The Sun.
London, England, 1846-12-16 00:00:00

The experiments of M. Arnoux, at St. Maud 6, did not
cost less than from 6,0001. to 8,0001. All sorts of obstacles
to locomotion, such as inclined planes ascending and de-
scending, crossing of ways, straight lines joined to curves,
curves in an opposite direction, succeeding each other
without intermission, and also curves of very small radii,
are found in the experimental rail in question, which is
about three quarters of a mile in length, forming a
closed circuit. This arrangement permitted the re-
turning to the point of departure as often as
was liked ithout stopping, thus enabling the
train to run as great a distance as could be de-
sired. All then that remained was to ascertain whether
anything was necessary to be done to test the system of
AI. Arnoux eff..bctually as regarded strength, injury to
the rails, duration of the wheels, and the mechaniim
employed to give the axles the intended and proper di-
rection ; to examine well the effect of curies upon loco-
motion—curve.; of less radius than any engineer would
ever experiencein a regular railroad, viz.. a small circle
of a radius of only IS metres, completely closed, joining
to the principal road (i. e. the closed circuit) by
two branches of curves of 30 metres radius ; once en
tered in the circuit, the train could run over it indefi
nitely.
M. Arago, after having described the nature of the
experimental train, composed of a locomotive engine and
five waggons, examines the system itself.
"The system," he says, " is composed of three dis-
tinct parts." It will be right to point out the effects
of each.

The first—the particular and special means of direct•
ing the first axle of the coach.

The second—the common means of directing the first
axle of each of the coaches that follow.

Finally—the means of giving in each carriage the
same direction which the first axle has already deter-
mined to the axle of the second.

The first means consist, as has been stated, of iron
forks with bent prongs, furnished with small wheels.
These wheels move pretty nearly horizontally, slightly
inclined, inside and out, from top to bottom, and in rol-
ling lean against the edges, or rather against the vertical
sides of the rails. These directing wheels, when they
are well adjusted, experience no other resistance than
that which arises from the rolling, for the axles which
supports them hinders them from ever bearing by their
horizontal surface on the rails. The centres of these
wheels are thus maintained at four summits of a right
angle, between the opposite rails, with a very little
quantity of play.
!Experience has proved the advantages which these
guide-wheels present. They have never shown any ten-
dency to leave the rail, there has been no breaking down
on the route ; the surface, which was worn'rapidly when
made of soft iron, showed no perceptible wear when fur-
nished with circular bands of steel.
A ooze means employed for directing the first axle
,013fiath: 'carriage, they are unexceptionable in a Ream°.

-7

Theo • hich iu ordinary carriages goes tho
11
lig it,:

All tends to the belief," he says in the exposition of
his system, " that in the construction of carriages des-
tined for the railways, enough perseverance has not been
used in searching for the means whence the facility of
movement is derived in the ordinary routes ; too much
pre-occupied with the great work on hand, of which a
part may be regarded as the consequence of the imper-
fection of the carriages, it is thought that the engineers
have neglected to use their endeavours to correct the
imperfection itself, and that they have too easily ad •
mitted the principle of rigorous and inflexible parallelism
of the axles, and in consequence the fixity of the wheels.
I say in consequence, because it is evident that with
axles invariably parallel, the movability of the wheels is
inadmissible, because it would lead teo easily to dis-
lodgement from the rails." M. Arnoux then brings
forward divers inconveniences of the present system,
and points out amongst them the too great approxima-
tion of the axles in respect to the length of the bodies
of the carriages, whereby the latter do not obtain a
true bearing, and as, in consequence of this disposi-
tion, the traction cannot be transmitted but by the
extremities of the frames which bear the bodies
of the carriages, the slightest deviation gives to them
an oscillation which is conveyed from one end of the
train to the other, and tends to give to each axle an
oblique position to the direction of the rails, and re-
quires wheels capable of resisting these efforts, which
are proportionately more violent as the speed increases.
It was in the year 1838 that M. Arnoux presented to
the French Academy the specimen of the new system
which he proposed to apply to railways. This speci-
men was a model, the fifth part of the size of the car-
riage to be adopted, and it is of this model we are
about to speak ; for although the inventor has made
some changes, they are not of a nature to affect the ge-
neral principle.
M. Arnoux defined his system as follows, in submit-
ting it for the judgment of the institute :
The construction of the beds of the carriages will
differ very little from the construction of those of ordi-
nary carriages ; they will consist of a fore and hind bed
resembling each other.
Each axle, pierced by a main iron bolt,* will have
the power of turning horizontally upon it.
Wheels mounted with patent cylindrical boxes, will
have freedom of play on the axles.
The fore and hind beds, of the different carriages in
succession will be united by means of a carriage beam,
which will be pierced by the two main iron bolts that
pierce the axles, and which will support two transoms
(cross beams) upon which the springs will be placed.
The coaches will be connected by an inflexible iron
rod (called a timon), pierced by the main bolt of the hind
bed of the preceding carriage, and upon the same bolt in
the fore bed of the carriage which follows.

The fore axle of the first coach will receive its direc-
tion from the road itself ; to effect this, two irons, each
having two prongs, will be attached to the centre of the
under part of the axle ; the two prongs descending to-
wards each rail, will carry a small wheel (in all four)
which, by slightly touching the rails, will, without effort,
give to the axle the right an,gular direction to the road.
From this fore axle the symmetrical direction will be
communicated to the hind axle of the same carriage, by
means of two chains, one crossing the other and the ends

of each fastened to two circular crowns (one fixed on
each axle) of equal diameter. Each chain, as it may he
so called, consists of a long iron rod in the centre, with
hooks at each erd, to which are attached pieces of chain
that are fixed to the crowns. The form of these chains
when fixel may be compared to the section of an hour-
glass in a horizontal position, in fact somewhat like the
figure 8.

From the first to the second coach the traction will be

effected by means of the inflexible iron rod (amen) be•
fore mentioned ; the direction will be communicated to
the fore axle of the second coach by similar cross chains
as above mentioned, which passing from a crown fixed to
the carriage beam of the first coach, and pierced by the
main bolt of the hind bed, to a crown of double diameter
fixed to the axle of the fore bed of the second coach, and
in the same manner fastened by the main bolt.
To communicate successively the movement to all the
axles of a train, and to make them converge, the one
after the other, towards the centre of the curve, it is ne-
cessary to be understood that the beam of a carriage will
not change its direction, except when the road itself
changes it; thus in determining the relation which exists
between the angle whi•:h the beam describes in each
change of direction, and the angle that each axle de-
scribes also, to pass from the first to the second direction
without ceasing to be at right angles to the route, the
convergence of the axles of any coach whatever may be
obtained by the direction of the beam of that which pre-
cedes it.

The question, in this state, was the subject of a special
report to the academy, which, in acknowled4ing the im-
portance of the proposed solution, expressei a wish that
the system should be tried to prove its value, and to re-
move, by practice, certain apparent objections.
M. Arnoux set himself immediately to work, and in a
little time invited the academy to see, not only a theory
and models, but a practical system at work on an actual
railway.
It was at St. Maude where tha experimental railway
was made, and the examination of it confide :l to a com-
mission, of which M. Arago, the Astronomer Royal, was
at the head.