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Y2 THE COAL TRADE BULLETIN.
THE TESTING OF LOCOMOTIVE FUEL/ 1
By F O. Bunnell. Engineer of Tests. Rock Island Lines.
It is gratifying to note that many railroads are
giving the fuel question more serious consideration
both from the standpoint of fuel and type of furnace
used and b.v various tests of fuels such as
tests between coal taken from different sources,
coal as compared with oil, briquetting bituminous
and lignite coal, evaporative efficiency under different
boiler conditions, etc., they are gradually
adopting the fuel most practical to use in a given
territory and boiler conditions adapted to greater
evaporative efficiency. There are many reasons
for this activity on the part of the railroads,
among which, with a brief explanation, are the
following:
A. Prof. Goss has estimated that in the average
locomotive furnace 20 per cent, of tlie total fuel
supplied to the locomotive performs no function
in moving the train forward. Adding to this the
losses due to radiation, adhesion to the rails, flange
friction, etc., it is estimated that not over 5 per
cent, of the latent heat value in the coal performs
useful work in moving trains forward. In 1906
out of 90,000,000 tons consumed, it is estimated but
40,000,000 tons represented heat actually transmitted
from the furnaces to water to be evaporated.
Accepting the above figures as reasonably
accurate, it is obvious there is urgent need of improvement
first to utilize a greater percentage of
the heat in evaporating the water, and second to
reduce the losses of the resultant energy. There
are certain conditions now existing on all railroads
fixed by the type of locomotives now in use,
in wdiich there can be an excessive use of fuel unless
the furnace conditions are adapted to the fuel
or the physical character of the fuel is adapted to
the type of locomotive in which it is used, or if the
fuel is of inferior quality.
B. The fuel bills of a railroad occupy the most
conspicuous part of the total cost of operation, in
many cases amounting to 13 per cent, of the total
cost of operation and 26 per cent, of the total transportation
expenses; while these
FIGURES WILL VARY,
with different railroads, according to the kind of
traffic handled, in glancing over the report of
transportation expenses of the A & B railroad the
item of fuel for locomotives amounting to about
$6,600,000 stands out in bold comparison with any
other item and with the total cost of transportation
of about $25,000,000. In years past there has
heen marked attention paid to the cost of lubricating
oil which, in the statement referred to,
amounts to about $106,000.
C. It is a well known fact that there is a vast
difference in the evaporative efliciency of fuel as
obtained from the different localities and frequently
between two sources in the same locality. For
example the average range of heat units in locomotive
fuel might be stated as follows:
Fuel oil. from 15,800 to 20,200 B. t. u.
Anthracite coal, from 12,900 to 14,700 B. t. u.
Semi-bituminous coal, from 14.500 to 15,500 B.t.u.
Bituminous coal, from 8,500 to 16,200 B. t. u.
Briquettes - , 200 B. t. u. more than same grade
of coal.
Fuel is no longer fuel in the sense of the pioneer
indiscriminate use of this utility, and while it is
evident, from the above range in heat units, that
fuel cannot always be used, with economy, on the
basis of geographical location, attention is also
called to the fact that the smallest range of variation
per pound of fuel, as shown above, is 1,000
heat units for semi-bituminous coal or 7 per cent.,
and no railroad can afford this variation in its
fuel hills without challenging the cause for same.
D. There is also a great difference in the physical
nature of the fuel; fuel oil varies in viscosity
and specific gravity as well as in the flash and fire
tests. Coals vary in specific gravity, hardness,
I rittleness and tendency to crumble on exposure
to the atmosphere. The character and quality of
the ash of coals is also important: some coals have
comparatively little ash and give no trouble from
this source, while others have a large amount of
ash. 18 per cent, in some cases; sometimes the ash
clinkers badly or forms a semi-flux which on cooling
has been known to practically seal tlie grate
bars. The character of the ash made is frequently
more important than the volume.
To use fuel to the best practical advantage, in
addition to the factors already mentioned, attention
should be given to the difference in the physical
nature of the fuel. The
RATE OF I'RODfCIXG
steam and the cost of same in a locomotive with a
given furnace and front end adjustment are extremely
sensitive to a change in the physical character
of the fuel; is is, therefore, advisable to
use fuel of the same physical character, on a railroad,
over as wide range of territory as possible
and it is equally important to insure that the socalled
draft arrangements in all locomotives are
carefully adjusted to burn the fuel to the best
advantage in evaporative efficiency.
While the above explains the reasons for the
activity shown by most railroad managers in in­
'"Paper read before the meeting of the International Railvestigating fuel conditions, it also serves to emway
Fuel Association.