The new Northwest. [volume] (Portland, Or.) 1871-1887, 1873-08-01
Compressed Air as a Motor on City Rail-
roads.

portant and interesting subjects TO the
people is that of Improving upon and
cheapening the motor powers used for
propelling cars on horse railroads.
Horses are expensive and slow; the
dummy engines hitherto used are noisy
and in some respects dangerous. Our
attention has been called to new in
vention, whereby it is claimed to be al
ready demonstrated that compressed air
can be employed as motor power with
more efficiency and economy than any
other agency yet employed. Some of
the statistics and experiments are
rather startling. The inventor of this
new machinery is the well known HOr-
ace H.. Day, of New Iork-nOw, how
ever, temporarily residing in this city
and it is claimed not only by Mr.. Day,
but by scientific engineers and practical
mechanics and railroad men that Mr..
Day has really perfected n system of
rapid transit, which enables him to
transport, by the agency of compressed
air, 81 passengers u miles at a cost for
fuel less of than 10 cents for the whole
distance. He is getting up companies
to apply his patents throughout the
cities of the United States. The follow
ing card, with the estimates of his engi-
neer, will be read with interest:
THE COST OF COMPRESSED AIR oN CITY RAIL
ROADS As SUBSTITUTE FOR HORSES.
NEW YORK, July :, 1878.
In response to a request from Mr.. /
Beach, of the Pneumatic Railroad Com
pany, for the estimate of the cost of fuel
for running my air power ear on his
proposed road, Ireported from twelve to
sixteen cents per hour as the certain |
outside limit of the cost to run a car |
seating fOrty-four passengers. This re-
port was deemed too indefinite, and |
likely to be far inside the actual cost, |
and he calls for the elements of calcula- |
tion, whereupOn my engineer has called |
upon Mr.. Beach, and now furnishes the |
following report, which l print for the /
editication of all concerned, renewing
my own conviction that can perform
more than double the service; that is, |
can, by the adoption of my system of
rapid transit, transport double the num-
/ Ter of passengers upon the Greenwich
Street Elevated Railroad, with cars
/ leaving each station every five minutes)
than can be done by steam as now used,
without increasing the aggregate cost.
1t will require but superficial calculation
to show that the air power would not
reach One-siXth of the cost of horses, for
the transportation of like number of
passengers, now moved by horse power
on ordinary city railroads, and the
engine by which this can be done is the
newly invented "Manley Engine"
which weighs less than 80 pounds, and
works air expansively, in a manner bet
ter than by any engine ever before
built. HORACE III. DAY,
81 Liberty street, New York.
Engineers Dept, Compressed Ai)
POUer Co., DeLaDldter Iron Works,
NeI0 York, July 3, 1878.
Assuming a car with its passengers
and machinery at twelve tons, moving
u miles per hour, or 1876 feet per
minute, the tractive force at 10 pounds
per ton equals l20 pounds, then 120X
1856. $4,000 equals S.S4 horse power,
actual duty; if we now add 20 per cent.
for loss of engine or Is of 3.S4, it will
stand as follows: 3.S4-5 equals AZ, and
3.S4X77 equals 4.6l engine power, in
cluding its own friction.
If we take Mr.. Beach's estimate that
it will require six times this power to
pump the air necessary to drive the car
engine of u tons inclusive, then 4.6lX6
equals 27.66 horse power, say 2S horse
power, and 2S horse power obtained by
an expansive high-pressure engine,
non-condensing, no steam jacket, using
pea coal at 81 90 per ton, will not eX-
ceed 2.75 pounds of coal per horse per
1 hour, 2.75X2S equals II pounds, and
224O.77 equals %, and 81 so the cost
/, price of q ton of pea coal divided by %
equals S.62-l00 cents per hour, as the
cost of running q car of IL tons, as above,
at 10 miles per hour. Note-an engine
which / put up worked regularly with
out exceeding this cost per hour, high
pressure, expansive, and no steam
Jacket Mr.. Beach admits that Eng
lish high pressure engines, with steam
, Jackets, have not eXeeedeSbEtwo pounds
/ of coal per horse power per hour, and
: maintain that high pressure, expansive
and condensing engines with steam
: Jacket can be made to do full duty, year
after year, burning pea coal and not eX-
! ceed one and One-half pounds of coal pei
/ horse power per hour.
a BY Royce's mode of COMPRISING air
q the loss resulting from the heat OF com
. preston necessarily must be greatly
diminished. With surface Refrigerator
> and abundance of cold water, and the
8 condensation being effected at two oper'
I ations, the saving from loss should bS
: double that resulting from compression
4 with one cylinder only, and if the com
4 press is accomplished at three opera
; tions, then the loss resulting from hea
n should be three times less than the los
a from one cylinder, and this loss by hea
q being the greatest of all losses to cOntenI
y against. 4 great saving of power mus
. result from this mode of compression
# by careful experiment only can tn
n amount of this saving be correctly de
m termined, but it may be roughly esti
i mated that at least two-thirds of tn
loss resulting from heat may be save
r by this means. Taking this view, be
o lieve that the compressed air belnl
J. worked expansively lthe inverse of com
N pression), that 20 per cent. would be al
: ample allowance for loss from heat =
n per cent. would be also ample for loss II
% air engine driving tie car, and 10 pc
!, cent. for leakage and stoppages, maxim!
y a loss of so per. cent. altogether there
:, fore it would reasonably appear ina
: a good engine with every advantage
~ running constantly and doing dutl
of 10 horse power, should compress sum
cient air 10 run q Il ton car. But II
=, order to have safe margin 10 NEE
= every contingency OF stoppingi starting
. and increased friction on lhcilhe'
planes, and possible extra ieaKages iron
eareIessness. / would prefer an engin
" capable of working at the hlghest ad
ii vantage ND to % horse power, and no
- o~ceedinp II pounds of coal per hOrs
- nower per hour, or 81 pounds of coal pc
~ hour altogether, which, at S2 so pc
is ION. would be 4.lS-l00 cents per hour, a
? total cost Of fuel to run a y ton car DC
" hour.
n FIVE now contrast this with the praC
IN tice hitherto adopted, viz: compressor
i the air with a common non-eXpansiv
re engine, consuming at least to pound
D. of coal Der hour per Fl p or from