The Sun.
London, England, 1863-11-19 00:00:00

A Safety Locomotive for Sharp Curves.

Mr. Cross, the engineer of tke St. Helen's Rail-
way, Lancashire, has been tor some time occupied
with the construction at the company's
new class of engine, the result of which in practice
datum in railvvay
so well corresponds to sound theory that it is likely
to exercise a material influence on the structure of
new railways, by the substitution of sharp curves
for tunnels in mountain regions, and also for facili-
tating junctions between lines and the entrance into
cities and towns.
consrtoruunctdio
It is a works of a
fact seldom adverted to that the governing
the engine for
or inclines. passingßith ter o, the construction of engines
curves ri sv
etshaen de capacity
ei
gradesty o f
has only adapted them for running with free
roll-
ing movement on straight lines,
even when accu-
rately made, and only capable of running
on curves
by dint of grinding or sledging friction of the wheel
tires. To diminish as Snuck as possible the amount
of this friction the practice has been to keep the
engine as short as possible—i.e., the axles as close
together as possible. The result of this has been
an unsteady base and a topheavy superstructure,
liable to constant oscillation from two affecting
causes—the alternate motion of the pistons on the
crank and the irregularities of the rails. On curves
binding the rails closer to the wheel flanges the
oscillation would ba less, but the grinding friction
would be more, and the greater the risk of the
wheels escaping from the rails in case of a sudden
impediment or a deflected rail. The enormous
weight of the engines has tended to counterbalance
this risk, but at the cost of greatly increased de-
structive wear.

The St. Helen's line, miming through a hilly
mineral district, is a remarkable sample of sharp
curves and gradients. In a length of about 30 miles
it has a constant succession of curves, varying from
500 feet radius down to 170, and it has gradients
from one in 85 to one in 35, and it has, moreover, a
large number of " points and crossings" opening
into the various mineral deposits. This line has
been usually worked by short engines on six wheels
with four coupled wheels as drivers, and connected
to separate tenders for the supply of fuel and water,
the length of the wheel base of the engines being
about 12 feet. Even this comparatively short length
of engine was disadvantageous on curves, involving
much impedimental friction ; and a still greater
disadvantage was that tender engines are only
adapted to run safely with the tender behind, and
in the working and shunting the loss of time and
labour, and expense, was considerable. For this
reason Mr. Cross set about the construction of an
engine that should be capable of running freely and
without impedimental friction in a straight line,
and either end foremost, and also pass with free
rolling movement round curves of as sharp a curve
as a radius of 132 feet, or what engineers call two
chains. To say that it was pronounced impractica-
ble by men of routine is merely to say that it was
out of th© category of most working improvements.
The engine is on eight wheels, covering a base of
22 feet in length, and the length of a solid frame
resting on it 32 feet. The four central wheels have
their axles passing through before, and behind the
engine fire-box as usual, the axles being about 8 feet
apart. It is obvious that so long an engine
could
scarcely pass round curves at all, even at any cost
of friction, with the ordinary construction of wheels
and axles. The difficulty is obviated by a very
simple
four
pro process.
ess.
The
central
parallel to each other. Consequently, in the ordinary
mode of construction, they could not move in a curved
line without a good amount of impedimental fric-
tion. This friction is avoided by a very simple pro-
cess of construction. The
wheel tires are applied on
hoop springs
of elastic steel placed between the
wheel On these springs the tires can slip
or revolve andolve ti
without sliding on the rails, and thus the
revolutions of the tires are adjusted to the varying
length of the rails on curves by self-action. This
sliding
of the Wheels on the tires is not found is
any way to impede the tractive power of the en-
gine, but the contrary. The extreme wheels at
either end have their tires applied in the same
mode, but
another movement is also supplied—the
axles have
very
which long bearings, and the boxes in
they run, instead of being parallel to the
axles, are formed in curved lines struck from cen-
tral points, and are permitted to move
in this cur-
vature through the hornplates and asi
Onv-gui-A ss
•be-
neath the spring shoes. The result of gis that the
of
wheels and flanges are free to follow the
coursecrves,
with the very important advantage the rails both on the straight lines
and ° curves,
with a point of
carves' always
safety that the extreme axles
point truly to the centre of. though the
conse-
quently are square to the rails,
S, requiring the axle
curve may be in the form a
of
directions.
There is, axle
to radiate in opposite theecovnnerhve, and
wheels to escape from the
traight lines, and though
fore no tendency in the
rails either on curves
radii,or straight
the great length of pie
adapted to such small
trols the action of the pistons
frame governs and
the wheels are deprived f
ral oscillation, while
by the removal'cif
their the cranks, and. preventseee both vertical and late-
ral of
their vicious irregularity
friction, and the wear thy.
and
is reduced to th ' e minimum.
tear of tires and rex . .
ocess is simple for rendering
osu s
Thus, the pr . heavy
co'stly and danger.
powerful engines practicable by increasing
and
their wheel base, and distributing the load for the
ascent of heavy gradients. A mountain side mays
thus be traversed by a series of zigzags, like tho
of the old horse paths, and narrow and tortuouse
valleys may be threaded along the course of
tain streams. The highlands of Scotland moun-
Wales, of Derbyshire and the Lake and of
, the
mountain regions of Italy, Switzerland,
are all within the reach of a cheap system and Spain
locomotion, dispensing with eaP sYstem of steam
costly tunnels and pro-
tracted periods of time; and it becomes easy to deal
with the streets and roads of
a powerful engine capable
of townslarge and cities, when
speeds can move freely loads and t igh
of the 0 xford-stree t round a curve similar to that
circus.
If any of our
Helen's
line and judge for themselves where they
will find an engine, not
a principle capable'but with. merely not costly,..
Hitherto, engines
been well
has of adaptation to existing stock.
_ for lines. of sharp curves have not
adapted to high speed, but that difficulty
ceased. The same engine may traverse the plains
and make its journey through—or rather over—the
mountains with equal facility, with the exception
that it cannot carry so heavy a load uphill as on the
plain. And it has the additional advantage that
the blending a sharp curve with a steep ascent—the
most difficult of all railway problems under present
circumstances—will in noway interfere with flee
rolling movement, or absorb 6t n y po v ,e r beyond that
L due to gravitation and axle friction., —Tirncs,