Improvements in or relating to Railway Signalling and the like.
Year: 1895

page_text: Date of Application, 1st Feb., 1895
Complete Specification Left, 1st Nov., 1895-Accepted, 7th Dec., 1895
PROVISIONAL SPECIFICATION.
Improvements in or relating to Railway Signalling and the like.
We, WILFRID SWANWICK BOULT, Electrical Engineer, of 60 Castle Street,
and CEDRIC RANDAL BOULT, Merchant, of 62 Dale Street, both in Liverpool,
in the County of Lancaster, do hereby declare the nature of this invention to be as
follows:-
This invention is an amplification of our previous inventions for railway signalling
etc., described in our Specification No. 17041 of 1893, and refers to the reversing
of the polarity of the magnetic field required to act on the divided armature or
other receiving apparatus, whether for automatic or non-automatic signalling, and
to the application of our system to automatic block-signalling, an application which
we will now describe.
In this case a set of fixed permanent or electro-magnets on the train actuate a
series of contact makers or switches on the road-bed by releasing catches moved by
oscillating tongues or equivalent placed in the gaps of the divided armatures as
described in our Specification No. 17041 of 1893. The switches when closed short-
circuit certain parts of a continuous electric circuit passing down the line and
through the coils of a number of electromagnets interspaced with permanent
magnets of opposite polarity. The normal position of the switches is such that
the signalling or track electro-magnets controlled by them are fully excited.
As a train passes over a switch it releases the catch and allows the switch to
close a shunt conductor of low resistance, so as to practically short-circuit the
corresponding track electro-magnets and one of two equal and opposing coils on
an electro-magnet for resetting the last (or other) switch previously released by
the passing train.
"
The various groups of magnets for giving signals to the trains may be as follows:-
The distant signal may be composed of a group of permanent magnets always
giving the "Line-clear" signal closely followed by a compound group consisting of
interspaced permanent magnets to give the "Danger" signal and electro-magnets
which when energized overpower the permanent magnets and give the "Line clear
signal. The home-signal magnets may be a compound group as just described for
the distant-signal but not preceded by a permanent group. A short distance
beyond the home-signal magnets may be placed a group of electro-magnets at
the block station. Over these last named magnets the train will be pulled up
when stopped by the home-signal at "Danger." As soon as the blocked section
ahead is clear the train will get the starting signal.
With this system any failure of current or of movement of the switch would act
to block the line.
::
Modifications of details may be made such for example as the use of electrically
worked semaphore arms or other signals on the road-side instead of the track
electro magnets described, or two sets of oppositely acting electro-magnets instead
of the mixed permanent and electro-magnets or the current may be reversed
through the same magnet coils; or the electro-magnets instead of being simply
short-circuited when not to act may be entirely cut out of circuit.
Dated this 1st day of February 1895.
BOULT & WADE,
Agents for the Applicants..

page_text: improvements in or relating to Railway Signalling and the like.
We WILFRID SWANWICK BOULT, of 14 South Parade, Fulham Road, in th
County of London, Electrical Engineer, formerly of 60 Castle Street, Liverpool
in the County of Lancaster and CEDRIC RANDAL BOULT, of 62 Dale Street
Liverpool, in the County of Lancaster, Merchant, 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 is an amplification of our previous inventions for railway signalling
and the like described in the Specifications of our prior Letters Patent No. 17041
of 1893 and No. 11773 of 1894 respectively, and relates to a method of and
apparatus for reversing or altering the polarity of the magnetic field required to
act as described in the aforesaid Specifications on the divided armature or other
equivalent apparatus on the train, whether for automatic or non-automatic signal-
ling, and also to apparatus for automatic block signalling wherein our improved
method of reversing the polarity of a magnetic field is employed.
According to one part of our present invention we employ, to enable the polarity
of the magnetic fields along the track to be reversed, distinct magnets or
equivalents, or distinct sets of magnets of different polarities and so dispose them
in relation to each other that one magnet or set normally overpowers the other
and so determines the polarity of the field, but can be put out of action or
weakened so that the polarity of the field becomes, reversely, that of the other
magnet or set. According to another part of our invention we dispose along the
railway track groups of magnets and automatic switches for the control of current
to certain of the same, a set of these appliances being appropriated to each block
section; the magnets in each group are specially disposed relatively to each other
to enable the polarity of certain of the magnetic fields in the block to be readily
changed by a train passing along the track; moreover the several groups of
magnets can be specially arranged to differentiate the two or more signals such as
the home and distant signals of a block section.
In carrying out this invention in its relation to automatic signalling we employ
permanent magnets or electro-magnets carried by the train to actuate a series of
contact-makers or switches on the road by releasing catches or actuating other
devices through the movement of oscillating tongues or an equivalent therefor
placed in the gaps of divided armatures stationed along the track; these devices
are arranged to operate as described in our aforesaid Specification of Letters
Patent No. 17041 of 1893. The switches are preferably adapted to short-circuit
or to cut out, on the passing of a train, certain parts, in rear of the train, of
a continuous electric circuit laid along the track and including the coils of a
number of electro-magnets which magnets are in company along the railway track
with other magnets of opposite polarity and lesser effective strength of field;
preferably although not necessarily, these other magnets are permanent magnets
and they are hereinafter referred to as such, being a convenient example. The
normal position of the switches is such that the electro-magnets controlled by them
are fully excited and give tbe "Line clear" signal only.
As a train passes over a divided armature the latter effects the release of a catch
and allows a switch to close a shunt circuit of low resistance so as to practically cut 4
out by affording a short-circuit the corresponding track electro-magnets and one of
two equal and opposing coils of an electro-magnet provided for re-setting the last
(or other desired) switch previously released by the passing train.
The various groups of track magnets in a block section may be arranged as
follows. To the "Distant" signal (say) is allotted a group of permanent magnets &
always giving in conjunction with indicating apparatus on the train the "Line

page_text: clear” signal and a compound group consisting of alternated permanent and electro
magnets, the permanent magnets of this group serving to give the "Danger" signal
and the electro-magnets of the same group serving when energised to overpower
the field of opposite polarity from the permanent magnets and give the "Line
clear" signal. These two groups, the simple and the compound, are so placed that
the train passes the simple group before passing the compound group. To the
home-signal are allotted magnets which would be passed over before the train
arrived at the block station and may be a compound group such as we have just
described for the distant signal, but not preceded by a group of permanent magnets.
The train hands will thus always know whether it is a distant or a home signal that
they are receiving, for they receive two signals from the two groups for the former
and one signal from one group for the latter.
A short distance beyond the magnets for the home signal may be placed a group
of electro-magnets at the block station. Over these last-named magnets, the
position of which may be indicated by a post on the road-side, or otherwise, the
train should be pulled up when checked by receiving a "Danger" indication from
the home-signal magnets. As soon as the blocked section ahead (ie. towards which
the train is proceeding) is clear the train will get the starting signal auto-
matically from that section by way of the electro-magnets over which it is stopping.
If the simple group of permanent magnets is placed near the "Home" magnets
instead of the ". Distant," separate "Block" or "Starting" magnets may be
dispensed with, for, warned by the simple group the driver knows that he is close
to the compound group and can pull up over them, to receive a starting signal
therefrom. With this system any failure of current or of movement of the switch
would act to block the line for the reason that the permanent magnets, being of
opposite polarity to the electro-magnets, would, in the absence of current from the
latter, give the "Danger" signal.
Modifications of details may be made in this invention, such as the use of
electrically-worked semaphore arms or other signals on the road-side instead of the
track magnets described, or instead of employing distinct magnets of opposite
polarity the current may be passed through reverse coils on the same cores, or
reversed through the same magnet coils; or the electro-magnet coils instead of
being simply short-circuited when not required to act, may be entirely cut out of
circuit.
The accompanying drawing is a diagram (divided into two portions at the point
marked X in each) showing the arrangement of circuits and apparatus for carrying
out our invention with permanent and electro-magnets as described above alternated
along the track. 1, 2 and 3 are three positions at which are placed similar
switches A, each controlling one block section, a block section in the present example
being the distance between two sets of track magnets b. Bare the pole-pieces or
"T-ends" of a divided armature B2 such as is referred to in the Specification of
our aforesaid prior Letters Patent No. 11773 of 1894; B1 is the oscillating tongue
in the divided armature to which is attached a catch C, which as the tongue B¹
becomes horizontal (as shown in position 3) under the influence of the travelling
magnet M, carried on the train, moves to allow the switch lever A to fall and, for
example, immerse a fork D in mercury in cups E E', the fork D being a conducting
bridge for a gap normally existent as hereinafter explained between the cups E E
Faud G are two opposing coils on one core constituting an electro-magnet H for
opening the switch A, or allowing it to drop as required. The view shown of the
foregoing parts is that of a transverse section of the line at each station. The
track magnets and the rest of the parts are shown as in plan. Electro-magnets are
indicated by pairs of small circles I and permanent magnets by short thick lines J.
The groups of magnets for the various signals are indicated by d h and b for
"Distant," "Home" and "Block" groups of magnets respectively.
The cup E' in each section is included in the circuit of a conductor K which
includes also the electro-magnets in the groups d, h, of the several sections and
both coils F and G of all the electro-magnets H. The cup E.in each section

page_text: forms the terminal of a low-resistance conductor L in series with one coil F of the
electro-magnet H in the preceding block section, preceding being understood to
mean in the direction of the place whence the traffic comes; for example, the
cup E at station 3 is the terminal for the conductor L leading from the electro-
magnet H at station 2. Normally current from a source of current not indicated
in the drawing but connected up to the lead K in any suitable manner flows say in
the direction of the smaller arrows, continuously through the several portions of the
lead K, the cups E' and the electro-magnets of the several groups d, h, b, in all the
blocks, the leads L in all the blocks being normally cut out by reason of
the existence as aforesaid of the gap between each pair of cups E E¹.
Let it first be assumed that the current was thus flowing and next that a train
has just passed from left to right along the system in the direction of the large
arrow. It will automatically have successively closed the gaps between the
cups EE (as shown for instance at station 3) by causing each catch C to release
its switch A and dip its bridge D into the cups E E. Now considering station 3
the current passing through the electro-mugnet H at the preceding station (2) has
under such circumstances two paths K L open to it instead of one (K) as formerly.
The path L is one of low resistance the other leads through the higher resistance
of the coil G at station 2 and all the electro-magnets of the block section between
stations 2 and 1 which are practically cut out by the short circuiting which has
taken place through conductor L to cup E of station 3 whereby their action is
rendered so fceble as to be negligible.
The track permanent magnets between stations 2 and 1 will now because of the
weakening of the alternated electro-magnets I give the danger signal to any train
following in the direction of the larger arrow. At the same time, coil G at
station 2 being weakened the now unbalanced action of the coil F at that station
raises switch A thereat (which had previously been thrown into the position of the
switch A shown at station 3) so that it re-engages with the catch C as shown, and
the track electro-magnets controlled by it, in the section preceding station 1 are
again energised so as to give the "Line clear" signal. Similar actions take place
as the train passes each succeeding switch.
When the train which has passed station 3 reaches the next switch, it will, by a
similar operation to that which has just been described, close circuit from the coil F
of station 3 onward through the conductor L weakening the current through coil G
of that station and thereby causing the unbalanced action of the coil F to raise the
switch A at the aforesaid station 3 and re-engage it with the catch C thereat in
readiness for further operation.
Where the electro-magnets in a block section are to be completely cut out
(instead of merely short circuited) by the tilting of the arm A we combine with
the arm a device of any convenient kind which will operate to break circuit in the
desired part of the lead K immediately after the arm A has completed the circuit
through its bridge D.
As an alternative to causing as described a magnetic field of given polarity to
overpower one of different polarity, and effecting a change of field by destroying
or reducing what is normally the more powerful field we may cause a field of
given polarity to simply neutralize normally, a field of equal and opposite polarity;
in such case a signal will be given, when one field is destroyed whereupon the
remaining field will operate; when both fields exist, no signal will be given.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. In railway signalling apparatus the employment of magnets of opposite
polarity disposed along the track substantially as and for the purpose described.
2. In railway signalling apparatus the employment of permanent and electro-
maguets of opposite polarity disposed along the track substantially as and for the
purpose described.

page_text: 3. In railway signalling apparatus the combination with permanent and electro-
magnets of opposite polarity allotted to each block section of a magnetic device
such as A Hin each block section serving to effect in a preceding section a change
in the magnetic fields substantially as and for the purpose described.
4. In railway signalling-apparatus the combination with permanent and electro-
magnets of opposite polarity allotted to each block section, of a magnetic device
such as A H in each block section serving to effect in a preceding section both a
change in the magnetic fields and a restoration of readjustment of a like device
substantially as and for the purpose described.
5. In railway signalling apparatus such as is claimed in Claim 1 the combination
with the electro-magnets I in a given block section, of a portion of a lead K wherein
the said electro-magnets are in series, a lead such as L normally interrupted,
adapted to short-circuit the said portion of the lead K, and a device whereby the
train completes that short circuit as it leaves the given block section substantially
as and for the purpose described.
6. The combination with railway signalling apparatus such as is claimed in
Claim 5 of an electro-magnet H having opposed series windings F and G which are
in series with the said portion of the lead K and at their point of junction are
connected with the lead L, and a switch lever such as A substantially as and for
the purpose described.
7. The combination with railway signalling-apparatus such as is claimed in
Claims 5 or 6 of a divided armature B 2, its tongue B' and a detent C substantially
as and for the purpose described.
8. In railway signalling apparatus the employment of more than one set of
magnets for the purpose of differentiating between the distant and home signals
substantially as described.
9. Indicating the difference between a home and a distant signal by repeating a
signal or giving successive signals.
10. The combination and arrangement of parts constituting a complete apparatus
for automatic block signalling and operating substantially as described.
Dated this 30th dex of October 1895
W. S. BOULT.
C. R. BOULT.
Boult & Wade,
Agents for the Applicants.
W. S. BOULT.
C. R. BOULT.
Boult & Wade,
Agents for the Applicants.