This locomotive is well adapted to the
miscellaneous service required in outlying districts where a
narrow-gage track, sharp curves, inexperienced operators, quick
firing, ruggedness of construction, interchangeability of parts,
over all height above rail, may all be factors demanding
consideration. It would appear from the manufacturers' claims that a
favorable answer might be given with respect to all these points.
geared steam locomotive works
The locomotive stands on a short 4-wheel
base. This provides for the negotiation of sharp curves. Above
the main frame, the locomotive may be divided into five
principal compartments. At the forward end is the water tank.
Next back of it comes the smoke box, then the horizontal tubular
boiler, then the firebox, and finally the driver's cab. No
tender is required. A tank in the cab provides for the storage
of liquid fuel. It may be gathered from what has now been said
that the locomotive is driven by steam, and that the firing is
done by means of fuel in the form of liquid. The fuels possible
seem to be pretty much all that have received commercial
recognition—gasoline, kerosene, fuel oil, etc.
The Bell Oil-Burning
Locomotive
It is pertinent
to point out that in general a steam boiler may be much more
quickly gotten into actual condition to drive the engine where
liquid fuel is used than would be possible with ordinary solid
fuel. The reason is largely this: Oil fuel is used in the form
of a spray consisting of small particles intermingled with air.
Because of this mode of using the fuel, a great deal of fuel
surface is instantly in reach of air necessary to its
combustion. The flame reaches everywhere and right away. With
ordinary solid fuel in lumps and sticks, there is only a limited
total of surface affected by the flame at the beginning. It
takes time to get the normal total of surface into a highly
heated condition. One of the liquid fuels
mentioned—fuel oil— has, for a number of years, been widely used by
ordinary public steam railroads. Fuel oil has also gone into
extensive use for the firing of steam boilers on naval vessels, both
in the United States navy and elsewhere. Fuel oil is also in
considerable use for the firing of steam boilers in shops and the
like.
geared steam locomotive works
The engine of the Bell locomotive is,
as already intimated, a rather simple piece of apparatus. Its
fifteen moving parts operate in oil within a suitable case. The
engine and its case are carried forward of the front axle and
beneath the main frame. All the parts are said to be drop forgings.
The case includes within it the axle gear. The engine is rigidly
bolted to the case, the latter being arranged so that it pivots on
the front axle. The forward or cylinder end of the engine is hung
from the main frame by a flexible steel strap. Because of the
foregoing arrangements, the engine and axle gears are not
disturbed in their proper engagement with each other by movements of
the engine. The case is tight in order to prevent the leakage
of oil and the entrance of dust. The stuffing boxes are so
arranged that they may be adjusted or repacked without disturbing
the case or the engine.
The boiler, as already said, is of the
horizontal, tubular type. The shell, including the firebox head,
consists of a single piece of metal. The smoke-box head shell
and ring are welded together. The tubes, which crowd the
cylinder, are welded in on the firebox head and expanded into
the openings at the smoke-box head. The entire boiler may
readily be replaced by another when necessary. The flame or
flames from the oil apparatus are so directed as to give the
major part of the heat to the tubes in the lower part of the
boiler—that is, to the tubes below the water level—and a minor
part of the heat to the tubes near the top. The tubular
construction naturally favors quick firing because of the great
surface of contact with the water on one side and with the heat
on the other. The shell of the boiler is given added strength by
the use of a number of layers of piano wire, this wire being
tightly wound in place. geared
steam locomotive works
The main driving boxes are rigidly
secured to a pair of steel bars which parallel the side bars and
lie under them. The main frame bars rest on four elliptic
springs. These are secured to the side bars of the sub-frame.
geared steam locomotive works
It will be of
interest to have before us some details as to sizes, capacities,
etc. All sizes of this type of locomotive have a uniform height
of 6 feet. In all, the wheel base may be 3 or 4 feet in length. The driving wheel size is uniform, being 20 inches in diameter. The boiler pressure is likewise standardized at 325 pounds per
square inch. The width for all locomotives depends, in part,
upon the gage of the track. Where the gage is less than 36
inches, we get the width by adding to the gage 28 inches. Where
the gage is 36 inches or more, we add to the gage 14 inches. Thus, for a 30-inch track gage, the width of the locomotive
would be 58 inches. For a 44-inch track, the width would be
precisely the same; but for a 40-inch track, 54 inches. The
over-all length varies from 11 to 14 feet. The minimum curve
that may be negotiated naturally turns on the length of the
wheel base and the gage. The two smallest locomotives are
capable of getting round curves whose radius is no greater than
14 feet. The four biggest sizes can manage curves of 16-foot
radius. These are claimed as possible, but are not especially
advised. If we double the least possible radii, we shall get
those corresponding to fairly comfortable curves. The smallest
locomotive, with a cylinder size of 3 1/4 inches diameter and a
stroke of 4 1/4, will weigh when in working order about
6,000 pounds and is said to have a tractive power of 1,000
pounds. The largest locomotive, which has two engines, each
having cylinder size of 4 1/2 x 6 1/2 inches, will weigh in working
order some 24,000 pounds, and will, it is said, exert a tractive
effort of 6,000 pounds. On the level, a tractive effort of, say,
30 or 40 pounds, will be required to pull one short ton in the
form of a loaded train. Taking 35 pounds as a fair average, the
smallest of the locomotives, with a traction strength of 1,000
pounds, would be able to pull 28 tons of train. The biggest
locomotive, with its 6,000 pounds of tractive strength, would be
able to pull a train weighing 171 tons. Naturally, the weight
that can be pulled up a grade will be less. The smallest
locomotive will, it is said in effect, be able to pull 11 1/2 tons
up a 2 percent grade, while the biggest locomotive will, it is
understood, pull up the same grade 73 tons. For a 5 percent
grade, the capacities would be 5 1/4 and 34 tons. These weights are
exclusive of the locomotive. geared
steam locomotive works
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