IMPROVEMENTS IN ATMOSPHERIC RAIL- WAYS
Year: 1844

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
AITKEN, of Surrey Square, in the County of Surrey, 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 Twenty-fourth day of February, in the seventh year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said John Aitken, Her especial licence, full power, sole privilege and
authority, that I, the said John Aitken, my exors, adiñors, and assigns,
or such others as I, the said John Aitken, my 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, my Invention of "IMPROVEMENTS IN ATMOSPHERIC RAIL-
WAYS;" in which said Letters Patent is contained a proviso, that I, the said
John Aitken, shall cause a particular description of the nature of my 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, I, the said
John Aitken, do hereby declare that the nature of my said Invention, and
the manner in which the same is to be performed, 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):-
In the various constructions of atmospheric railways which have heretofore
been proposed, and in those which have been constructed, the air from what
may be called the traction pipe has been removed by means of air pumps in
order to obtain the desired vacuity; and it is well known that in working air
pumps to obtain a vacuum in such traction pipe there is considerable difficulty
in getting out the air so as to obtain a good vacuum, owing to the pumps
removing more and more rarified air at each succeeding stroke, so that the
weight of air removed at each succeeding stroke is less than the previous
one, and it has been found in practice better to use a moderate vacuum than to
attempt to obtain a perfection of vacuum.
Now the object of my Invention is, first, to obtain the requisite vacuum in
the traction pipes of atmospheric railways by causing them to be filled with
water, and then by means of eduction pipes (thirty-two to thirty-three feet
long) descending from the traction pipes to carry off such water, leaving a
better vacuum in the traction pipes than can with convenience be obtained
by air pumps; or in place of such length of eduction pipes I can use pumps
with shorter eduction pipes, so that at each stroke of a pump so used to with-
draw a quantity of water equal to the cubic contents of the cylinder of the
pump, which will leave a like cubic contents of the traction pipe vacuous.
By either of these means I can more effectually and advantageously obtain
the requisite vacuum for working atmospheric railways. And, secondly, my
Invention has for its object the use of water for covering the longitudinal valve
of the traction pipe so as to retain the vacuum obtained therein.
And in order that my Invention may be most fully understood, I will proceed
to explain the best means I am acquainted with for carrying the same into
effect.
The traction pipe is, as heretofore, to be constructed with a longitudinal
opening or slit, covered by a valve made of leather or other suitable mate-
rial, suitably prepared for resisting the action of water, as is practised in
preparing such materials for the buckets of pumps and other purposes, as is well
understood. This valve should be strengthened by numerous parallel narrow
plates of metal fixed side by side across the valve, as has before been practised,

page_text: and such valve may be attached at one of its edges to the side of the slit or
opening in the traction pipe, as is now practised in the atmospheric railway in
Ireland; or the valve may be wholly separated from the traction pipe and
simply cover the slit or opening, as has before been suggested by others. And I
would here mention that I make no claim to any peculiar construction of
traction pipe nor longitudinal valve for the same, nor do I claim any novelty in
the construction of other valves to be used in working atmospheric railways,
my Invention being confined to the use of water as herein described for
obtaining and mainting a vacuum in the traction pipes employed for working
atmosperic railways; and as the various details of apparatus of atmospheric
railways form no part of my Invention, it will not be necessary for me to
describe the same further than is required for explaining how water is to be
used in obtaining and mantaining the requisite vacuum in the traction pipes
of atmospheric railways. The carriages will be connected with a piston as
heretofore, and the requisite means of opening and again closing the longi-
tudinal valve employed will be applied when using water, as when using
air pumps for obtaining the vacuum have been resorted to. The traction
pipe for a railway I place between the two rails, but in place of affixing
the traction pipe on the earth, I cause a trough to be formed of such size and
depth as that the water contained therein may cover the traction pipe some
inches, as will be better understood on examining the Drawing, where
Figure 1 is a tranverse section of a traction pipe in a trough. Figure 2 is a
longitudinal section, and Figure 3, a plan of part of a traction pipe; a, being a
transverse slide; b, the slide box; c, c, the longitudinal opening in the traction
pipe and d the longitudinal valve, the nature of which has before been
explained. When constructing a railway on a horizontal plane, then it will be
evident that there will be no difficulty in maintaining the trough full of water
from a stream, or by means of pumps from wells, according to the advantages
offered in the particular locality; and in such cases it will only be necessary
to employ valves in such lengths of the traction pipe as will be required to be
rendered vacuous at one time, and where the vacuum is not required to be
repeated at quick intervals of time only one eduction pipe would be required in
a mile, or other greater length, as time may be allowed for running off the
water and obtaining the vacuum in the traction pipe before the carriage or
train of carriages start, and the speed of removing the water may be hastened
by having more eduction ways; and it will be evident that as the longitudinal
valve is lifted the pressure of the atmosphere will force the water into the
traction pipe, and the air and water will press forward the piston into the.
;

page_text: acuous traction pipe, the water filling up the traction pipe behind the
piston, the valves on the water eduction ways being closed as soon as the
vacuum has been obtained, and thus the traction pipe will be again in a con-
dition to be rendered vacuous, and when desired the transverse valves in the
traction pipe may be immediately closed after the passage of a carriage,
and thus the previous part of the traction pipe may be again rendered
vacuous for a succeeding carriage or train of carriages, and such transverse
valves should in all cases be used at water eduction ways, so that the same
person who attends to one valve may attend to the other, and the correct
working of the valves will be greatly facilitated by having electric telegraphs
along the lines of railway to intimate to the men on the line what is required
to be done with the valves from time to time. In constructing railways up
ascending planes, and applying my Invention thereto, it will be evident that
provision must be made for preventing the water on the interior of the traction
pipe opening the longitudinal valve, and I prefer that there should in such
cases be no greater length between two transverse valves a than will give a
pressure of more than one foot of water between the highest and the lowest
point of the traction pipe between two such valves, and then that the weight of
the longitudinal valve should be greater than the pressure caused by such
internal pressure of a foot column of water; and in order to keep the upper
surface of the longitudinal valve covered with water, I supply the water to the
highest point or at several points constantly, and allow it to flow downwards;
and where I cannot get a sufficient supply of water at the highest point, then I
pump the water from the lowest point again back to the upper point, keeping
the longitudinal valve at all times well covered with water. It will be evident,
where the requisite vertical length for the eduction water pipes can be con-
veniently obtained with a sufficient supply of water, that will be the better way
of applying my Invention, and the eduction pipes are to descend into water
below, or have their lower ends bent up; but where the requisite vertical
column cannot be obtained with convenience, then I use short water eduction
ways with pumps in such manner, that the pumps working in the water will
remove the cubic contents of the spaces moved through by their pistons at each
stroke, and where necessary (owing to the supply of water from other sources
being short or otherwise not to be obtained) I return such water into the
trough containing the traction pipe, so that the water may be used over and
over again.
Having thus described the nature of my Invention, and the best means I am
acquainted with for performing the same, I would have it understood that

page_text: what I claim is, the mode of constructing and working atmospheric railways
whereby water is used as a means of obtaining the necessary vacuum in the
traction pipes, and also for retaining the longitudinal valve air-tight, as herein
described.
In witness whereof, I, the said John Aitken, have hereunto set my
hand and seal, this Twenty-second day of August, in the year of our
Lord One thousand eight hundred and forty-four.