IMPROVEMENTS IN RAILWAYS, AND IN PROPELLING RAILWAY CARRIAGES
Year: 1845

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, we, WILLIAM
PROSSER, junior, of Pimlico, Esquire, and JACOB BRETT, of Hanover Square,..
both in the County of Middlesex, Gentleman, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Tenth day of May, in the eighth year of Her reign, did,.
for Herself, Her heirs and successors, give and grant unto us, the said William.
Prosser, junior, and Jacob Brett, our exors, adññors, and assigns, Her especial
licence, full power, sole privilege and authority, that we, the said William
Prosser, junior, and Jacob Brett, our exors, admors, and assigns, or such others
as we, the said William Prosser, junior, and Jacob Brett, 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, and in the Islands of Guernsey, Jersey, Alderney, Sark,
and Man, and also in all Her said Majesty's Colonies and Plantations abroad,
our Invention of "IMPROVEMENTS IN RAILWAYS, AND IN PROPELLING RAILWAY
CARRIAGES;" in which said Letters Patent is contained a proviso, that we,
the said William Prosser, junior, and Jacob Brett, shall cause a particular
description of the nature of our 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 or
the said in part recited Letters Patent.

page_text: NOW KNOW YE, that in compliance with the said proviso, we, the sam
William Prosser, junior, and Jacob Brett, do hereby declare that the nature
of our 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 Drawings hereunto annexed, and to the figures and
letters marked thereon, that is to say:-
Our improvements in the mode of applying the pressure of the atmosphere
to produce propulsion on railways, peculiar formation of the valve commonly
known as the long valve of the atmospheric pipe or main, to prevent the
leakage of air into the pipe from this source, and also to allow of two valves on
one pipe, by which means a double line of railway may be economically and
advantageously used with a single atmospheric pipe or tube, which may also be
of smaller diameter and much thinner metal than the common atmospheric
tube. This we effect by forming our-pipe or main a, a, Drawing A, Figures
1, 2, and 3, with a continuous series of longitudinal or circular apertures b, b,
instead of an uninterrupted groove or slit, for obtaining a, communication
between the interior and exterior of the pipe, with solid parts or narrow trans-
verse bars c, c, at short distances, which at these parts render the circle of the
pipe complete, and thus prevent any tendency to collapsion from external
pressure on the pipe. One form of our valve consists of two semi-cylindrical
surfaces of flexible leather, or similar substance, d,.d, Figures 1, 2, and 3, the
lower edges of which are fastened down on each side of the groove..or
longitudinal series of apertures, and their upper edges attached to longitudinal
bars e, e, supported above the groove by brackets n, n, attached to the main;
while the convex cylindrical surfaces abut against each other by the action of
the metallic springs f, f, and the elastric strips of wood m, m, and the atmo-
spheric pressure. When a partial vacuum is formed in the pipe, a metal plate
or bridge g, g, perforated like a honeycombe, is placed over the groove or
series of apertures, and extending the entire length of the pipe or main,
supports the strips of leather d, d, and prevents their being pressed downwards
by the superincumbent weight of the atmosphere. For a double line of rails
the pipe or main is. furnished with two such valves, running parallel to each
other, and extended the entire length of the pipe, as, shewn in Figure 2.
Another form of the valve is shewn in Drawing B, Figure 1. The letters of
reference correspond to those of the preceding Figures. h, h, are longitudinal
bars of iron, which fasten down the leather flaps d, d, to the pipes by means
of the bolts and screws i, i, in Figure 2, B; j,j, are two plates of thin sheet
iron or other metal, which we sometimes use to protect the leathers d, d, from

page_text: the action of the weather, and to retain a fibrous packing k, k, saturated with
an unctuous substance, to maintain the flexibility of the valve and render it
impermeable to air. The joinings of the lower edges of the valve leathers with
the pipe or main are rendered air-tight by an unctuous .cement. We also
propose to form a channel over our valve formed of thin metal plates, furnished
with a flap or cover, which rises to allow the passage of a sliding pipe or bar,
and closes again to protect the valve from the weather. Our pipe or main is
continuous throughout the entire length of the line, and at stated distances
communicates by means of lateral pipes with air pumps or pneumatic ex-
hausting machinery, moved by steam or other power, such air pumps or
exhausting machinery to be placed at intervals of six milés or upwards along
the line. For propelling our carriages or trains we use small locomotive
engines with reciprocating or rotary pistons, acting by the pressure of the
atmosphere against a partial vacuum; a flexible tube, constructed so as to bear
external pressure without collapsing, communicates between the eduction
passages of the locomotives and the interior of the pipe or main through a tube
of thin steel, shewn in plan at 1, 1, Figure 3, A, which is inserted between the
leathers of the valve, and when drawn forward slips along between the valve
leathers, which it forces open to admit its passage, and which immediately close
again by the external pressure. This sliding tube has a guide wheel P, which
runs on the ridge of the bridge g, g, and it is connected with the locomotive by
the aforesaid flexible pipe and by projecting arms or guide rods, possessing
sufficient elasticity to allow for vibration or slight déflection without disturbing
the fitting of the slide pipe in the valve. A partial vacuum being formed in
the atmospheric pipe or main by the action of the stationary air pumps, and the
communication being opened between the eduction passages of the air loco-
motive engine and the interior of the main, the entire atmospheric pressure is
exerted on one side of the locomotive pistons, while a partial vacuum exists on
the other side of the pistons, which will be moved with a force corresponding
to the difference of the pressures' on their opposité surfaces.. This' motion
of the pistons being communicated to the driving wlieels by means of
any suitable mechanical arrangement, will propel forward the air loco-
motive, which will draw after it a train of carriages, as in the case of steam
locomotives. The eduction pipe 1, Figure 3, A, moving along with. the
locomotive to which it is attached, and sliding air-tight between the longi-
tulinal valve leathers, maintains a constant communication between the interior
of the exhausted main and the locomotive cylinders at whatever velocity they
may be moving along the line. By means of the double valve on one pipe

page_text: laid between a double line of rails, as already described, it is evident that two
trains can pass each other without causing the slightest disturbance or derange
ment to the apparatus. By increasing or diminishing the admission of air to
the working cylinders the motion may be regulated at pleasure; and by shutting
off the air and reversing the valve motion the train is stopped, and if requisite
moved in the opposite direction. To obtain greater economy in working, the
+locomotive engines are arranged to work by the expansive action of air, either
in single. .or double expansion cylinders. When greater power is required, as
in ascending inclines, the engines are worked at full pressure. In descending
with considerable gradients, the valve action is so modified that the locomotive
cylinders exhaust air out of the main, and the motion of the train descending
by gravity is thus not only checked and modified, but a corresponding amount
of power is generated in the main, to be again given out to the locomotives,
when required. To modify the speed on very steep descents, or to stop the
train on any part of the road, the valve motion and the air passages are so
arranged that after the eduction passages are closed, the pistons of the loco-
motives worked by the momentum of the train force air into a reservoir fixed
on the locomotive, which thus acts most effectually as an air break, and since
the air locomotive cylinders being worked by a slight pressure compared to
steam are of large area in proportion to the weight they carry, the train is
brought to a state of rest in the shortest time, and without less of power, and
the wear and tear of the wheels and rails caused by the action of common
breaks. The power lost by the friction of common breaks is here stored up
in the compressed air, which is allowed to expand again when the train has to
be started, and thus, serves moreover as a reservoir of power sufficient to move
on the train from the siding, where the valve connection with the main
may be interrupted, until the slide pipe is again inserted between the valve
leathers, and the communication between the air locomotive and the exhausted
main is again established; a hand pump is sometimes used for this purpose;
at crossings, or slidings the main or pipe is depressed below the level of the
road, as shewn in Drawing B, Figures 3, 4, 5, 6, and the long valve is discon-
tinued on such depressed parts of the pipe. Figures 5, 6, B, show the mode
of closing the extremities of the long valve. The strips of leather d, d, extend
downwards to the depressed pipe, where they are fastened, and the springs o, o,
press them into close contact. Towards their extremities q, q, the valve
leathers diverge, as shewn in plan, Figure 6; and at the diverging parts their
inner surfaces are lined with thin plates of smooth metal. The exit of the
slide tube from one section of valve and its. entrance into the next are thus

page_text: efficiently provided for. Our atmospheric pipe or main is, as already stated,
continuous throughout its entire length, and under ordinary circumstances does
not require any section valves, or entrance or exit valves, as there is no piston
in the main, which is in effect only a connecting pipe between the exhausting
machinery and the locomotive cylinders; but under peculiar circumstances
it may be advantageous to have the main divided into sections, and it is there-
fore furnished with separating valves at the stations, which valves may be
closed by hand, when required. Should any arrangement of the main or valve
take place at any part of the line, so as to cause excessive leakage of air,
the station valve on each side of the defective main should be closed, either by
hand whenever the barometer gauge at the station indicated an excessive
admittance of air, or by an arrangement which would close the valve automa-
tically from the same cause, and thus the effect of the derangement of the
main would not extend beyond the section where it occured. As under
ordinary circumstances our main is continuous throughout its entire length, it
is obvious that each lateral exhausting pipe, connecting the main with the air
pumps, will draw out the air from the main equally on either side of it, and if
the stationary air pumps are six miles apart, an air locomotive on the line can
never be more than half this space or three miles distant from an air pump;
thus our air pumps may be set at a considerable distance apart, and yet exert
a comparatively immediate effect on the locomotive pistons, as the main is of
small diameter, having merely to perform the office of a connecting pipe, and
not being subject to collapsion in the absence of the continuous chase or
longitudinal aperture, as already described. We propose to construct it in some
cases of sheet iron, protected from oxidation and the effects of the weather by
being galvanized or coated with bituminous or other waterproof cement, or by
both these means, either with cast or sheet iron pipes; the perforated valve
bridge may be formed in one piece with the pipe. To allow the air which
enters the main from the vacuum locomotives greater space for expansion,
air-tight reservoirs of masonry or other suitable material are constructed at
ntervals along the line, and communicate by lateral connecting pipes with the
nterior of the main, so as to be equally exhausted. Under ordinary circum-
tances the main will be kept in a constantly exhausted state by the continuous
ction of the stationary engines, which may consequently be of comparatively
mall power, and light trains may be dispatched at very frequent intervals with
reat convenience and economy, therefore under ordinary circumstances the
ommunication between the main and the vacuum reservoirs should be free
nd uninterrupted; but valves or stop-cocks are provided, so as to be used

page_text: under peculiar circumstances, if required. As the air locomotives would be
extremely light compared with steam locomotives, luggage or passengers may
be carried on the locomotive carriage, which, unlike the common locomotive, is
entirely free from danger and inconvenience, and the system is peculiarly
suitable to the employment of wooden rails, which would give sufficient
adhesion for any required amount of traction. It is well known that the
specific heat of rarified air diminishes more rapidly than the diminution of its
volume and its capacity, for heat becomes greater as the exhaustion proceeds,
and it accordingly absorbs heat from the metal of the pipe which encloses it,
until its increased capacity for caloric is satisfied. In its rarified and expanded
state it will now be of the temperature of the surrounding atmosphere; but
if its volume is again compressed until it becomes of common atmospheric
pressure, the excess of caloric which remained latent in its rarified state
will now become sensible, and will raise the temperature of the whole very
considerably. It has been stated from observation that the air issues from the
air
pump at a temperature considerably above the boiling point; (it has been
stated by Brunel at about 250°). It is well known that air expands one four-
hundred-and-eightieth of its volume with an increase of each degree of tem-
perature of Fahrenheit's scale, consequently one volume of air at sixty degrees
would become 13 volume at two hundred and twenty degrees, and under these
circumstances the pump having to discharge into the atmosphere 13 volume of
air, while the resulting effect in the main is only equal to the exhaustion of one
volume, it is evident that one-third of the whole power employed is lost or
exerted without producing any equivalent tractive effect in the main; covering
the tube externally with a bad conductor of heat would not effectually remedy
this evil, as the great specific heat of the metal (which weighs about one
hundredweight to each lineal foot of main) would still be communicated to
the rarified air. An internal coating of some non-conducting substance would
prove an effectual remedy; and besides an externel coating, we propose to coat
or line our main internally with some bad conductor of heat, as felt saturated
with bituminous cement, thin wood, or other suitable substance; such coating or
lining will be permanent, as no piston passes through this pipe. (We also
propose to coat or cloathe the exterior of railway atmospheric pipes in general
with non-conducting substances, to prevent the transmission of heat.) In
atmospheric pipes which are traversed by a propelling piston, we also form the
long valve as shewn in section by Figure 7, B. The valve r, formed of strips
of well-seasoned wood, connected so as to form one continuous length, and
coated with leather or similar elastic material'on its under surface; closes the

page_text: chase or longitudinal aperture t, and is moyed laterally by the passage of the
plate. which connects the piston rod with the leading carriage, thus forcing a
communication between the interior and exterior of the pipe. After the
passage of the piston the valve is returned to its original position. by, the elastic
action of the springs s, so as to reclose the longitudinal aperture,. while, the
weight of the external atmosphere presses down the valve into close contact
with its seat, and thus prevents leakage.
two
The
We claim the peculiar formation of the valves as applied to air locomotives.)
videlicet, two strips of soft elastic leather abutting against each other, cither by
the combined action of longitudinal springs and the atmospheric pressure, or
simply by the external pressure of the air, and supported on a perforated bridge.
The substitution of a series of apertures for a continuous slit or chase, by which
means collapsion is prevented, even with very thin metal. Two valves on one
pipe, resulting from or depending on the preceding peculiarity of construction,
thus making one pipe answer for a double line of rails; the main continues
throughout without section valves or internal interruption of any kind in the
ordinary course of working, so that a locomotive on the line can never be more
distant from an air pump than half the distance between any pumps.
expansive action of air in the locomotive cylinders, which is requisite to insure
economy in working, making the locomotive cylinders to exhaust on a descent,
when requisite to checking the effect of gravity, and at the same time
generating an equivalent amount of power, causing the locomotive cylinders to
force air into a reservoir on the carriage or locomotive, thus making the
compressed air act as a most effective break, and subsequently to act by its
elasticity or expansive force as an independent source of power to start the
train by working the locomotive cylinders. Attaching the slide pipe to the
locomotive by means of flexible tubes prepared so as to prevent collapsion, and
by connecting rods, &c., having a certain degree of elasticity. The manner of
discontinuing and closing the long valve at those parts where the main is
depressed below the level of the road (see Figs. 3, 4, 5, 6, B), vacuum reservoirs
at intervals along the line in free communication with the main in the ordinary
course of working. Using sheet iron for the pipe or main. Coating the main
inside or inside or outside of cast-iron tubes with non-conducting substances.to
prevent the absorption of heat by the rarified air.
In witness whereof, I, the said Jacob Brett, have hereunto set my hand
and seal, this Tenth day of November, in the year of our Lord One
thousand eight hundred and forty-five.
JACOB BRETT.
(L.S.)

page_text: AND BE IT REMEMBERED, that on the Tenth day of November, in the
year of our Lord 1845, the aforesaid Jacob Brett 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 Tenth day of November, in the year of our Lord One thou-
sand eight hundred and forty-five.