AMERICAN ENGINEER Vol. 87, No. 1,
change for a reasomalite number of years rather than to redesign
each new lot ordered. The intal cost of maintenance is cfccied
very materially by the number of diferen types and classes in
usc. Furthermore, as was mentioned by Mr. Vaughan in dis-
cussing this feature, the motive power of a road having standards
is much more flexible and can be shifted from one part of the
system to another without raising the cost of repairs and without
crippling the service due to bolding an engine in the shop while
awaiting the arrival of some necessary part. It has been the ex-
perience of those roads that have gone ima standardization of
motive power most extensively that there need be no reduction of
development or experimental work, but that it has been necessary
and normal to add a new type or class to their classification every
three or four years which, however, will use many of the parts
common so cther locomotives. It seems that the principal differ
ence between those roads provided with complete standards and
others not so provided is that the former spend several years in
experimental and developunen: work and anally determine on a
horoughly well fitted design which is decidedly larger and mune
powerful than the previous standard engines for the same service,
while the latter, meanwhite, may have purchased a number of
different designs each of which may have been best suited for a
particular condition existing at that particular time, and at the end
of five or six years they have comparatively small mmbers of
many different classes scattered over the system. From the stand
point of net cost of furnishing transportation it would seen that
the standard locomotives which are best suited to the average
conditions of service will prove better than those which are es-
pecially designed for scine local condition which may change even
beiore the engines have passed their first shopping. In speaking
of standard locomotives in this connection it is not to be inferred
that a standard design is inviolable simply because it is standard,
Int it does imply that only such changes are to he made in which
the new design will replace a part in such a way as not to affect
the other standard parts,
One of the notable events of the year in locomotive design is
the demonstration of the possibilities of the Atlantic type loco-
motive by the Pennsylvania Railroad. The experimental engine
built for this purpose carries the largest weight per driving axle
of any in this country. But, as was pointed out by Mr. Gibbs in
the discussion, it is not the static wheel load alone that shemd he
considered, bm the dynamic plus the static. If the weight of the
reciprocating parts can be sufficiently reduced there is no objec-
tion to raising the wheel load. W. F. Keisel, Jr., u lis discus-
sion stated that it will be possible to use a weight of 70.000 lbs.
per pair of drivers if the weights of the reciprocating parts are
sufficiently reduced. A number of years ago the Master Me
chanics Association adopted a rule for counterbalancing: pro-
posed by G. R. Henderson. in which it was stated that the
equivalent of the weight of the locomotive divided by four
kundred, in weight of reciprocating parts, could be left unbalanced.
If the counterbalance weights on each pair of wheels are carefully
weighed this rule is satisfactory. It was stated by Mr. Keisel that
one pound of reciprocating weight to each hundred pounds of
maximum piston pressure is within the bounds of possibility.
This, in connection with Henderson's rule, for Atlantic type leen
motives would permit the use of counterbalances for reciprocating
parts equal to one-third their weight. If this point is reached a
weight of 70,000 lbs. per axle will put an more strain on the rail
than is induced by the heavy Incomotives now in service where the
counterbalance weights are generally two-thirds of the weight of
the reciprocating parts.
While the experiteemal locomotive does not quite reach this
weight per driving axle, it carries an coueaally large hoiler having
tubes 13 1.9 in. in length and is fitted with a high degree super-
heater. On the testing plant it gave a maximur. indicated horse-
power of 2,355, and when operating at a horsepower of over 2,000,
a minimum steam consumption of 16 lbs, per horsepower hour
was attained. The maximum equivalent evaporation of the heiler
was I lbs. per sq. ft. of heating surface per hour. These tests
insticate the possibility of one horsepower per 100 lbs. of weight.
or for 1 sq. ft. of heating surface at 80 miles per hour. The
results from this locomotive indicate the better engineering
which the past year has shown is beginning to be applied to the
locomotive as a whole. Locomotive No. 50,000 designed by the
American Locomotive Company, was a revelation of what could
be done with a Pacific type by careful attention to proportions
and of better engineering in the design of various parts. The
Atlantic type on the Pennsylvania goes a step further in the same
direction. With these as an example it is probable that the com-
ing year will bring forth further surprising results in the capacity
of locomotives that are within the normal clearance licnits,
It is hut heginning a be understood how little is really known
of the processes of combustion in a locomotive and the ways of
improving it. The firebox end of a locomotive presents a rich
field for investigation. With all these possibilities of improve-
meat in mind, the difficulties of determining the design of a
series of standard locomotives are great and in preparing the
designs it should be kept clearly in mind that it may be desirable
to replace various parts or even a complete boiler within a few
Cars. Stel alteratious, however, hy ne means imerfere with the
maintenance of the standards as the term should he applied to
locomotives.
NEW BOOKS
Master Car and Teromotive Painters Association. Troceedings of the 1912
Convcution. Bound in cloth. 308 pages. 6 in. x 9 in. Published ly
the Master Car and fanomotive Painters' Assoriation of the United
States and Canada, A, T. Dane, Secretary, Reading, Mass,
The forty-third annual convention of this association was held
in Denver, Colo., September 10-13, 1912. The most important sub-
jects considered were the Finish of the Vestibule Ends; the
Report of the Test Committee, which contained valuable in-
formation on hepentine substitutes; the Essentials of a Protective
Paint-Making Oil: the Use of Interior Car Renovators; the
Most Economical Method of Removing l'aint from Locomuctive
Jackets; the Care of Steel Passenger Car Roofs: the Treatment
and Finish of Passenger Car Floors; and the Modern Method of
Exterior Passenger Car Painting.
Juvestigation of Explosion Proui Motors By II. II. Clark. Mustrated.
Teund in cloll: 44 pages. 6 in. x 9 in. Published hy te lereau of
Mines, Department of the Interine, Washingen. D. C.
This pamphlet contains detailed account of the apparatus used
in the tests and the method of testing motors to determine their
tendency to cause mine explosions. The term "explosica proof,"
as applied by the Bureau of Mines to an electric motor, refers
to a motor enclosed by a casing so constructed fitat an explosion
of a mixture of nine gas and air within the casing caused by
a spark in the motor will not ignite a mixture of the same gas
Surrounding the motor. Various mixtures of gas were used in
the test under various pressures and explosion indicator cards
are shown for a number of the tests.
Hygiene for the Workers. By William Tohman, Ph.11.. Thrector Ameri.
can Museum of Safety, New York City, and A. W. Guthrie, Depart
ment of Research, American Museum of Safety. Illustrated. Bom
in cloth. 331 pares. $14 in x 7% in. Published by the American
Book Company, New York. Price, 50 cents.
This book is thoroughly practical. In addition to the general
topics treated, such as clothing, food and excreise, the subjects
of alcohol, tobacco and anti-tuberculosis measures, home hygiene.
and the particular necessities for cold and het weather are ena-
sidered. The work is divided in 19 chapters, which not only
deal with the clothing, cleanliness and generai good health from
a hygienic point of view, but also from the inherent value it is
to a person in the business world. Among the characteristic
chapters are: Applying for a l'osition. Good Habits for the
Worker. Food and Drink, Hygiene of the Work Room, After
jours, Choice of an Occupation, First Aid to the Injured, Season
able Hygiene, etc.
