying out part of our invention,
to enable a lever tappet or slide tappet to mount and pass over a lock without
disturbing it, are preferably constructed and arranged substantially according to
the Specification to Letters Patent numbered 10009 dated May 26th 1892 and
granted to the said Alexander Ross and Thomas Wharmby.
The various electrical and mechanical arrangements which we have shown and
described can be applied to all interlocking frames and to other known types of
electrical block instruments.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what we
claim is
1. The combination with the tappet of the starting signal lever or other lever
and a special tappet or tappets operated mechanically by connections from a slide
applied to the handle of the electric block signal instrument, of an electro magnet
suspended lock operated electrically through an electric circuit controlled by the
slide applied to the handle of the electric block signal instrument in the cabin in
advance substantially in the manuer and for the purposes herein described with
reference to the accompanying drawings.
2. The improved combination and arrangement of parts whereby after a signalman
has moved the handle of his block instrument to the "train on line " position he
cannot again give "line clear" until the signal (or signals) has been taken off for
the train to leave the section and the sanie has again been put back to "danger"
and he has received "train on line " from the cabin in advance or the lock has
been cancelled substantially as herein set forth.
3. The combination with an arrangement for electrically and mechanically inter-
locking railway signal and points levers, of a tumbler with inclined surface, or other
inclines or bevel locks to enable a tappet to mount and pass over or through a lock

page_text: without disturbing it substantially in the manner and for the purposes herein
described with reference to the accompanying drawings.
4. The combination with the lever and slide tappets and electro magnet suspended
lock, of the arrangement of tappet locks in connection with the cross over road,
branch or siding points levers for cancelling purposes substantially as herein set
forth, for the purposes specified.
5. The combination with the special slide tappets and the tappets of the cross
over road and siding points levers, of an arrangement of tappet locks whereby the
signalman is prevented from pulling over either of said levers until the slides in
connection with both up and down line electric instruments have been drawn out to
the "Train on line" position so as to block the lines in both directions substantially
as herein set forth.
6. The combination and arrangement of parts constituting a combined electrical
and mechanical switch for the purpose of breaking and closing the electrical lock
local circuit and also in order to prevent the starting signal being released more
than once by the same "Line clear" current from an adjacent cabin substantially
as and for the purposes herein described and as illustrated by the accompanying
drawings.
7. The several combinations and arrangements of parts embodying our improve-
ments substantially as and for the purposes herein described and as illustrated by
the accompanying drawings.
Dated this 29th day of June 1893.
H. B. BARLOW & GILLETT,
17, St. Ann's Square, Manchester, Agents for Applicants.