IMPROVED MODE OF AND APPARATUS FOR RAILWAY SIGNALLING
Year: 1874

page_text: LETTERS PATENT to Austin Chambers, of. No. 258, Marylebone Road,
in the County of Middlesex, Signal Engineer, for the Invention
Scaled the 4th August 1874, and dated the 12th June 1874.
PROVISIONAL SPECIFICATION left by the said Austin Chambers at the
Office of the Commissioners of Patents, with his Petition, on the
12th June 1874.
I, AUSTIN CHAMBERS, of No. 258, Marylebone Road, in the County
of Middlesex, Signal Engineer, do hereby declare the nature of the
said Invention for "IMPROVED MODE OF AND APPARATUS FOR RAILWAY
SIGNALLING," to be as follows::-
This Invention is designed to supply a simple, efficient, reliable, and
economical system of railway signalling, and to enable railways to be
worked in foggy or misty weather with greater safety than heretofore, and
without the augmentations of staff necessitated when signalling in foggy
weather by the method at present commonly practised. To this end I

page_text: suppress or dispense with the wires or metal rod connexions usually
employed as media of communication between the signalling boxes,
stations, or places; and the semaphores and lamps or other signalling
bodies or objects, and in lieu of actuating or changing the positions of
such signalling bodies or objects by the direct application thereto of
mechanical means. I actuate them pneumatically, that is to say, I
establish communication between the signalling bodies or objects and
the boxes, stations, or places, whence the same are to be operated by
suitable pipes, tubes, or passages, and I effect the necessary movements
or changes of position of the said signalling bodies or objects by changing
the density or pressure of a volume (or volumes) of air or gas contained
in such pipes, tubes, or passages.
In apparatus according to my Invention, the ordinary, or what I will
call the normal, pressure in the pipes, tubes, or:passages is that of the
external atmosphere for the time being, or thereabout, and when this
pressure prevails in the said pipes, tubes, or passages the signalling
bodies or objects are invariably in the positions indicating danger, their
movement into or towards the positions indicating safety or caution
being effected by augmenting or diminishing the pressure; of the air or
gas in the pipes, tubes, or passages. These augmentations or diminu-
tions of pressure are effected as required by pumps, collapsible vessels,
compressors or exhausters, or rarefiers, or apparatus resembling bellows
or gas holders, or governors connected with the signalling levers or
apparatus so as to be actuated for compressing or rarefying the air when
such levers are moved, or in some cases accumulators or reservoirs of
compressed air or gas, or exhausters, or vessels in which a partial
vacuum has been established and is maintained, may be used in con-
junction with the pipes, tubes, or passages communicating with the
signalling bodies or objects as aforesaid, and the temporary augmentations
or diminutions of pressure in the said pipes, tubes, or passages may be
effected by the opening of suitable cocks or ways, establishing communi.
cation with such accumulators or reservoirs of compressed air or gas, or
with the exhausters or rarefiers, as the case may be, so as to admit
compressed air or gas into the pipes, tubes, or passages, or to partially
exhaust therefrom the air or gas they contain.
.
By arranging the apparatus so that at the normal pressure all the
signalling bodies or objects shall be in the position indicating danger as
above described I effectually guard against accident arising from any

page_text: leakage or other defect in the apparatus, inasmuch as any undue
diminution or increase of pressure will tend to move the signalling
bodies or objects into, or will have the effect of allowing them to resume
the position indicating danger, thus preventing the passage of trains
until the defect has been made good.
My Invention is applicable for signalling in various situations, and
may be used with great advantage for working distance signals and
junction signals, as well as for signalling on railways where the traffic
is worked upon what is known as the block system.
It will enable distance signals to be worked with facility at much
greater distances than by the ordinary method of actuating the
semaphores or signals by wires or metal rod connections, thus obviating
the employment in foggy or misty weather of chains of men for com-
municating signals along the line beyond the distance signals, as now
commonly requisite.
In the pipes, tubes, or passages communicating with distance signals
I in some cases provide valves or other means at intervals, whereby the
guard of a train or other official may when necessary (as for example
when a train has passed within a distance signal, and another train is
heard in front, but is not visible) reduce or increase the pressure in the
pipe, tube, or passage leading to the distance and home signals, and
thereby cause the same to assume the positions indicative of danger.
I provide similar arrangements in conjunction with indicators actuated
by the change of pressure in the pipes, tubes, or passages at railway
stations for the use of station masters, platform foremen, and other
officials. In this way my Invention will afford a simple and efficient
check upon the signalmen in the boxes away from the stations, at the
same time giving the officials at either of these places power to alter thic
pressure in the pipes, tubes, or passages in such manner as to allow
the signals to resume the danger position.
My Invention may be advantageously applied at junctions or in other
situations where it is requisite that two or more signalmen acting
independently should move their respective levers before the semaphore
or signalling body or object can be caused to assume the position
indicating safety. For this purpose I provide an orifice or air way in
the cylinder of each pump at the inner side of the piston, so that until

page_text: or arm when the pressure in the air pipe, tube, or passage is
augmented.
The lenses for effecting signals by showing lights of various colours
may be similarly actuated.
It will be obvious that the arrangements for actuating the signalling
objects or bodies pneumatically as above described may be modified to
suit circumstances without departing from the distinctive character of
my Invention.
In some cases for signalling by different colored lights I arrange
within the lantern a swinging bracket carrying a gas or other light
shielded at the sides.
I partition the lantern into separate compartments, onc. for each color
of lense, and arrange the bracket to be moved through a suitable opening
in the partition from one compartment to another, according to the
color of light required to be shewn, such movements being effected by
the changes of pressure in the air pipes, tubes, or passages herein-before
described.
Sometimes instead of the arrangement just described I use a fixed
light in conjunction with moveable glasses or lenses carried by a
swinging arm or bracket arranged to be actuated by the variations in
pressure in the air pipe, tube, or passage as aforesaid,
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Austin Chambers in the Great Seal Patent Office
on the 12th December 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, AUSTIN
CHAMBERS, of No. 258, Marylebone Road, in the County of Middlesex,
Signal Engincer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twelfth day of June, in the year of our
Lord One thousand eight hundred and seventy-four, in the thirty-seventh
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Austin Chambers, Her special license that I,

page_text: In apparatus according to my Invention the ordinary or what I will
call the normal pressure in the pipes, tubes, or passages, is that of the
external atmosphere for the time being, or thereabout, and when this
pressure prevails in the said pipes, tubes, or passages, the signalling
bodies or objects are invariably in the positions indicating danger, their
movement into or towards the positions indicating safety or caution
being effected by augmenting or diminishing the pressure of the air or
gas in the pipes, tubes, or passages as herein-after described.
33
By arranging the apparatus so that at the normal pressure all the
signalling bodies or objects shall be in the position indicating "danger'
as above described, I effectually guard against accident arising from
any leakage or other defect in the apparatus, inasmuch as any undue
diminution or increase of pressure will tend to move the signalling
bodies or objects into or will have the effect of allowing them to resume
the position indicating "danger," thus preventing the passage of trains
until the defect has been made good.
My Invention is applicable for signalling in various situations, and
may be used with great advantage for working distance signals and
junction signals, as well as for signalling. on railways where the traffic is
worked upon what is known as the block system.
It will enable distance signals to be worked with facility at much
greater distances than by the ordinary method of actuating the sema-
phores or signals by wires or metal rod connections, thus obviating the
employment in foggy or misty weather of chains of men for communi-
cating signals along the line beyond the distance signals as now
commonly requisite.
My Invention may also be advantageously applied at junctions or in
other situations where it is requisite that two or more signalmen acting
independently should move their respective levers before the semaphore
b or signalling body or object can be caused to assume the position
indicating safety.
Fig. 1 of the Drawings is an elevation of an ordinary signal post
provided with a semaphore arm and colored lenses combined with
apparatus for actuating the same pneumatically according to my Inven-
5 tion. a is the signal post, the semaphore arm, to which is rigidly
attached the frame 6' carrying the colored glasses, the glass 6² being of
the proper colour to represent that the line is clear, and the glass of

page_text: the color signifying "danger." The arm 6 and frame 6' form together a
lever of the first order, having its fulcrum at 6. The frame 6¹ with its
lenses, which together constitute the shorter arm of the lever, are made
to slightly preponderate over the longer arm b. The frame b' is con-
nected by a rod d to the upper end of a collapsible vessel e, the part e¹
of which is made of india-rubber or flexible material, and the other
parts may be made of metal, so that when the pressure in the pipe
hcrcin-after mentioned does not exceed the normal pressure of the
external atmosphere the vessel e will be collapsed as shewn in Figure 4.
From the fixed lower end of the vessel e a pipe f communicates with
the interior of a collapsible vessel g shewn also in Figs. 2 and 3. The
ower end of the collapsible vessel g is a fixture, its upper end carries a
guide rod 93 (working in guides g³) as also a tube 9 for guiding the rod
or stem it of a weight & connected by a chain & (or equivalent means) to
the shorter arm of the lever i. The upper end of the collapsible
vessel also has connected to it a couple of chains ; passing over
pulleys, carried by the fixed frame g¹, the chains being provided with
weights ².
In Figure 1 the lever and the parts shewn in section in the right
hand portion of the compressing apparatus represent the positions of the
parts when the air or gas in the pipe f has been compressed and has
expanded or opened out the vessel e, raised the rod d and frame b₁, and
lowered the semaphore arm b.
When the pressure in the pipe f does not exceed the pressure of the
external atmosphere the frame 6' with its attachments preponderates a
over the semaphore arm b, thereby retaining the latter in the horizontal
position indicating danger at all times until the pressure in the pipefis
increased, so as to move the parts into the positions shewn in Fig. 1.
g
On drawing the lever i over in the direction of the arrow into the
position indicated by the dotted line (Fig. 1), the weight will be a
instantaneously raised, thus releasing the upper end of the collapsible
vessel which will be gradually drawn up by the weights and chains j
without its being necessary for the operator to keep hold of the lever i,,
as this lever will be retained in the position to which it has been moved
by an ordinary spring catch. To again compress the vessel git is 3
simply necessary for the operator to move the lever i back into the
position shewn in Figure 1 and to leave it locked. The weight ³ will

page_text: gradually close the vessel g. I provide valves or cocks f* at intervals in
the pipe fleading to distance signals, whereby the guard of a train or
other official may when necessary (as for example when a train has
passed within a distance signal, and another train is licard in front but
is not visible) reduce the pressure in the pipe f to that of the external
atmosphere, and thereby cause the signal to assume the horizontal
position indicative of "danger"; f¹ is a pipe leading to the office of the
station master, platform foreman, or other official, wherein is placed an
ordinary U shaped glass water gauge or indicator f, the liquid in which
being actuated by the changes of pressure in the pipe f will afford a
simple and efficient check upon the singnalman in the box containing
the lever ; f is an adjustable valve which may be so adjusted by the
station master or other official as to alter the pressure in the pipef, either
to bring the semaphore arm or signalling body at once to the danger
position, or to cause it to assume that position within any given time by
a gradual leakage of air or gas from the pipe through the valve.
Figure 5 shews a modification of the air compressing apparatus in
which the lower end of the collapsible vessel 9 has attached to it a
frame g' weighted at 9, the upper side of the frame being connected by
a cord or chain j to the lever i.
Figure 6 shews an arrangement in which a fixed inverted cylinder
open at its lower end to the atmosphere, and provided with a piston k¹ is
substituted for the collapsible vessel g. A frame g' is connected to the
piston rod and has a guide rod 9°, the upper end of which may be
connected by a chain or equivalent means to the actuating lever like the
frame g¹, shown in Figure 5; ³ is a guide for the piston rod.
Figures 7, 8, and 9, shew my Invention as applied for operating
signals at a junction and on a line of railway intended to be worked
according to what is known as the "block" system.
For clearness the signal posts with the parts they carry are (in
Figure 7), shewn twisted round at right angles to their actual position,
which is correctly, shewn in Figure 8. In this case there are supposed
to be three distinct stations A, B, and C, and at the station C a branch
line (provided with a signal box at D) joins the main line. The
collapsible vessel e of station A communicates by its pipe f with the
cylinder of station A, and with the cylinder k, k, of station B. The
collapsible vessel e of station B communicates by its pipe f with

page_text: the cylinder of station B, and with the cylinder k, k, of station C.
The collapsible vessel e of station C, in like manner communicates with
the cylinder k of station C, and with another oylinder situated at the
next station on the line. The collapsible vessele of the branch signal D*
communicates by its pipe f with the cylinder of the signal
box D and with the cylinder * of station C. Each cylinder is formed
with orifices or air ways 7 communicating with the external atmosphere,
and is accurately fitted with a piston ¹ to which is connected a frame k²,
the lower end of which works in a suitable guide (see Figures 9).
To this frame k² is jointed a link jointed to the arm of a bell-crank
lever i, which is to be provided with a catch rod operating in conjunction
with a notched curved bar.
The apparatus is arranged as already explained, so that when the
normal or atmospheric pressure prevails in any one of the pipes f, the
weight of the corresponding arm & with its attachments preponderates
over the semaphore arm b, which is thereby kept in the horizontal or
"danger" position, the collapsible vessel e being collapsed, as shewn at
stations A and B.
In Figures 7 and 8 the signal arms and their operating apparatus are
shewn in the positions they would respectively occupy, assuming that
one train (No. 1) were about to start from the branch line on to the
main line at station C in the direction of the arrow, a second train
(No. 2) being detained at station B until the lever i of the com-
pressor k, k, at station C has been drawn over, and a third train (No. 3)
being detained at station A until the lever i of the compressor k, k, at
station B has been drawn over. The signal D however will not be in
a position for train No. 1 to start until the lever of the compressor k in
the signal box D is pulled over. It is to be understood that at station C
the lever i of the compressor /* and the lever i of the compressor k, k,
are provided with interlocking apparatus of any of the well-known con-
structions at present in use, so that the lever of the compressor k, k,
cannot be moved into the "safety" position until the lever i of the
compressor * has been returned to the "danger" position.
о
In lieu of the orifices or airways 7, above described, taps or cocks
may be arranged to be opened and closed, as required, by the movements
of the signalling levers.
Figures 10, 11, 12, and 13 shew arrangements for carrying out my
Invention by the employment of accumulators or reservoirs of com-

page_text: pressed air or gas. In Figures 10 and 11 two forms of accumulator are
shewn, the one & being made of metal like an ordinary gas holder, scaled
with water, and the other * being a flexible collapsible vessel resembling
those previously described, but of much larger dimensions; but I do not
confine myself to either of these forms, as it will be evident that other
kinds of accumulators may be used in carrying out this part of my
Invention. o is an ordinary air pump worked by the lever o' for sup-
plying air to the accumulators by the pipes f¹; f" is an ordinary
three-way cock, so arranged that when' communication'is established
between the pump o and the accumulator / communication between the
pump and the other accumulator /* is closed, and vice versa; f 18 aro
pipes leading to the several signals. At each of the several signalling
stations with which these pipes respectively communicate they are pro-
vided with a branch pipe f, terminating in a port f20, (Figs. 12 and 13)
provided with a valve n connected by a rod n' to the operating lever i. The
valve n also governs the port f" communicating with the pipe f, which
leads to the actuating apparatus of the semaphore arm or signalling
object. The valve n is made sufficiently heavy to resist the pressure of
air or gas in the pipe ƒ".
121
Figure 12 shews the port f" uncovered, so that as the pressure of the
external atmosphere prevails in the pipe f the semaphore arm or sig-
nalling object is in the "danger" position. By moving over the lever i
in the direction indicated by the arrow the valve n will establish com-
munication between the port ƒ" and the port f, thus admitting air or
gas under pressure into the pipe f, and moving the semaphore arm
or signalling object into the position indicating that a train may proceed.
Instead of employing accumulators or reservoirs of compressed air or
gas, as above described, I in some cases use in conjunction with my
apparatus for governing the movements of semaphore arms or signalling
bodies exhausters or vessels in which a partial vacuum or reduced
pressure has been established, and is maintained. In carrying out this
plan I arrange the pipes f" (Figure 12) in communication with an air-
tight tank or vessel provided with a pump or apparatus arranged to
withdraw air from the tank or vessel, so as to maintain therein the
required partial vacuum or reduced pressure. I apply the rods d at
the opposite sides of the fulcra * to that shewn in Figure 1, and arrange
the apparatus so that when the semaphore arm is in the stop".or
danger" position. the collapsible vessel e or its equivalent. shall be
€6

page_text: 66
expanded or opened out; thus the semaphores will be moved down and
the lenses up, so as to shew the "safety" or pass on" signal by
moving over the lever i (Figure 12), so as by establishing communi-
cation between the pipe f and the pipe f to rarefy or reduce the
pressure of the air or gas in the pipe f.
It will be evident that by a similar modification of the arrangement of
the rod in connecion with the semaphore arm compressors, like that
shewn at g (Figure 1), and others herein-before described, may be
arranged to move down the semaphores and move up the lenses, so as
to indicate" safety" by rarefying or reducing the pressure of the air
or gas in the pipes fon moving over tho actuating levers.
In some cases, in lieu of using moveable lenses, I adapt my Invention
to effect the necessary signals by changing the position of a gas or othor
flame arranged to operate in conjunction with stationary glasses or
lenses. Figures 14, 15, and 16 shew an arrangement for this purpose.
The light is carried by a swinging arm or bracket p.
The lamp is divided into two compartments c³, c, in the present case
by a vertical division c³ slotted at c¹, and the burner carries two small
plates or shutters c¹³, c¹³, for closing the slot c¹ to prevent light passing
from one compartment of the lamp to the other. The collapsible vessel e
has connected to it one end of a cord or chain p', which passes over a
couple of pulleys p²; p³, and at its other end carries a weight p². This
cord or chain is attached to the swinging bracket so that when the
collapsible vessel e is expanded, as shewn, the weight p moves the
bracket into position for shewing the light through the "safety "lens c³,
and when the collapsible vessel e is collapsed its end of the cord or
chain p¹ is drawn down, thus moving the bracket and burner into
position for shewing the light through the "danger "lens c³. The Drawing
shews a burner designed to carry a candle, but it will be evident that
brackets carrying oil or other burners may be substituted for the candle
arrangement shewn, or the bracket may carry a gas burner fed by a
flexible tube; or, in lieu of the bracket shewn, an ordinary swinging gas
bracket may be substituted therefor, so as to be operated in the manner
shewn in and described with reference to Figures 14, 15, and 16. It will
be evident that in lieu of the collapsible vessel e shewn in these Figures
other forms of collapsible vessels may be used in conjunction with the
swinging bracket and divided lamp so as to be operated by changing the
pressure of air or gas as and for the purpose specified.

page_text: Having described the nature of my said invention, and having
explained the manner of carrying the same into practical effect, I hereby
declare that I do not claim pneumatic signalling generally, apart from
the objects and purposes of my Invention, as I am aware that signals
have been proposed to be actuated by changing the pressure of elastic
of
fluids in pipes; nor do I claim as of my Invention or the exclusive use
the several mechanical parts herein-before described or referred to,
except when the same are used in and for the purposes of my Invention,
which I hereby declare to consist in,-
First. The combination of parts forming the improved pneumatic
signalling apparatus for railways, constructed and operating substantially
as shown in and described with reference to Figures 1, 2, 3, and 4 of the
Drawings.
.
Secondly. The apparatus shewn in Figure 5, when applied in
conjunction with a pipe, tube, or passage, charged with air or gas, and a
collapsible vessel or chamber to operate a semaphore arm or lever for
signalling on railways, as herein-before described.
Thirdly. The apparatus shown in Fgure 6 when applied in conjunction
with a pipe, tube, or passage, and a collapsible vessel or chamber to
operate a semaphore arm or lever for signalling on railways, as
hercin-before described.
Fourthly. So combining two or more distinct pumps or compressors, and
suitable actuating levers or handles with a single semaphore arm, or with
a single set of bodies (such for example as a semaphore lever and its
lenses) for signalling on railways; and a pipe, tube, or passage, charged
with air or gas, as to maintain communication between the interior of
the said pipe, tube, or passage, and the external atmosphere, and so to
prevent the giving of a "safety" or "pass on" signal, until both or all
of the aforesaid actuating levers or handles have been moved into the
proper positions for indicating that a train may proceed.
Fifthly. The arrangement of apparatus substantially as shown in and
described with reference to Figures 7, 8, and 9, for signalling on the
"
'block system and at junctions.
"
Sixthly. The combination with a semaphore arm or equivalent object
or body (with or without lenses and a lamp) for signalling on railways,
of a pipe, tube, or passage, charged with air or gas, a collapsible vessel
.

page_text: or chamber, a reservoir of compressed air or gas, and apparatus operated
by a lever for establishing communication between the reservoir and the
pipe leading to the collapsible vessel, as shewn in and described with
reference to Figures 10, 11, 12, and 13, for the purposes specified.
Seventhly. The combination with a semaphore arm or equivalent
object or body (with or without lenses and a lamp) for signalling on
railways, of a pipe, tube, or passage charged with air or gas, a
collapsible vessel or chamber, and an exhauster or vessel in which a
partial vacuum or reduced pressure is maintained; such pipe, tube, or
passage being furnished with a suitable cock or device for openingand
closing communication between it and the exhauster or vessel in which
the partial vacuum or reduced pressure is maintained, substantially as
and for the purposes specified.
Eighthly. The application and use in railway signalling apparatus of a
pipe, tube, or passage charged with air or gas, means or apparatus for
changing the pressure thereof, and a collapsible vessel or chamber for
effecting the necessary movements or changes of position, of a light
relatively to fixed glasses or lenses.
Ninthly. The combination of parts constituting an apparatus for
railway signalling constructed and operating as shewn in and described
with reference to Figures 14, 15, and 16 of the Drawings.
In witness whereof, I, the said Austin Chambers, have hereunto set
my hand and seal, this Twelfth day of December, in the year of
Our Lord One thousand eight hundred and seventy-four.