Improvements in Apparatus for Ensuring Safety on Single Lines of Railway.
Year: 1895

page_text: Date of Application, 14th Sept., 1895-Accepted, 26th Oct., 1895
COMPLETE SPECIFICATION.
Improvements in Apparatus for Ensuring Safety on Single Lines of
Railway.
WC,
SAMUEL TELFORD DUTTON, Civil Engineer, Marl Bank, in the City of
Worcester, and RALPH HENRY CHRISTOPHER NEVILE, of Crown Lea, Malvern,
in the County of Worcester, Civil Engineer, do hereby declare the nature of this
invention and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement
This invention relates to means of ensuring safety on single lines of railway
having stations, which are ordinarily used as electric staff or train tablet stations
during the day, and which are closed during the night or on Sundays, thus
converting one or more consecutive short sections of line into one longer section.
Certain provisions have been made for working in this way in cases where train
tablet instruments are employed. These provisions are as follows:-
Let it be assumed that there are three stations A, B and C, of which A and C
the terminal stations are constantly in use, and B the intermediate station has to
be switched out at certain times so as to convert the 2 sections A-B and B-C
into one continuous section A.-C.
At A and C are provided instruments for exchanging one round (ordinary)
tablet for one square tablet at a time.
At B is provided an instrument, on pressing plungers of which and securing
them, the tablet line wires are disconnected from their respective instruments
at B and connected together forming one line wire from A to C.
In some cases also where, as is generally the case, B is a loop or passing station,
a special interlocking lever is provided whereby the road, having its points
properly set, is locked "straight through so as to constitute a single road and
this lever is secured in position by a key.
"
The plungers of the instrument at B being also pressed in and secured, the
station may then be left.
If then a signalman at A desires to send a train to C, he asks permission to
issue a tablet in the usual way and receives this from C, not from B. Ile takes
from his instrument an ordinary A to B tablet and inserts it in his exchanging
instrument, from which he then takes a special square tablet authorising a driver
to proceed to C.
This, the present method of working, is in some respects defective.
Our invention has for its object to remedy these defects, for which purpose we
provide arrangements which we shall describe referring to the accompanying
drawings illustrating the application of our invention in connection with Tyer's
train tablet apparatus.
Fig. 1 is a diagram illustrating the arrangement of instruments at one of the
terminal stations, A. Fig. 2 illustrates that at the intermediate station B, where
there is a
by-pass and locking lever as shewn in Fig. 3. Referring to Fig. 1,
DE are polarized relays such that their armatures D, E, remain in the position
to which they were last moved by a current passing through their respective
F is a similar relay except that the armature returns to the neutral
position on the cessation of the current which moved it. These armatures carry
insulated contact pieces D, and F, for closing various circuits,
coils.
5 יד י
2

page_text: In conjunction with the relays D and E are the electro magnets M₁ and M₂ and
their soft iron armatures M, and M.; these are shewn as separate magnets but, if
preferred, the armatures M. and M. may be attracted to the pole pieces of the
relays it being intended that the armatures should be attracted and the various
contacts connected therewith respectively made and broken during the time only
during which an electrical current is passing through the relay. The relays D
and E being for the purpose of respectively sending and receiving currents to and
from station B, they may be termed the sending and receiving relays respectively;
as their armatures are retained in position, they preserve a record of the last
current sent in each direction.
T, and T, are 2 contact pieces arranged in the tablet instrument T in such a
way that when, on withdrawal of a tablet, the lower disc of that instrument
is caused to show "tablet out," these contacts are broken, but when, on
re-insertion of the tablet, either at the same or the other end of the section,
the disc falls back, the contacts are again made by an
arm connected with
the disc.
H₁ is a hand key arranged to make contact with the respective ends of a
battery G, whereof the middle is connected to earth or a return wire.
M and Mu are electro magnets with armatures M₁₂ and M The former
carries a contact piece M and the latter a contact piece M18.
16
M₁ is a trigger, so arranged that, on a key K, being inserted in a key hole and
turned inwards to an extent determined by a stop, the armature M₁ is lifted
and held up, M₁, then making contact. When, however, the magnet Mu is
excited the armature M₁, is lifted slightly higher and the trigger M is released;
and, on the magnet M, ceasing to be excited, the armature M₁, falls completely
down, and the contact M₁ is broken. The trigger is not lifted by taking the
key out again. The armature №12 locks the key K, when inserted so that it
cannot be withdrawn (or turned back) except when the magnet M₁, is excited
raising the armature M₁2. K1, 2, 3, are contacts made when the key is inserted in
the keyhole K, and broken when it is withdrawn, the contacts K, and K, being
broken before the key is free of its lock made by armature M12, but K, remaining
made until the key is free of that lock.
L₁ is an indicator showing that an electric current is passing through it and
that the magnet M₁o is excited and the armature M₁, lifted, and consequently that
the key can be withdrawn from the keyhole K. N₁ is a drawer into which one
of the round tablets can be placed, and, when such a tablet is placed in it and
the drawer closed, a contact for a circuit is made. N, is a similar drawer for one
of the square tablets.
In each case, unless a proper tablet is inserted, no circuit is made.
G1, 2, 3, 4 are batteries which, for the sake of clearness, are shown separate but
which are not necessarily so.
.K, is a keyhole and lock on the exchanging instrument which the key above
referred to fits. K,, are contacts which are made when the key is inserted
into K, and turned to an extent determined by a stop.
5
The exchanging instrument is normally locked so that its spindle cannot be
turned, but, by inserting the key into K, and turning it, the instrument is freed,
and the round and square tablets can be exchanged, provided that the electrical
circuits are also correctly made, so that an electro magnet M₁, is excited
attracting its armature M and thereby removing a further lock and allowing the
exchanging instrument to be operated.
In order that, when the square tablets accumulate at one end of the section, they
may easily be exchanged for round ones and the balance adjusted, we provide a
special key which when inserted in the keyhole K, and turned makes a contact O₁
which the ordinary key does not make. Further when the ordinary key has been
inserted in keyhole K, and turned, it cannot be turned back and withdrawn unless
magnet Mig is excited and armature Mg, lifted; but, when the special key is used,
18

page_text: it can be inserted and withdrawn without the exciting of this magnet. P. is a press
button or plunger which, when pressed in, makes two contacts P, and P.
S, is the lever connected with the starting signal at station A. This lever is
normally locked by any known electrical lock, which is released when magnet Mag
is excited and its armature Me, lifted this breaking one contact M₂, and making
another Mas S, and S, are contacts made by the signal lever when in its normal
position. The contact S, is broken as soon as the lever is moved from its normal
position, but S, is maintained until the lever is free of the lock controlled by
magnet Ms, when it is also broken.
When the lever has been pulled past this point and put back, it cannot be again
pulled over until the magnet M is again excited.
At the other terminal station C the arrangements are precisely similar to those
above described at A with the exception of the band key I, and its battery, which
are not necessary there.
Referring to Fig. 2 which represents the arrangements at the intermediate
station B, D, and D₁o are sending relays similar to D Fig. 1.
10
E, and E are receiving relays similar to E, F, is similar to F.
The contacts on the armatures of these relays and the magnets Mag 271 339 34
similar to those in Fig. 1.
M40
45
are
40:43 are electro magnets which when excited lift their respective armatures
and allow keys to be removed. Magnet M armature M, and trigger M, form
an arrangement similar to M14 16 of Fig. 1 but the arinature M carries the
3 contact pieces M,
16° 47° 45'
10, 11, 12, 13 are contacts made when key K, is in the lock to which it belongs and
broken when it is removed.
K, is a similar contact in connection with key K,.
The keys K, and K, fit into different key holes.
In
In the figures, the connections are shewn as they would be in ordinary day
working when all the lines are clear and no tablets are out of the instruments.
this condition the polarised relays D. E. D. E. E₁, D₁o have their armatures all
held over to + and the contacts D, E, 59 5 D. EE14 18 D₁ are all made, the
others being broken.
6
11
10
16
At the station B, having a single loop as shewn in Fig. 3, there is a lever Z
interlocked with the other levers in such a manner that it cannot be pulled over
until the points are set and bolted for the straight through road and, when it is
pulled over, it locks these points in that condition.
It is provided with a double lock having 2 keyholes KK, adapted respectively
for the same keys as are employed for the keyholes K, and K.
This lock is so arranged that, whatever be the position of the lever, there must
be one of the keys in it, and this cannot be withdrawn until the other key is inserted
and the lever is moved.
The apparatus is operated in the following manner:
When a positive current leaves the tablet instrument T by the wire W it passes
through the relay D and magnet M, through the contact M, and contact K, or K
and thence through earth or a return wire to the tablet instrument battery. It
deflects the arinature D₁ to + causing D, to make contacts. It also raises
armature M, breaking contact M, and making contact M. This establishes a
connection between the end of the battery G, and the line wire and at the same
time, by breaking M,, prevents any portion of the current from returning through
the relay E and magnet M. In this way a + current is transmitted to B, leaving
the armature D, at +, but causing no change in the position of the armature E.
Similarly when a + current is received from B by the line wire, it passes
through relay E and magnet M, through contact M, to earth or return wire; the
armature E, is attracted to + whereby contacts E2, 3, are made and the
armature M is lifted whereby the contacts M, and M, are made and M. broken,
and the end of battery G₁ is put in communication through E, and M, with the

page_text: wire W and the tablet instrument T, thus transmitting a + current to this tablet
instrument. Owing to the contact M, being broken, no portion of this current can
return through relay D.
When it is desired to close and switch out station B, the signalman there having
ascertained from the signalmen at A and C that they are ready, requests them
to plunge upon their tablet instruments. This causes the armatures of the
magnets M., and M. to be lifted and the contacts M₁, and M, to be made.
27
16
35
10
The signalman at B then presses his plunger or button P. and, if the relays are
in the proper position and also the contacts T, and T., a circuit is completed from
battery G contacts M, E, E₁ Mas, T,, T, P, through magnet M₁o back to
battery. If a tablet is out on either section, one or other of these contacts will not
be made. When current flows through M, the armature M is attracted and the
key K, is freed from the lock.
This key is removed, and by this action contacts K10, 11, 12, 18 are broken, thus
severing the connections between the line wires and the tablet instruments. This
key is now placed in the keyhole K₁, on lever Z and, on being turned, it releases
this lever and, after the points have been correctly set and bolted, Z is pulled over
thereby preventing the movement of any of the other levers affecting the points.
On the lever being pulled over the key in K is freed and its removal back-locks
the lever Z; the key is now placed in keyhole K, and turned, thereby raising
armature M, and making contacts M18
16 479 48
28
When this is done, a current that may arrive from A. along line wire will proceed
through receiving relay E7, magnet M, and contact M., to earth. It thus actuates
relay armature Eg in the desired direction and makes contact Ma, breaking M31 ;
a current then flows from one or other end of battery G, through E, or Elo
contacts MM to sending relay D₁, and then through magnet Ma, and contact M.
to earth. Relay Do then sends a current from battery G, by line wire to station C.
Similarly a current from C passes through relay E12 which sends a current to D
which sends one on to A.
30
-
As soon as the signalman at B has inserted the key in K, and turned it and
informed the signalman at A of the fact, the latter moves his hand key II, so as
to make a connection to the side of the battery G3 and there holds it for a
second or two; a current then flows therefrom through contacts T₁, E, relay F,
contact Ms through the special wire to relay F₂ contact M, and on through the
special wire to station C where it goes through a similar relay and contact to that
at A to earth and back to battery G. The relay F3 is not actuated so as to make
a contact but the relay F and the corresponding relay at C do make such
connections, and a current flows from one end of battery G, through contact F₂,
magnet M10 contact K, and back to battery G. Mo when excited raises
armature Miz and makes contact M₁, this completes a branch circuit through
magnet M and indicator L1, so that, when the current through M₁ ceases, which
it does as soon as A. releases hand key H,, the armature M₁, still remains attracted.
The attraction of this armature removes the lock on the key in key hole K. As
previously explained, as soon as the magnet M₁ is excited and the armature M₁, is
attracted, the trigger Me is released and therefore, as soon as the hand key H₁ is
released by A, the armature M₁, falls and the contact M₁, is broken.
The indicator L now shows Key clear
or analogous words, and A removes
the key from the keyhole K, thereby breaking contact K3, whereupon the circuit
through M is broken and armature M1 is released and contact M₁ broken.
10
6
19
The key from K, is now put into the keyhole K, on the exchanging instrument
and turned, thereby making contacts K, and K, and it cannot be removed from K,
again until magnet M,, is excited. When it is desired to exchange a round for a
square tablet, the former is put into the appropriate slot and the button or
plunger P, is pressed making contact P, and, if either of the relay armatures Di
or E, are standing on the negative side (as should be the case if a tablet has been
withdrawn either at A or C) and the starting signal lever S, is in its normal
3

page_text: 25
position, a circuit is completed from battery G. through contacts M. S₁ P
magnet M, contact D, or E. back to the battery. Thus the armature MЯ is
lifted and the exchanging instrument spindle is allowed to turn. Thus the
exchanging instrument cannot be used unless, first, a tablet has been duly with-
drawn, and, secondly, the starting signal is at "danger" and locked; the latter
provision prevents a signalman from withdrawing a round tablet, exchanging it for
a square tablet, using this to release the starting signal, and then exchanging it
again for a round tablet to give to the driver.
In the ordinary course of night working A obtains permission to withdraw a
round tablet, he then exchanges it for a square tablet and places the latter in the
drawer N, which he closes; a circuit is thus completed from battery G4 through
contacts K, N2, D3, S2, magnet M₁, back to the battery. The armature M is
lifted and contact M,, is made, thus closing a branch circuit through M₂ and
keeping the lock off lever S, (although the tablet has been removed from N, and
given to the driver) until the lever is pulled over, when contact S, is broken and
the armature M,, falls. Thus, when the lever has been freed it remains free to be
pulled once and once only after the tablet has been removed from its drawer.
If A, instead of exchanging his round for a square tablet, put his round tablet
into N¹ it would not avail as the circuit from this drawer passes through contact K,
which is broken by the withdrawal of the key from K. Similarly in the day time
the square tablet drawer circuit is broken at contact K,. The signalman cannot
leave the key out of both holes as, if he does so, no current from his sending relay
can pass through M, to earth, both contacts K, and K, being broken; consequently
he cannot actuate his sending relay or send any currents to line.
13
2
3
When it is desired to resume day working and to switch in station B, the
signalman there apprises the men at A and C of his readiness and, if the whole
line A-C is clear of trains and no tablets are out, the signalman at C presses his
tablet plunger; this excites magnet M, and lifts armature M, making contact M.;
the signalman at A presses his plunger or press button P, and thus completes a
circuit from battery G₁ through magnet M₁, contacts P₁, T, E, M, back to battery,
thus exciting M, lifting armature M20 and allowing the key to be removed
from K, and replaced in its normal keyhole K. The signalman at A then presses
his tablet plunger and the signalman at C performs a similar operation with his
key. The signalman at A now moves his band key H, so as to send a positive
current along the special wire. This current does not affect the F relays at A
and C but causes the F, relay at B to close the contact F, whereupon the
magnets M, and M, are acted upon in the way previously explained, the lock on K,
is freed and the indicator L, shows it. When A releases H, the armature M
49
43
44
falls and the contacts M 46 47 48 are broken thus stopping the through tablet circuit
between A and C. K, is now removed (whereby contact K₁ is broken and
armature M is released) and inserted in keyhole K The lever Z is unlocked,
the roads are set properly for day working, the lever Z is put back to its normal
position, the key K is withdrawn from K, and inserted in its normal position and
turned, whereby the contacts K10
10 11 12 13 are remade and normal day communi-
cation is restablished between A and B and B and C.
If it be considered desirable, indicating flags can be arranged in connection with
the receiving relays at B, so that the signalman at B can see upon entering the
cabin whether any tablets are out upon the A-C section and need not trouble the
signalmen at A and C until the section is clear.
In some cases, in order to guard against the possibility of A not removing
the key from K to K, after B has been closed and so continuing round tablet
working with the result of an obstruction in traffic, the following modifications can
be adopted. The hand key H, is made to stand on the one side or the other
either for B closed" or "B open." The circuit from H, to T is taken through
a contact piece on the armature M, and if desired also through one on M, so that
every time these armatures are attracted the contact is made. A bell is arranged

page_text: 22
44
in connection with indicator L₁ so that the whole time this indicator shows
"lock off" the bell will ring and the two contacts K, K,, instead of being made
by the key inserted in Ke, are upon the armature M If then A, after B has
been closed, leaves the hand key H₁ in the position
B open
and uses his tablet
plunger or receives a current, a current will be sent to F, and will cause M to
fall again and the tablet circuit to be broken and the bell at B to start ringing, so
that he will at once have to communicate with B and get him to remove K, from
its lock and reinsert it and set his own instrument right. If however A has put
his handle H, to "B closed" the first time a current is received or sent by him on
the tablet instrument, the armature M₁, and corresponding armature at C will fall.
The bells will ring and continue to do so at A and C until the keys have been
removed from the electrical instrument, and they must be inserted into the
exchanging instruments before currents can be sent along the tablet wires.
An indicating arrangement can also be placed at A and C in connection with the
key of so that when this is removed from the electrical instrument it shows
"B closed." When however the key is put back into the electrical instrument it
does not show "B open until the proper current to release key K, at B has
been sent by relay F and subsequently a current has been received through the
receiving relay. This ensures that B is really opened, as, after a current to
release key K, from its keyhole has been sent, the tablet circuit is broken and no
current can be received on the receiving relay until B has inserted key K, in its
normal keyhole K16
The arrangements above described can be applied with slight modifications to
more than one intermediate station, so that, if it were desired to switch out two or
more intermediate stations between two terminal stations assurance might be had
that all the necessary points were duly set and bolted at all the intermediate
stations and the electrical instruments duly switched over before the through
working and issue of special tablets from the terminal stations could commence.
It is usual to provide at one end of such an intermediate station at B, which it
is desired to switch out at night, a special signal for the train when running
through at night on what would by day be the wrong road, and this signal may be
conveniently worked by the lever Z.
The above arrangements are described as adapted to a system such as Tyer's
train tablet system in which the current sent for unlocking the instrument for the
release of a tablet is always of the same sign, whilst the current sent to restore an
instrument to its normal condition after a tablet has been removed from it is of
the opposite sign. The invention is however with suitable modifications applicable
to other systems, such as the electric train staff system, in which, when a succession
of trains are proceeding in the same direction, the currents sent to release the
successive staffs are of different signs.
In such a system provision has to be made for the case in which a train remains
shunted at the station B while other trains run through B. To provide for this
we combine with the system of relays and connections an automatic commutator
at B which, when necessary, can convert currents of the one sign sent from A
to currents of the opposite sign sent to C or A.
or
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we would have it
understood that we make no claim to the electrical tablet or staff instruments
used for controlling traffic on single lines of railway, nor do we claim by
themselves relays, electromagnets, contacts and other appliances herein before
described as employed in connection with tablet or staff instruments, but what we
claim is :-
In combination with the electrical tablet or staff instruments at two extreme
stations and an intermediate station of a single line of railway, relays, electro-
magnets, contacts and electrical connections, levers and keys arranged in such a

page_text: manner that the intermediate station can, when desired, be excluded from the
tablet or staff working, allowing trains to run safely through from the one extreme
station to the other, substantially as described with reference to the accompanying
diagrams.
Dated this 14th day of September 1895
ABEL & IMRAY,
Agents for the Applicants.