IMPROVEMENTS IN WORKING ATMO- SPHERIC RAILWAYS
Year: 1844

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, we, WILLIAM
PROSSER, Junior, of Pimlico, Esquire, and JEAN BAPTISTE CARCANO, of Milan,
Gentleman, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Eighteenth day of December, in the eighth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto us, the said
William Prosser and Jean Baptiste Carcano, Her especial licence, full power,
sole privilege and authority, that we, the said William Prosser and Jean
Baptiste Carcano, our exors, admors, and assigns, or such others as we, the said
William Prosser and Jean Baptiste Carcaño, our exors, admors, or assigns,
should at any time agree with, and no others, from time to time and at all
times during the term of years therein expressed, should and lawfully might
make, use, exercise, and vend, within England, Wales, and the Town of
Berwick-upon-Tweed, the Invention of "IMPROVEMENTS IN WORKING ATMO-
SPHERIC RAILWAYS," communicated to us by Monsieur Jean Baptiste Poiattie,
of Milan; in which said Letters Patent is contained a proviso that we, the
said William Prosser and Jean Baptiste Carcano, or one of us, shall cause a
particular description of the nature of the said Invention, and in what
manner the same is to be performed, to be inrolled in Her said Majesty's
High Court of Chancery within six calendar months next and immediately
after the date of the said in part recited Letters Patent, as in and by the
same, reference being thereunto had, will more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, we, the said
William Prosser and Jean Baptiste Carcano, do hereby declare that the
nature of the said Invention, and the manner in which the same is to be per-
formed, are fully described and ascertained in and by the following statement
thereof, reference being had to the Drawing hereunto annexed, and to
the figures and letters marked thereon (that is to say):
The Invention has for its object improvements in arranging apparatus used
for working railways by the pressure of atmospheric air acting on pistons
moving in traction pipes with longitudinal slits or openings. And the Iuven-
tion consists,
First, of so arranging the valves used for closing the longitudinal openings
or slits in the traction pipes that they shall open inwards, combined with the
use of suitable transverse valves or slides at proper interval in the traction
pipes for the air to press against when moving the pistons.
Secondly, the Invention consists of the application of reservoirs for receiving
air in a compressed state to such traction pipes of atmospheric railways as have
valves opening inwards to cover the longitudinal slits or openings, together
with transverse valves or slides for air under compression to act against when
propelling pistons in such traction pipes. And,
Thirdly, the Invention consists of causing the air which has been used in
a traction pipe of atmospheric railways, to be returned back into reservoirs
to be again used.
And in order that the Invention may be most fully understood and readily
carried into effect, we will proceed to describe more in detail the construction
and mode of working of the apparatus for moving carriages on railways; but
we would first remark, that at present the only railway worked by the pressure
of atmospheric air operates by means of a vacuum or partial vacuum, obtained
in front of the piston in the traction pipe or tube, the atmospher pressing
behind the piston; and it will be well also to remark, in order that the extent
of claim made by us to invention may be fully understood, that we are aware
that it has before been proposed to propel carriages on railways by means of
compressed air, but in such cases the pipe containing the air had not a longi-
tudinal valve opening inwards, combined with suitable transverse valves for
the air to press against.
inwards; this traction pipe is fixed between two rails in like manner to the
traction pipes in use for other atmospheric railways. The longitudinal valve a

page_text: is hinged at b, and the valve consists of a long fillet of strong leather, or of
other strong flexible substance suitable for such purposes, and the same is
strengthened by means of narrow metal plates fixed on the upper side in a
similar manner to what has been heretofore resorted to for strengthening the
longitudinal valve of the atmospheric railway now at work, and those which
are now being constructed. The upper surface of the valve is to be coated
with hard grease, particularly at the bearing edges, so that when the valve is
pressed outwards by the compressed air within the traction pipe the joint will
be rendered air-tight. The air may, if desired, be at once forced from the
pumps used into the traction pipe, by having suitable connection pipes between
the pumps and the traction pipe of a railway, in a similar manner (but_revers-
ing the action) to that now arranged for railways where vacuum or partial
vacuum is resorted to for obtaining the pressure of the air. But we prefer
that there should at intervals (in a line of railway which is to be worked
according to our Invention) be large reservoirs to receive air from the pumps
worked by steam or other power, and that the reservoirs should be connected
by pipes with the traction pipe, and we prefer that there should be three
reservoirs at each station in order that the power employed may be as small
as possible, so as by working continuously both when the trains are moving
as well as when they are not moving, the power employed may be as economical
as possible, as this arrangement, we believe, will be found generally more
advantageous than having large power simply in action when the trains are
moving and standing motionless, yet consuming fuel when the trains are not
running. The reservoirs will be strong vessels, similar to large boilers, and.
of a strength in proportion to the degree of compression to which the air is
subjected therein, which will be varied according to the peculiar circumstances of
the traffic and the gradients, but we do not consider it desirable to have the air
used in a high degree of compression, though the same allows of traction pipes
of less diameter, as will readily be understood by the engineer. We construct
the reservoirs for condensed air, each of a capacity equal to the contents of the
length of traction pipe it is to work with, the valves or slides used between the
reservoirs and the traction pipes being progressively opened, so that the air may
be maintained as near as may be at the same density in the traction pipe at start-
ng as at the end of a section of traction pipe; for it will be understood that as the
air in the reservoir is more dense at starting than at the end, the admission of
he air to the traction pipe should at starting be what is technically called "wire.
rawn," gradually opening the valve as the air becomes less and less in its
pressure in the reservoir. The traction pipe is divided into sections by valves
r slides.
We prefer to use flap valves for closing the traction pipe trans-.

page_text: versely, and we enlarge the traction pipes at those places where such flap valves
are to be used, so that they, when open, may be down out of the way of a
passing piston, and when up that they may have proper. seats to press against;
and as it is desirable to have the means of travelling in either direction by the
aid of the same traction pipe, we form two inlet valves near together at:
each place where air is admitted, having the inlet pipe conveying the air from
a reservoir or pump branched, so as to enter under these two valves, there
being suitable throttle or other valves in the branches of the pipe to determine
by which way or branch the air shall enter into the traction pipe, and according
as one or other is open so will the flap valve above be closed and the piston
will be propelled away from that valve, the valve for the time being across the
traction pipe resisting. the air passing in the opposite direction, whilst the
other transverse valve will be open and over the opening where the other
branch enters the traction pipe, by which the piston will be free to pass over
that other transverse valve. By thus using flap- valves these transverse valves
will close by the pressure of the air or remain open according as the air.
comes in at one or other of the branch pipes, and such flap valves will not
interfere with the passage of the piston in the way it is travelling, as the next
valve will not close till after the piston has passed it, for until that has taken
place the air would not be turned on to close that valve and press forward the
piston. The piston used is similar to that now. employed in Ireland, on the
atmospheric railway, and which is well understood, but there is no apparatus.
necessary to open or close the longitudinal valve, which we prefer to have so
arranged that it will have a slight tendency to fall open to allow of the passage
of the instrument which connects the piston rod with the carriage, as is well
understood; but in this case. this instrument will precede the piston, the piston
and the pressure of air in the traction pipe closing. the valve, as it comes up to
it, and the air in the traction pipe before the valve will pass or flow freely out
of the traction pipe through the longitudinal slit or opening. It will, however,
be understood, that if the tendency of the longitudinal valve to remain open
is not sufficient, the flow of air out at the slit or. longitudinal opening. would
tend to close it; if; therefore, it is preferred to have the valve so, stiff as to
tend to close, then the instrument connecting the piston rod to the carriage
should have a projection sufficiently, long to press open the longitudinal valve
some distance before the piston, to allow. of space for the passage of air from
the traction pipe. It will be evident that as the section of traction pipe along
which a train of carriages has just been. moved will be full of compressed air
and that such compressed air may be more economically returned back into a
reservoir than by pumping from the atmosphere, for it will be. understood, tha

page_text: in again filling a reservoir from the atmosphere the pressure on one side of the
pump piston would be the atmosphere, and on the other side the pressure due
to the compressed state of the air remaining in the reservoir, and that
pressure would be continually encreasing, the pressure of the atmosphere
remaining constant, whereas, if the air be returned from the traction pipe
into a reservoir the pump piston will commence from a state of equilibrium,
consequently requiring comparatively little, power, such power increasing as
the density of the air remaining in the traction pipe decreases down to the
atmospheric pressure; hence an engineer will readily perceive that by a
suitable arrangement of valves and pipes he may beneficially employ part of
the power of the engine for transferring the air from the traction pipe back
into the reservoir. In using this part of our Invention a suitable slide or
other valve must be caused to close the end of the section of the traction
pipe as the piston leaves it, so that the air may be closed from passing beyond
the section if the traction pipe, end there, but where the one section of the
traction pipe is continued by another section, only having a slide or flap valve
between them, then the closing of the next of the transverse valves will be
sufficient. This means of working atmospheric railways, like those heretofore
proposed, may be used on double or single lines,, but we believe that. single.
lines, will be generally found sufficient; in which case the working of the
valves and the engines, and the general working of the railway, will be greatly
facilitated by the use of the electric telegraph; and where single lines of
railway are preferred, then at stations where trains are to pass each other the
lines will require to be double, in which cases very little delay will will take
place between the passing of trains from and to a section of the traction
pipe in opposite ways; for no sooner is one train gone than at that instant the
piston of the other train may enter the same section of traction pipe, it being
understood that when this instantaneous passing in opposite ways of two.
trains be desired then the benefit of using the third part of our Invention in
those sections of the pipe will, for the time being, be dispensed with.
Having thus described the nature of our Invention, and the best means we
are acquainted with for performing the same, we would have it understood
that we do not confine ourselves to the details herein described, so long as the
But what we
peculiar character of either part of our Invention be retained.
claim is,―
First, the mode of working atmospheric railways herein described, whereby
the longitudinal slits or openings in traction pipes of such railways have lon-
gitudinal valves which open inwards, combined with the use of suitable

page_text: transverse valves or slides at proper intervals for compressed air to press
against.
Secondly, we claim the mode of working atmospheric railways herein
described, whereby the use of reservoirs of compressed air is combined with
traction pipes with longitudinal valves opening inwards, and with transverse
slides or valves for the compressed air to press against. And,
Thirdly, we claim the mode of working atmospheric railways herein
described, whereby compressed air is returned back from the traction pipes
into reservoirs.
In witness whereof, I, the said Jean Baptiste Carcano, have hereunto 1
set my hand and seal, this Eighteenth day of June, in the year of our
Lord One thousand eight hundred and forty-five.
JEAN BAPTISTE DE (L.s.) CARCANO.
AND BE IT REMEMBERED, that on the Eighteenth day of June, in
the year of our Lord 1845, the aforesaid Jean Baptiste Carcano (through the
interpretation of William Henry Ritchie, of Lincoln's Inn, Gentleman, the
said William Henry Ritchie having been first sworn that he had truly and
faithfully interpreted the contents of this Specification and also the nature
and purport of this acknowledgment to him the said Jean Baptiste Carcano)
came before our said Lady the Queen in Her Chancery and acknowledged the
Specification aforesaid, and all and every thing therein contained and specified,
in form above written. And also the Specification aforesaid was stamped
according to the tenor of the Statute made for that purpose.
Enrolled the Eighteenth day of June, in the year of our Lord One thou-
sand eight hundred and forty-five.