A CERTAIN IMPROVE- MENT IN THE LOCOMOTIVE STEAM ENGINES NOW IN USE FOR THE QUICK CONVEYANCE OF PASSENGERS AND GOODS UPON EDGE RAILWAYS
Year: 1833

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
STEPHENSON, of Newcastle-upon-Tyne, in the County of Northumberland,
Engineer, send greeting.
WHEREAS I did by petition humbly represent to His present most Excel-
lent Majesty King William the Fourth that I had invented "A CERTAIN IMPROVE-
MENT IN THE LOCOMOTIVE STEAM ENGINES NOW IN USE FOR THE QUICK CONVEYANCE
OF PASSENGERS AND GOODS UPON EDGE RAILWAYS;" and His said Majesty being
willing to give encouragement to all arts and Inventions which may be for the
public good, was graciously pleased to issue His Royal Letters Patent, bearing
date at Westminster, the Seventh day of October, in the fourth year of His
reign, by which said Letters Patent His said Majesty, for Himself and His
successors, doth give and grant unto me, the said Robert Stephenson, my execu-
tors, administrators, and assigns, His sole privilege that I, or they, and such
others as I, or they, should from time to time agree with (and no others), at
all times during the term of fourteen years from the date of the said Letters
Patent, might lawfully make, use, exercise, and vend, my said Invention
within England, Wales, and the Town of Berwick-upon-Tweed; in which
said Letters Patent there is contained a proviso, obliging me, the said Robert
Stephenson, to particularly describe the nature of my said Invention, and in
what manner the same is to be performed, by an instrument in writing under
my hand and seal, and to cause the same to be enrolled in His Majesty's High

page_text: 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, (refer-
ence being thereunto had,) will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Robert Stephenson, do hereby declare that my said Invention is described in
manner following, that is to say :-
My improvement in the locomotive steam engines now in use, for the quick
conveyance of passengers and goods upon edge railways, is applicable to that
kind of locomotive engines which are used on the Liverpool and Manchester
Railway (the first of which engines was called by the name of the Planet),
having the two main wheels, which are impelled by the engine, fixed on a double
cranked axis, and turned round by the force of the pistons of the steam
cylinders, in order to advance the locomotive engine along the edge rails
whereon the said main wheels bear. And my said improvement consists in
making the said main wheels of the locomotive engine (which are fixed as
aforesaid) on the ends of the cranked axis, and impelled by the force of the
pistons, with plain tires, to run upon the edge rails without any projecting
flanges on those tires, and applying two additional small wheels with flanges
on their tires, beneath the hinder end or part of the engine, in order to cause
that end of the engine, by means of these flanges, to keep straight upon the
rails as it runs along thereon, and also to bear up part of the weight of the
furnace end of the boiler, in the same manner as the present two small wheels
(by means of their flanges) keep that end of the engine straight on the rails
and bear part of the weight at the chimney end of the the boiler where the
steam cylinders are situated; and also consists in applying the force of small
extra steam pistons, or plungers, fitted into suitable cylinders, which, by
turning a cock, can be supplied, when required, with steam from the boiler, in
order to act upon a double brake, or pair of clogs, which are applied to the
circumferences of the tires of the said main wheels without flanges, and of the
two said additional small wheels with flanges, so as to press the said brakes or
clogs in contact with the said circumferences, and thereby cause friction and
resistance, which will tend to retard the motion of the wheels, and consequently
the advance of the engine along the rails, in order to stop the same when
required.
The object of my said improvement is to obviate or diminish some incon-
veniences which have been experienced in the use of such locomotive
engines for the quick conveyance of passengers and goods on the said Liver-
pool and Manchester Railway, viz, that the cranked axles of the great wheels
have been found liable to break, and then the engines run off the rails, and

page_text: sometimes overturn or are otherwise injured. They have also in some cases
run off the rails when the cranked axle has been only strained, without being
actually broken. Also it is found difficult to hold on with the clogs or brakes
to the wheels of such locomotive engines, according to the manner whereby
the brakes are usually applied by hand, with sufficient force and steadiness to-
retard the engines from advancing along the rails, as much as is desirable,
in order to arrest their motion as suddenly as possible, when they have been.
travelling rapidly, and particularly in the event of arriving at a broken or
deranged part of the railroad, or on any other occurrence which may occasion
danger of collision with obstacles or other carriages, if the motion were not-
stopped with promptitude; and also the boilers of those engines have burned"
out very rapidly in their internal tubes, so as to have occasioned great expence
and loss of work in repairing them. My said improvement in such kind of
Jocomotive engines will tend to obviate or diminish the said inconveniencies,
for by using plain tires without flanges for the main impelled wheels (and
which has never been done before in such engines on edge railways) the
cranked axle of those wheels will not be subjected to any strain endways, in
the direction of its length, when the engine enters into sidings, turnings, and
crossings of the rails, or passes along curvatures in the line, for that is pro-
bably the most severe strain to which the cranked axles have been hitherto
subjected, and is thought to be that whereby they have been commonly
strained and broken, for at every siding, turn off, or curvature in the road the
locomotive engine will have a tendency to run off the rails sideways, and
which tendency can only be resisted or counteracted by the flanges on
the wheels bearing laterally against the inside edges of the rails, on the
concave side of their curvature; and in entering turns off the lateral bearing
of the flanges is very forcible, but it is evident that, to afford such a
resistance or counteraction to running off the rails, the axles on which
the wheels are fixed must be severely tried. The axles of the small wheels
in such engines being straight, and consequently shorter than the cranked
axles, and having only to bear a weight acting downwards, without any
twisting, and from the small size of those wheels, such straight axles
being strained laterally with a shorter leverage, have been found sufficiently
strong, and have been rarely broken, but the cranked axles being in con-
sequence of their cranked form) of much greater length, and being very
powerfully urged by the force of the pistons with a bending and twisting
action combined, have frequently failed, most probably from the additional
stress to which they have been subjected by the lateral action of the flanges of
the impelled wheels against the inside edges of the rails, whenever, from enter-

page_text: ing sideings, or turns off, or passing along curvatures of the railroad, the engine
has had a tendency to run off the rails, which lateral action of the flanges of
the impelled wheels against the edges of the rails, owing to the large size of
those wheels and the great length of the cranked axle, has operated with
powerful leverage to bend and break the cranked axle, and the instant that
from such cause the axle has been strained or bent, so as to put the main
wheels out of square with the axle, they would from that moment acquire an
increased tendency to lateral bending of the axle and running off with a side-
way lunging motion of the whole engine. It is evident that any lateral bend-
ing of the cranked axle, although far short of a fracture, will, by putting the
wheels out of square, produce a violent surging motion of the whole engine
sideways in its further progress along the rails, and such an extra action must
be very liable to break the cranked axle, or run the engine off the rails. The
said tendency to bend or break the cranked axle will be very greatly
diminished by divesting the tires of the main impelled wheels of their flanges
and trusting entirely to the flanges of the two additional small wheels which
must, according to my improvement, be applied beneath the fire-place end of
the boiler, for keeping the engine straight on the rails in its progress forwards;
and the axle of those wheels being straight may be expected to be sufficient
to be capable of enduring the stress to which it will be subjected in so keeping
the engine on the rails without breaking or bending, for the past experience
has proved the sufficiency of the present straight axles of the small wheels.
And by applying the pressure of steam from the boiler to act within hollow
cylinders upon pistons or plungers fitted into those cylinders, so as by the motion
given to those pistons by the steam when admitted into the said cylinders to
force the brakes or clogs against the edges of the wheels in order to retard the
same by causing friction, and thereby stopping the advance of the locomotive
engine on the rails, the stopping may thereby be effected with more promp
titude, and with less trouble, than by the ordinary mode hitherto practised of
applying the clogs or brakes by the strength of the man who attends the engine;
for according to my improvement, the man, when warned of any danger
requiring the locomotive engine to be stopped as suddenly as possible, after
having as usual stopped off the supply of steam to the engine cylinders,
will have nothing to do in order to apply the brakes or clogs but to turn
a cock in a small steam pipe which conducts the steam from the boiler into
the said hollow cylinders wherein the said piston or plungers are fitted,
and the steam, being (by opening the cock) admitted to act upon these
pistons or plungers, will bring the clogs or brakes into action with far more
effect than can be done by the common mode of pressing them against the

page_text: wheels by handle levers actuated by man's strength; and also, according
to my improvement, the man, after having opened the said cock, and so
brought the brakes or clogs into action by the force of steam, will have his
hands at liberty to do any other duty that may be required of him whilst the
engine is stopping. And note.-The same effect may be produced by admit-
ting water from the boiler by a pipe and cock, as aforesaid, into the said
hollow cylinders in lieu of steam, because the pressure of the water will
produce the same effect on the pistons or plungers and clogs or brakes as
that of the steam. And in order to release the said clogs or brakes, and take
them out of action, the aforesaid cock must be shut to cut off the communi-
cation from the boiler to the hollow cylinders wherein the pistons are to act,
and another cock being opened to permit the steam (or water) which has
operated in the hollow cylinders to escape therefrom into the open air, and
allow the pistons or plungers in those cylinders to return and release the brakes
or clogs, or the same cock which admits the steam or water from the boiler
into the said cylinders may be made with a double passage, so as to allow the
steam or water to escape into the open air when the cock is turned in an
opposite direction, or to shut both passages when turned into an intermediate
position. The inconveniency of wearing out the boilers may be diminished
when locomotive engines are constructed according to my said improvement;
for, by using six wheels to support the engine, larger boilers may be employed.
The additional small wheels which I apply beneath the hinder end of the boiler
will sustain the extra weight of a larger boiler than heretofore used without
distressing the rails, and bearing springs are to be used for the extra small
wheels, the same as is now done for other wheels in the ordinary engines, and
the said springs will cause all the six wheels to apply and bear fairly on the
rails, and case all jolts and concussions; the relative weights, or portions of
the whole weight of the engine which shall be borne by each of the six wheels
being regulated by the strength and setting of their respective bearing springs;
the main wheels which are to be impelled by the power of the engine, being
in all cases left loaded with as much of the weight of the engine as will cause
a sufficient adhesion of those wheels to the rails to avoid slipping thereon.
When, by virtue of my improvement, a larger boiler is used, containing more
heating surface than heretofore, a less intense excitement of the combustion
will be required in order to produce the necessary quantity of steam for the
supply of the engine, and that diminution of the intensity of the combustion
will be advantageous to the performance of the engine, for another reason as
well as by avoiding the heretofore rapid buring out of the metal of the boiler,
because the jet of waste steam (which is thrown into the chimney to produce

page_text: a rapid draft therein, and a consequently intense combustion of the fuel,) may
be greatly diminished in its velocity, and thereby the waste steam will be
allowed to escape more freely from the cylinders than heretofore, when a very
sharp and sudden jet of the waste- steam up the chimney is found absolutely
necessary to excite that intense violence of combustion which can alone enable
the present boilers to yield the requisite supply of steam; but that very sudden
jet can only be obtained by throttling the eduction passage, and thereby im-
peding the free discharge of the steam from the working cylinders, so as to
impair the force of the pistons, and at the same time the excessive combustion
which is excited (by so impairing the force of the pistons) also destroys the metal
of the boiler in a short time. Increasing the magnitude of the boiler, giving a
larger extent of heating surface thereto, and working the enlarged boiler with a
more moderate intensity of fire, is the true remedy and will save fuel, as well
as avoid the rapid destruction of the boiler, because the steam will be allowed
to escape more freely from the cylinders.
The adoption of larger boilers in the said locomotive engines, with all the
advantages to be derived therefrom as aforesaid, depends upon the applica-
tion of the two additional small wheels beneath the furnace end of the boiler
because the present engines are already too heavy on the rails, and require a
diminution of weight instead of an augmentation.
But I wish to be understood that I do not claim the use of six wheels
instead of four, as an improvement merely for better supporting the weight,
distinct from other circumstances herein-before set forth, but I claim the
use of large wheels without flanges in their tires, which wheels are to be
fixed on the cranked axle, to serve for the impelled wheels of locomotive
engines, which are to travel on edge railways, and in conjunction therewith
(but not without that conjunction) the application of a pair of extra small
wheels, with flanges on their tires, beneath the hinder end of the boiler, with
interposed bearing springs like those of the other wheels, that application
of extra small wheels with flanges conjointly with the said using of large
impelled wheels without flanges, being for the purpose of keeping the engine
straight on the rails when it runs forwards, as well as for bearing up part of
the weight. And also I claim as part of my said improvement, the application
as berein-before described of the pressure of the steam or water from the
boiler, to act-when required in hollow cylinders or pistons, or plungers, which
are connected with the clogs or brakes for the wheels, so as to bring the said
brakes or clogs into action by the pressure of the steam, instead of by the
strength of men, as heretofore done. Note.-I make no claim to the use of six
wheels in locomotive engines, to travel on edge railways, if the impelled wheels

page_text: have flanges, but only when the said impelled wheels have no flanges; and for
the more complete explanation of my said Invention, I have hereunto annexed
three Sheets of Drawings, representing two locomotive engines for the quick
conveyance of passengers and goods upon edge railways, when constructed
according to my said improvement.
Sheet I., contains a side elevation, end elevation, and end section of such
an engine. K, are the main impelled wheels on the cranked axle, without any
projecting flanges on the tires which run on the edge rails; L, M, are the
extra small wheels with flanges applied beneath the binder or furnace end of
the boiler, and O, are the ordinary small wheels with flanges beneath the
chimney end of the boiler, where the working steam cylinders are situated.
The small wheels O and M, with flanges, keep the engine straight on the
rails, as it runs forwards thereon, and the larger impelled wheels K, have only
to advance the engine forwards, and to bear a due portion of its weight, with-
out having anything to do with keeping the engine on the rails, having no
flanges which can hold laterally on the rails, wherefore the cranked axle of
the wheels K, is liberated from all stress by any lateral action of the great
wheels K, against the edges of the rails, and the small wheels O, M, with
flanges (which wheels have straight axles) sustain all the stress of that lateral
action.
Sheet II., contains a separate drawing of the brake or clog which is also
shewn in its place in Sheet I. A, is the hollow cylinder into which a
plunger is fitted, to act by a lever y, and an upright rod f, upon the two
clogs or brakes D, D, which are suspended by pendulous links z, from a
centre pin, or bolt E, fixed to the frame. The clogs or brakes D, D, are
caused to apply to the circumferences of the tires of the wheels K. and M, by
means of links g, 9, which are interposed between the two clogs or brakes D, D,
and which links when put down to an angle as shewn in the Figure leave the
brakes or clogs D, D, free of the wheels K and M, but when by opening the
cock C, the steam from the boiler is admitted through the pipe b, b, into the
hollow cylinder A, it raises up the plunger therein, and that by its lever y and
rod f, draws up the links g, g, towards a straight line, and then they force the
two clogs or brakes D, D, apart from each other against the wheels K and M,
with an encreased force beyond that which the plunger exerts, that increase of
force being in consequence of the leverage at y, and the oblique direction of
the links g, g.
When the handle of the cock c, is turned the other way, it
allows the steam to issue through an upright spout, and escape from the cylin-
ders into the open air.
Sheet III. represents another locomotive engine, such as is now in use,

page_text: but with my improvement added thereto. The foremost wheels at the
chimney end of the boiler are impelled (by means of outside cranks and
connecting rods,) as well as the two middle wheels K, which are on the
cranked axle; in other respects the improvement is the same as in the
other engine represented in Sheet I. The brakes or clogs are not represented,
but if such brakes or clogs are required they may be applied as herein-before
described, and shewn in Sheets I. and II.
In witness whereof, I, the said Robert Stephenson, have hereunto set