Evening star. [volume] (Washington, D.C.) 1854-1972, 1884-05-24
FIVE MILES THROUGH BEDROCK.
Progress Of the Work ON the Subter.
fanean AQueduct.

fanean AQueduct.
MACHINERY Used IN PIERCING THE RoCK-coA-
PRESSED AIR TO BIZ CARRIED TEN NILES
THROUGH PREs-wHAT CAN BE SEEN IN THE
INSTRUMENTATION OF THE UNDERGROUND
OPERATIONS, ETC.
The pufang Of an enormous engine that Is
heard all through the quiet hours Of the night
In the city latterly is the heavy breathing Of q
mighty engine which supplies motive power for
the work In the new water works tunnel Day
and night this huge steam monster pufs away,
stopping only for the "a hours Of Sunday. The
work OF boring a tunnel through solid rock
many feet under ground, from the distributing
reservoir, mile or two above Georgetown, to
the site Of the proposed large reservoir, near
Howard University, is now progressing quite
rapidly. This tunnel is to be II by ~ feet and
21.OOO feet long, every foot of 1t through solid
rock 1t will convey the water supply from the
present distributing reservoir TO thenew one,
which Is to be large enough to supply all the de-
mands OF the national capital for many years to
come After surveys and estimates it was de-
cided to cut the waterway through the rock as
the best and most economical plan. In this way
the costly expenditure for right of way that
would be necessary for surface aqueduct is
avoided, and the tunnel, once completed, will
ioot IOtCNcI WltuOut any uccu Oh REPAIRS.
THE WORKING SHAFTS.
The contractors, Messrs Beckwith & Quack-
| enbush, have sunk five working shafts on the
line of the tunnel. The first is just across the
road from the lower end Of the distributing
| reservoir, and is called reservoir SHAFT The
next is in the valley below and is called Foundry
branch shaft, the next is the Rock Creek shaft
on the eastern bank of Rock Creek, where the
corner Of Oak Hill Cemetery extends down to
that stream. The next is at the head Of Cham
plain avenue and is called after that avenue,
and the last Is called Howard University shaft
because located near the University. Work in
the tunnel has been progressing for some weeks
in Foundry branch and Rock Creek shafts. In
the latter over 600 feet of tunnel has been cut
out each way-east and west. The University
shaft has been sunk to depth of $50 teet and
them the workmen are just ready to turn the
| headings of the tunnel That is, the
shafts have reached the level desired
Tor the bottom of the tunnel. and now the work
of boring through the rock Ia to begin. In each
| shaft the boring and blasting is pushed both
ways simultaneously. The reservoir shaft is
| over sixty feet deep. and the work of tunneling
will begin there soon. Fourteen men are work.
Ing there. The Foundry branch shaft was COM
pleted at depth Of ffty-sx feet and the tunnel
has been pierced several hundred feet each way
A force of forty-twO workmen is employed at
this shaft. The Rock Creek shaft ia the same
depth as that at Foundry branch-ffty-six feet.
Forty-fve men are employed at this shaft. At
ployed, and at the University shaft the force
consists Of thirty-six. The work is pushed for
ward night and day.
THE COMPRESSED AIR WORKS OX ROCK CREEK.
Compressed air has been adopted by the con-
tractors for the tunnel. Messrs. Beckwith &
Quackenbush. as a motive power, not only for
the drills to be used, but also for all hoistine,
pumping and ventiating purposes The con-
tract requires four drills In heading, or twenty
eight drills In all. The power required to run
this combined plant was necessarily great, and
formed serious item in the preliminary work
The well known machinery of the Ingersoll Rock
Drill Company having been selected by the con-
tractors as best adapted to the work in hand,
the first point to be settled was whether each
shaft should be fitted out with separate plant
or central station provided to supply the whole
four miles Of work. This subject was carefully
considered by Mr.. Pierce, the vice president OF
the Ingersoll company, and the contractors and
their consulting engineer. The result of their
deliberations was that the hauling of some 500
tons OF coal per month over the steep roads Of
the region covered, and the amount of skilled
labor required by divided plant, were found to
outweigh, in cost, the necessary pipe line of a
central plan, and the latter was adopted as the
most economical. The supply of fuel being
leading consideration, the central station was
located near the mouth Of Rock creek and d.
rectly upon the Chesapeake and Ohio canal,
where coal could be delivered at minimum
cost.
SUBSTANTIAL BUILDING
was erected, and. within it the machinery for
COMPRISING air is worked DAY and night. A
STAR reporter was shown through the building
by Superintendent j. d. Fallon
The power Is furnished by six tubular
1O0-horse power boilers, each CO inches In diam
eter and IA feet long These boilers are ar
ranged In ono battery. A 4-inch steam pipe
starting from nozzle In the front of each
boiler, each provided with a throttle valve, ETC.,
mon steam-drum. This arrangement makes it
possible to cut OF any one or more of the boilers
at will. Four Ingersoll ''straight-line" COM
pressors. OF $50 horse power each, compress the
air. These machines are Of the latest construc-
ton as regards design, economy of steam used,
and convenience of operation; they have A-inch
cylinders and 3O-inch stroke During the COM
pressing process. the air Is kept cool by spray
OF water Injected into the air-cylinder by small
pump. and Is discharged In this condition into
pressors by 12-inch pipe, which enters at the
top OF receiver No. Cthe central station), and
descends inside to within short distance of the
bottom of the tank; as there Is about two feet
OF water in each tank, the air Is discharged be-
meath the surface, and must rise through this
water before 1t can pass over, through another
l2-inch pipe, to receiver No. 3, alongside of No.
1. 1t there again discharges under water as be-
fore, and finally, from the top Of the second re-
ceiver, passes into the general supply main.
This rather paradoxical method of passing
compressed air through water. to dryjt, expe-
rience teaches is the most practical way of de-
priving it OF the moisture that would otherwise
give trouble by freezing in the exhaust ports Of
the machines using it.
CARRYING CONDENSED AIR TEN MILES THROUGH
PIPES.
To convey this compressed air to the working
faces OF the tunnel, a pipe line five miles long
over ground is required; and by the time the
tunnel Is completed. ten miles OF pipe will be in
use; this will be the greatest distance COLE
pressed air has ever been carried in this coun-
try. The dir leaves the second receiver at the
central station by 12-inch cast-irOn pipe. which
Is laid along Rock Creek to Gay street; thence
through North and Mill Streets to the east bank
Of Rock Creek, and there terminates in boiler
iron equazing tapk, four feet long and twenty
inches In diameter, From this tank the COM
pressed air is carried east and west by two ten
inch pipes, the first running eastward to the
Champlain-avenue shaft, from whence sx-inch
pipe carries compressed air to the shaft at the
new reservoir, the second running to the shaft
at Rock Creek dam, and from there the COM
pressed air is further conveyed in a siX-inch pipe
up Boise lane to Road street, along Road street
to Fayette street. along that street to the new
road and thence to the shafts at Foundry branch
and the distributing reservoir.
The plant operated by this compressed air