Improvements in Railway Signalling Systems.
Year: 1894

page_text: Date of Application, 30th Oct., 1894-Accepted, 29th Dec., 1894
COMPLETE SPECIFICATION.
Improvements in Railway Signalling Systems.
I, WILLIAM PHILLIPS HALL, of No. 80 Broadway, New York City, in the
County and State of New York, United States of America, President of The
Hall Signal 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:-
This invention relates to automatic electric railway signals for block systems and
has for its object to improve and render more certain the operation thereof, thus
reducing the liability of false signals, and also to provide for an increase in
the present length of the blocks beyond which it is now not practicable to
operate the signals. It consists of the devices and their arrangement hereinafter
set forth.
In systems of this class it has. been usual to divide the track into a series of
blocks, locating a signal near the beginning of each block, and to control these
signals by means of signal circuits operated by circuits which include the rails of
the track. These blocks have generally been not more than one mile in length and
the rails which form part of the circuit of each block have been laid directly
upon the cross ties and without the intervention of any insulation. As the train
advanced upon the block it operated the signal by bridging the rails and thus
shunting the battery from the magnet included in circuit with the rails, thus
breaking the signal circuit. It is of course apparent that anything that might
break the rail circuits or connect the rails of a block would necessarily operate the
signal. Ordinarily the track battery of each section finds the normally closed
metallic circuit through the rails of so much less resistance than that offered by the
cross-ties that mechanically bridge the rails, or than that offered by the gravel,
stone, ashes or other similar material of which the road bed is generally made, that
there is little possibility of the battery being short circuited through the cross-ties
or roadbed to such a degree that the signal would be thrown to danger. But if
the block is materially increased in length its resistance is likewise increased while
It is
the resistance of the material composing the roadbed remains the same.
therefore obvious that there must be a limit to the length of the track section
which can safely be employed, for, when its resistance approximates that.of the
material of the roadbed lying between the rails the battery is likely to be short
circuited and produce false signals. For this reason it is not usual to employ a
There are cases,
track circuit in systems of this character longer than one mile.
however, where it has been found advantageous to employ blocks two or three
miles in length, or even longer, but the increased resistance of the track circuits
and the consequent liability of short circuits between the rails, and therefore false
signals, has rendered their employment impracticable. Again, it has been found
that the resistance afforded by roadbeds varies considerably in accordance with the
particular material used and with the care with which the road bel may be
constructed. For example, it has been ascertained that a cinder roadbed offers
less resistance than one made of earth, and also that, where perfect drainage is not
provided for, pools of water standing on the track and either bridging the rails or
soaking the cross-ties may provide a short path for the circuit. Moreover it may

page_text: be desirable in some cases to increase the strength of the track battery to such an
extent that a considerable portion of its current may find a short path across the
rails while scarcely enough finds circuit through the signal circuit to render the
operation of the signal certain.
These various objectionable features and limitations of construction are largely
obviated by the present invention, the embodiment of which permits blocks of
considerable length to be employed, and permits this to be accomplished notwith-
standing poor insulation of the roadbed, and permits blocks of ordinary length to
be employed where the condition of the roadbed would prevent efficient operation
with the signalling devices and circuits heretofore employed. The invention also
includes an exceedingly simple and efficient arrangement of circuits and arrange-
ment and construction of other apparatus.
The invention may be carried out by employing either a normally de-energized
signal circuit with the signal preferably normally at danger or by employing a
normally de-energized signal circuit with the signal preferably normally at safety.
In the first case before a train enters a block it energizes the signal circuit and
throws the signal to safety. If, however, there is a train in the block about to be
entered, this train will de-energize the signal circuit at a second point. The
engineer on the first train finding therefore that his train does not put the signal at
safety, knows that a train is somewhere in the block which he is about to enter, and
waits until the signal clears before he enters the block.
By employing a normally de-energized signal circuit a great saving is made in
battery consumption, because the battery or batteries of the signal circuit is
normally inactive and is only in a state of excitation just before a train enters a
clear section. And by employing a signal normally at danger with a normally
open signal circuit any failure of the parts to act when a train approaches a signal
will leave the signal at danger and thus ensure safety. I may employ various means
for maintaining the signal circuit in a de-energized condition, and in the same way
I may employ various means for de-energizing the signal circuit at various points
along the track section. I have, however, shown and shall describe my system as
employing the ordinary means of de-energizing the circuits, viz., a make-and-break
contact, but do not wish to be limited to the use of this particular means.
Figure 1 represents diagrammatically an embodiment of the invention in which
the signal circuit is normally open with the signals normally at danger and
Figure 2 represents diagrammatically an embodiment of the invention in which
the signal circuit is normally closed with the signals normally at safety.
Referring now to Fig. 1, one complete block of the railway is shown in the
drawings extending from the signal S to a point beyond the signal S₁ so as to make
an overlap of a block upon the succeeding block. Portions of the preceding and
succeeding blocks are also shown. Thus the section of track guarded by the
signal S includes the entire block intervening between the signals S and S' (divided
into sub-sections 1, 2, 3, 4) and a sub-section (1) of the next block. A' designates
this guarded block, A the portions shown of the preceding guarded block, and
A³ the portions shown of the succeeding guarded block. Each signalling block
may be divided into any convenient number of sub-sections, and the overlap may
include any desired number of sub-sections. The track sub-sections in each block
shown are designated 1, 2, 3 and 4 and 1. Each sub-section of the track is
provided at its inner or exit end with a battery m and at its outer or entering end
with a bridge circuit including a magnet, said magnets being lettered respectively d, a',
b, c, d, a. The signal is located at the outer end of each guarded block.
Extending along the track is the line wire f, to which are connected the wires g.g',g³,
of guarded blocks A, A', A', respectively. The wire g¹ connects with at the
points and ', and extends through the normally open circuit breaker 6
(controlled by electro-magnet d) and through the normally closed circuit
breakers 1, 2, 31, 4' and 5 (controlled respectively by electro-magnets a, b, c, d¹
and a) and extends to the signal S. At the signal S this circuit acts directly or
through intervening mechanism and circuits to put the signal at clear when a

page_text: current flows through the circuit f, g'. The circuit /g' includes at some convenient
point a source of energy here shown as a battery B', which supplies current to the
circuit. To the wire f is connected at a circuit wire g³, belonging to the
block A. The wire 9 extends through a second circuit breaker 9 (normally open)
controlled by the electro-magnet d', and through a second circuit breaker 10
(normally closed) controlled by the electro-magnet a², then to the signal S¹ and
thence through the several circuit-breakers of the sub-sections and through the
battery of the guarded block A' and back to wire fin exactly the same way as the
wire g'. At the point is connected a circuit wire g, belonging to the block A,
which passes through the battery B, the two normally closed circuit breakers 8
and 7, the circuit breaker 8 being controlled by the electro-magnet a¹, and the
circuit breaker 7 being controlled by the electro-magnet d. Thence the circuit
wire passes through the magnets and signal mechanism of the block A. The
circuit fg being operated to hold its signal to danger after the signal circuit f g¹ is
operated to put its signal to danger so that the train is protected by a danger
indication of the signal S before the protection of the preceding signal is withdrawn,
it is thus seen that these circuits overlap. In the same way it will be seen that the
circuits fg and fy' overlap.
The operation is as follows:- -The signals being normally at danger, as a train
enters sub-section 4 of the block preceding the signal S and of the guarded block A
it shunts battery m from the magnet d and breaks the circuit f, g, at 7, and closes
the circuit f, g, at 6. The break at 7 continues while any part of the train is on
the sub-section 4, and retains the signal of block A at danger (or in other words
prevents it from going to clear in front of an approaching train) as will hereinafter
appear. The completion of circuit f, g¹ at 6 operates the signal S of block A¹ and
throws it to safety, the circuit passing from point, through circuit breaker 6,
circuit breaker 1', signal S, circuit breakers 21, 31, 41, 5, battery B₁ and through
wire, back to point r As the train passes onto sub-section 1 of the guarded
block A, it again breaks the circuit f, g, this time at 8, and also breaks the
circuit f, gat.1', returning signal S to danger. When the train has passed
entirely off sub-section 1, the circuit f, g, will be closed at 8 and restored to its
normal condition. As the train advances upon the succeeding sub-sections of
block A¹ it operates the magnets ₁, c¹, d' and a², successively, and breaks the
circuit f, g at these points. As the train enters sub-section 4 it not only breaks the
circuit, g', but also closes the circuit, g' at 9, which, through its battery, not
shown, throws the signal S' to safety. From this description of the operation it is
obvious that just before entering the guarded block A' and passing its signal S, a
train will complete the normal break in the circuit of said block A' at 6 and that,
if the circuit is not broken at 11, 21, 31, 4 or 5 by the presence of a train on this
block, the signal will be moved to safety; and that if a train is already in block A¹
the signal S can not be thrown to safety although the circuit may be closed at 6.
It is also obvious that as soon as the train enters the sub-section 1 and as long as it
is in the block, it breaks the circuit f, g' and prevents signal S from being thrown
to safety by a succeeding train. Thus a train always has a block including its
overlaps clear to itself, and danger of collision is avoided.
Referring now to Figure 2, A' designates one block of the track and is provided
with the wire circuits, signals, etc. hereinafter fully set forth. A is the preceding
block, and A? is the block following block A'. The rails of block A' are divided into
any convenient number of sub-sections, here shown as five in number, and the end
sub-sections, viz. 1 and 5, are common to blocks A' and A, and to blocks A' and A³,
respectively, thus making an overlap for each block. Each sub-section of the track is
provided with a battery m, and at its outer, or entering, end with a bridge circuit,
including a magnet, lettered respectively a, b, c, d and e. Each of the blocks is guarded
by its signal S, S', &c., located at its outer end, and, therefore, at the beginning of
the overlap. That entire portion of the track which is guarded by any one signal
is what is called a block. Extending along the track is a wire g, to which
is connected a wire y₁ at points and k, opposite, or approximately opposite,

page_text: respectively the outer and inner ends of section A'. This wire g¹ extends from
point through circuit breakers 1, 2, 3, 4 and 5¹ controlled respectively by
magnets a, b, c, d and e. but passing to the operating devices of signal S between
the circuit breakers 1 and 21. The circuit g, g' includes at some convenient point.
a battery B', which serves to hold the signal operating devices in their normal
position and the signal at safety. To the wire g is connected at a circuit wire p
belonging to section A* which passes through a second circuit breaker ', controlled
by the magnet e, then to the operating devices of signal S', thence through the
circuit controllers of the track magnets and the battery of section A² back to
wire g in the same way as wire g'. At the point k is connected a circuit wire o
belonging to section A, which passes through battery B, circuit breaker h, controlled
by magnet a, and thence through the circuit controller of the track magnet, the
battery and signal mechanism of the section A back to wire g. Thus it will be
seen that a portion of any two adjoining blocks is arranged to operate both the
signal circuits for those blocks at the same time, so that when a train is upon this
portion of the track common to the two blocks, it operates the signals of both
blocks simultaneously.
The operation is as follows: A train entering overlapping sub-section 1 shunts
battery m from magnet a, breaks the circuits at and 1', and throws to danger the
signal of block A and signal S of block A¹. As it passes off the sub-section 1,
circuit breaker his restored to normal, and the signal of block A returns to safety.
The circuit breaker 11 at the same time returns to normal, but before the train has
passed entirely from sub-section 1 it has entered upon sub-section 2, and broken
the circuit at 21, and before it has restored the circuit at 2¹ it has broken it again
at 3', and so on throughout the block. When the train enters sub-section 5 it not
only breaks again its signal circuit g g' at 5' holding signal S at danger until it has
passed off overlapping sub-section 5, but also breaks the circuit of signal S₁ at '.
Thus signal S is maintained at danger from the moment the train enters block A¹
till it has passed entirely off the block and, at the same time, the train throws the
signal S¹ to danger when it enters the overlap of block A² and before it has left
section A¹.
By introducing into each signal circuit as thus set forth a number of circuit
breakers, each controlled by a comparatively short track circuit it is obvious
that the length of a block may be indefinitely increased, whatever may be the
character of the roadbed, without endangering in any degree the certainty of
operation of the system. It is also obvious that inasmuch as the track circuits may
be shortened to any degree, whatever may be the length of the block, the
batteries m will always find ready circuit through their magnets and maintain the
signal circuit intact. In fine, whatever may be the condition of a roadbed and its
liability to shunt a track battery or whatever may be the strength of a track
battery or the length of a signal block desired, this system may be adjusted to meet
fully the requirements of each case.
This invention is not confined to any particular character of signal or signal
operating mechanism, as they of course may be varied at will. Various other
changes may be made without departing from the broad invention. For instance,
the track circuits for each sub-section need not necessarily include the rails of the
track, but the train may operate these track circuits by means of track instruments.
Moreover, although the drawings have shown permanently unbroken track circuits
adapted to be shunted but never broken, this invention is not to be limited to a
circuit of this form. Again the means for operating the signal circuit through
the track circuits may be widely varied. The wires and g need not be general
circuit wires extending continuously along the track, but may be coterminous
each with its block and the overlapping feature need not necessarily be employed.
The drawings show the overlap of each block covering one sub-section, but it
may cover more than one or may be omitted altogether if desired. Various other
changes may also be readily suggested.
The term 'track-section in the claims is of broader significance than the term

page_text: 'block' and, when taken by itself, may include more or less sub-sections than a
block is defined to include.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
1. In an electric signalling system for railways, the combination of a block of a
track divided into two or more sub-sections, a track circuit for each sub-section, a
normally de-energized signal circuit, means preceding said block for energizing
the signal circuit by sending a current therethrough to operate the signal, and
means included in said signal circuit for de-energizing it upon a change in the
electric condition of each of the track circuits of the block, substantially as
set forth.
2. In an electric signalling system for railways, the combination of a block of a
track divided into two or more sub-sections, a permanently unbroken track circuit
for each sub-section, a normally de-energized signal circuit and a signal normally
at danger, means preceding said block for energizing the signal circuit by sending
a current therethrough to operate the signal, and means included in said signal
circuit for de-energizing it upon a change in the electric condition of each of the
track circuits of the block, substantially as set forth.
3. In an electric signalling system for railways, the combination of a block of a
track divided into two or more sub-sections, a track circuit including the rails of the
track for each sub-section, a normally de-energized signal circuit, means preceding
said block for energizing the signal circuit by sending a current therethrough to
operate the signal, and means included in said signal circuit for de-energizing it
upon a change in the electric condition of each of the track circuits of the block,
substantially as set forth.
4. In an electric signalling system for railways, the combination of a block. of a
track divided into two or more sub-sections, a permanently unbroken track circuit
including the rails of the track for each sub-section, a normally de-energized signal
circuit, a signal normally at danger, means preceding said block for energizing the
signal circuit by sending a current therethrough to operate the signal, and means
included in said signal circuit for de-energizing it upon a change in the electric
condition of each of the track circuits of the block, substantially as set forth.
5. In an electric signalling system for railways, the combination of a track
divided into series of blocks, each divided into sub-sections, a track circuit for each
sub-section, a normally de-energized signal circuit for each, block adapted to operate
a signal near the entrance thereof, each block and each signal circuit overlapping,
respectively, the succeeding block and signal circuit, means included in each signal
circuit for sending a current therethrough to energize it upon a change in the
electric condition of a track circuit of the preceding block, and means included in
each signal circuit for de-energizing it upon a change in the electric condition of
each of the succeeding track circuits of its block, substantially as and for the
purpose set forth.
6. In an electric signalling system for railways, the combination of a block of a
track divided into two or more sub-sections, a track circuit for each sub-section, a
normally open signal circuit, means preceding said block for closing the signal
circuit to operate the signal, and means included in the signal circuit for breaking
it upon a change in the electric condition of each of the track circuits of the block,
substantially as set forth.
7. In an electric signalling system for railways, the combination of a block of a
track divided into two or more sub-sections, a track circuit including the rails of
the track for each sub-section, a normally open signal circuit, means preceding
said block for closing the signal circuit to operate the signal, and means included in
the signal circuit for breaking it upon a change in the electric condition of each of
5 the track circuits of the block, substantially as set forth.
8. In an electric signalling system for railways, the combination of a track

page_text: section divided into two or more sub-sections, a track circuit for each sub-section,
a normally open signal circuit, one side of which comprises a wire extending
continuously along the track and the other side of which joins the first mentioned
side near the ends of the section, means for closing the signal circuit upon a change
in the electric condition of one of the track circuits of the section, and means for
breaking the signal circuit upon a change in the electric condition of one or more
of the track circuits, substantially as and for the purpose set forth.
9. In an electric signalling system for railways, the combination of a track
divided into a series of blocks, each divided into sub-sections, a track circuit
for each sub-section, a normally open signal circuit for each block adapted to
operate a signal near the entrance thereof, each block and each signal circuit
overlapping, respectively, the succeeding block and signal circuit, means included
in each signal circuit for closing it upon a change in the electric condition of a
track circuit of the preceding block, and means included in each signal circuit
for breaking it upon a change in the electric condition of each of the track
circuits of its block, substantially as and for the purpose set forth.
10. In an electric signalling system for railways, the combination of a track
divided into a series of blocks, each divided into sub-sections, one or more sub-
sections at the inner end of each block constituting one ог more sub-sections
at the outer end of the succeeding block, a normally closed track circuit for
each sub-section, a normally open signal circuit for each block adapted to
operate a signal near the entrance thereof and overlapping the signal circuit
of the succeeding block, means for closing the signal circuit upon a change in
the electric condition of a track circuit of a preceding block, and means for
breaking the signal circuit upon a change in the electric condition of each of
the succeeding track circuits of its block, substantially as and for the purpose set
forth.
11. In an electric signalling system for railways, the combination of a track
divided into a series of blocks, each divided into sub-sections, a normally closed
track circuit including the rails of the track for each sub-section, a normally open
signal circuit for each block, means for closing the signal circuit upon a change
in the electric condition of a track circuit of a preceding block to operate the
signal, and means for breaking the signal circuit upon a change in the electric
condition of each of the succeeding track circuits of its block, substantially as
and for the purpose set forth.
12. In an electric signalling system for railways, the combination of a track
divided into a series of blocks, each divided into sub-sections, the last one or
more sub-sections of each block constituting the first one or more sub-sections of
the succeeding block, a normally closed track circuit for each sub-section
including the rails of the track and a magnet, a signal circuit for each block
including circuit-controllers, each controlled by the magnet of a track circuit,
the signal circuit being normally open at the circuit-controller of the first
magnet but normally closed at the circuit controllers of the other magnets, the
magnets of the last one or more track circuits of each block respectively
controlling also the first one or more armatures of the signal circuit of the
succeeding block, substantially as and for the purpose set forth.
13. In an electric signalling system for railways, the combination of a block
divided into sub-sections, a permanently unbroken track circuit for each sub-
section, a signal, a separate track circuit preceding said block, a normally open
signalling circuit extending approximately from the outer to the inner end of the
block and connected to said signal, said sigualling circuit containing a series of
normally closed circuit breakers each operated by a change in condition of one
of the track circuits, and a normally open circuit breaker operated by a change
in the condition of the track circuit preceding said block, substantially as set forth.
14. In an electric signalling system for railways, the combination of a block
divided into sub-sections, a normally closed track circuit including the rails of
the track for each sub-section, a signal, a separate track circuit including the

page_text: rails of the track preceding said block, a normally open signalling circuit
extending approximately from the outer to the inner end of said block and
connected to said signal, said signalling circuit containing a series of normally
closed circuit breakers, each operated by a change in the condition of one of
the track circuits of the block, and a normally open circuit breaker operated
by a change in condition of the rail circuit preceding said block, substantially
as set forth.
15. In an electric signalling system for railways, the combination of a track
divided into a series of blocks each divided into sub-sections, a track circuit for
each sub-section including the rails of the track and an electro-magnet, the inner
sub-section of one block corresponding with the outer sub-section of the adjoining
block, a signal for each block, a signal circuit for each block connected to said
signal and including normally closed circuit breakers, each controlled by an
electro-magnet of one of the track circuits of the block, the electro-magnet of
the overlap controlling two of said circuit breakers, one in each signalling circuit,
and also including a normally open circuit breaker controlled by the electro-
magnet of the sub-section of a preceding block, substantially as set forth.
16. In an electric signalling system for railways, the combination of a track
divided into a series of blocks, each divided into sub-sections, a normally closed
track circuit for each sub-section including an electro-magnet, a portion of the
inner end of each block constituting a portion of the outer end of the succeeding
block, a signal circuit for each block, one side of which comprises a portion of a
wire extending continuously along the track and the other side of which
comprises a loop, joining at one of its ends the first mentioned side of the
circuit near the inner end of the block, and at its other end joining the said
first mentioned side at a point within the exit end of the preceding block, the
loop side of said signal circuit including normally closed circuit breakers, each
of which is controlled by the electro-magnet of a track circuit of the block and
another circuit breaker normally open and controlled by the magnet of a track
circuit of the preceding block, the magnets which control the two circuit
breakers at the inner end of a block also controlling the first two circuit
breakers at the outer end of the succeeding section, substantially as set forth.
17. In an electric block signalling system, the combination of a block or section
including a series of three or more sub-sections independent of each other, a series
of three or more track circuits independent of each other, one for each sub-
section, a signal circuit for the block or section, including a series of three or
more circuit controllers independent of each other, each one of the said track
circuits operating independently of the said circuit controllers of the signal circuit
and a signal operated by the signal circuit located near the beginning of the block
or section, substantially as set forth.
one
18. In an electric block signalling system, the combination of a block or section
including a series of three or more sub-sections independent of each other, a
series of three or more track circuits independent of each other,
for each sub-section, a signal circuit for the block or section, including
a series of three or more circuit controllers independent of each other, each one
of the said track circuits operating directly and independently one of the said
circuit controllers of the signal circuit and a signal operated by each signal
circuit located near the beginning of the block or section, substantially as set
forth.
19. In an electric block signalling system, the combination of a series of two or
more blocks or sections, each block or section including three or more independent
sub-sections, a series of independent track circuits, one for each sub-section, a
series of signal circuits one for each block or section, each signal circuit including
a series of three or more independent circuit controllers, each one of the track
circuits operating one of the said circuit controllers, and a series of signals
operated one by cach signal circuit located near the beginning of the corre-

page_text: sponding block or section, each block or section overlapping the adjacent block
or section and each signal circuit overlapping the adjacent signal circuit,
substantially as and for the purpose set forth.
20. In an electric signalling system for railways, the combination of a series of
blocks, each divided into sub-sections, a track circuit for each sub-section, a
series of signal circuits corresponding to the blocks and each adapted to be
operated upon a change in the electric condition of each of its track circuits,
each block overlapping the succeeding block and each signal circuit overlapping
the succeeding signal circuit, substantially as and for the purpose set forth.
21. In an electric signalling system for railways, the combination of a series
of blocks, each divided into sub-sections, a track circuit for each sub-section, an
overlapping signal circuit for each block adapted to be operated upon a change
in the electric condition of each of its track circuits, the inner sub-section of a
block being also the outer sub-section of the succeeding block, substantially as
and for the purpose set forth.
22. In an electric signalling system for railways, the combination of a series of
blocks, each divided into sub-sections, a track circuit for each sub-section, an
overlapping signal circuit for each block adapted to be operated upon a change
in the electric condition of each of its track circuits, the inner sub-section of a
block being also the outer sub-section of the succeeding block, the inner end of
one side of a signal circuit being also the outer end of one side of the
succeeding signal circuit, substantially as and for the purpose set forth.
23. In an electric signalling system for railways, the combination of a series of
blocks, each divided into a series of sub-sections, the inner sub-section of each
block being also the outer sub-section of the succeeding block, a normally closed
track circuit for each sub-section, an overlapping signal circuit for each block
adapted to be operated upon a change in the electric condition of the track
circuits, substantially as and for the purpose set forth.
24. In an electric signalling system for railways, the combination of a series of
blocks, each divided into a series of sub-sections, the inner sub-section of each
block being also the outer sub-section of the succeeding block, a normally closed
track circuit for each sub-section, an overlapping signal circuit for each block,
provided with normally closed circuit breakers each adapted to be opened upon
a decrease in the electric tension of each of its track circuits whereby a train
entering upon a block will throw the signal to danger and retain it there until it
has passed entirely off the overlap of the succeeding block, substantially as and
for the purpose set forth.
25. In an electric signalling system for railways, the combination of a series of
blocks, each divided into a series of sub-sections, the inner sub-section of each block
being also the outer sub-section of the succeeding block, signal circuits; one side of
which extends continuously along the track and the other side of which extends
approximately from end to end of the block, a series of normally closed circuit-
breakers in each signal circuit, a normally closed track circuit for each sub-
section including the rails thereof, and magnets for operating the circuit breaker
upon a decrease in the tension of said track circuit, substantially as and for the
purpose set forth.
Dated this 30th day of October 1894.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant..