Evening star. [volume] (Washington, D.C.) 1854-1972, 1897-09-07
AIR MOTOR TESTS
Report Of Engineer W. A. Mcfarland
of Recent Inspections.
SYSTEM As OPERATED IN new YORK
Experiments Made With a Similar
Machine on lexington Line.
THE COMPARISONS
rs MADE

Engineer w A. Mcfarland of the Dis
| trict engineer department. who was recently
| in New York making a second inspection
| of the air motor system as developed there
| in the propulsion of street cars has made
a written report of his observations, and in
addition, has giver a statement of the re-
| suits of a late test of the same system as
| operated over the lexington and Soldiers
Home route in this city.
The report is addressed to Engineer Com
mission-r Black, and is as follows:
In accordance with verbal instructions 1
| have the hoaor to submit the following re-
port on my inspection of the compressed
air motor cars now in use by the Metro
poiitan Street Railway Company of New
York city, and also of those formerly used
| on the 12Jth street line
At the time of my visit, August 10. 20
and 81 there were two compressed air cars
ntted with Hoadley-knight compound mo-
tors, on regular day service between Lem
OK avenue and 146th street, and 10th street
anu CoIumbuS aVenue-the route followed
oelhg LenoX avenue to 10th street to
Manhattan avenue, to 109th street, to CO.
lumbuS avenue.
Similar to No. 100,
Ihese cars and motors are the same in
all essential respects as the No. 4Oy', now
In use In this city. They are run in he
tween the underground electricsr with
which the line is equipped
The total length of run out and back is
SAID to be five miles, with maximum
grade of ~ per cent on lO9th street and
a grade of about 3 per cent on Manh,t1an
avenue. Time occupied in making round
"Trip was 36 TO 10 minutes: time for re
charging with air. two minutes; for re-
heating water in heater ten minutes tba
pipe used for intrndnpipp ba
heatlnS being small, and said to be a tenn
Porary arrangement only. The time need
ca Tor reheating can, without doubt, be
much reduced by rearrangement in his
particular ~ 'i''
Each OF the two cars in use makes about
a dozen round trips per day, and during
the time of my observation carried pas
sengers, made the usual number of stons
maintained speed without difficulty apI
climbed the steep grade on 1G9th street at
a rather better rate than did the electrics
Inc passenger traffic was light, and the
weather favorable. The ONLY point which
seemed open to criticism from the ma ssen-
ger point of view was the putting sound
from the exhaust, which was quite notice.
able IN starting and in climbing grades, but
Whlch could not be heard when under
iedoWay on comparatively level track
Full of Pressure.
The following statement. showing fall of air
pressure on each of the two cars inspected,
!stfng conditions:
No. 411-Initial $500; at end of two and
half miles. 1,6J0; at end of five miles.
Loo. Total loss. 1900 reserve 1.3OO.
Greatest possible run, ten miles.
NO 426-Initial, 400; two and a half
ailieS' i,o'o; nve miles. 1,G25; ten miles, 800.
Iota! loss pressure, 1,5OO; reserve, 800.
Greatest possible run, fifteen miles
Inc difference in fall of pressures on the
two cars is due to the greater reservoir
capacity of 1876 va
In addition to the two cars at present in
l4btn street intended for this service. two
OF them being already equipped with the
Neutrality-suspicious. motors.
Piping a Conduit.
Ihere is line of extra heavy one-inch
iron pipe laid in the electric conduit along
the above named route, for recharsing the
cars at the southern end of the line. if nee
essary; this pipe line was not under pres-
sure at the time Of my visit, and / was
informed that 1t had not been during the
past summer. There is, however about tn.
power house at 146th street a considerable
amount of one-inch and one-and-a-half-
inch pipe under pressure (gauge) Of 26OO
pounds per square inch. An inspection of
some four or five hundred feet of this pip
ing tailed to disclose any evidence of leaky
joints l was assured by several employees
about the station that no trouble from
III.
is said to be ordinary commercial ..heayy''
iron pipe. and is connected up with tight
joint fittings.
The street cars fitted with the Harde
compressed air motors, which We're for
merly useC on 18th street, have been with
drawn from service, and at the time of my
visit were in the car barn on 125th street.
Motors Are Simple.
The motors are simple mot compounded.
with inside Cylinders and outside cranks.
the connections between the main connect
ing rods and crank pins being through the
medium of rocker arms and rock shaft
AL! working parts are close to the roadbed
and exposed to dust and dirt. There are
said to be over 100 wearing parts so ex-
posed, each requiring separate fabrication.
Mr.. Hardfe, the inventor of the motor,
operatec one of the cars for short dis
lance back and forth on the track in the
car track, and demonstrated the fact that
the motor and car were under excellent
control; size of cylinders, seven by four
teen inches. The cars are shorter and
lighter than those fitted with the Hoadley-
Knight motors. and used by the Metropoli-
tan Street Railway Company. The line on
which the cars were used is practically
level except for one short steep grade;
length of round trip, four and ope-half
miles.
The Claims Made.
The following claims are made for these
cars by the American Compressed Air
Power Company:
A mileage of over 10000, with practically
no breakdowns, and with a cost of MAIN
tenance of only " cent per car mile.
consumption of from 369 to 400 cubic
feet of free air per mile.
That cars ran during heavy snow and
sleet storms, when other surface lines
were tied up, with an increased air con-
sumption of only 20 per cent, and an in
crease of 20 per cent in number of pas
Sengers carried.
A hasty inspection was also made of the
Hardie locomotive used in making tests on
the Manhattan elevated railway, and of
the compressor plant on Greenwich street
used in connection Herewith. From this
plant to the Rector street station is a pipe
line about $50 feet in length and 81 inches
internal diameter, used for conveying air
from the compressors to the locomotives.
This line was under a pressure of $50 at
mospheres, or about 300 pounds per
square inch, and showed no signs of leak
age. The line is suspended from the ele-
waited structure and is everywhere in sight.
1t is also connected up with the tight joint
fittings mentioned above.
1t is claimed by Mr.. Pettee, engineer of
the American Compressed Air Power Com
pany, that the cost of COMPRISING LOCO
cubic feet Of free air to 1900 pounds gauge
pressure, at this plant is 275 cents.