The true northerner. [volume] (Paw Paw, Mich.) 1855-1920, 1871-05-12
TUNNELING THE CHICAGO RIVER.
The La Sale Street Tunnel-Its Cost and
Statistics-An Interesting Account Of the
FROM Che Ohicago Republlean

How much clay is there between the
top of the tunnel and the bottom of
the river ?" asked the reporter of his
guide.
Time, Saturday afternoon. Scene,
under the bed of the Chicago river,
main branch, in the middle of the La
Sale street tunnel. About us stalwart,
red-shirted men, who, by Pickering can
delight, were dipping bucketsful of
Shiny sediment from the sewer beneath
the tunnel. Under foot the new Nicol.
son pavement, sticky, gritty, odorous of
tar and fresh pine.
How much clay is there between
?' said the guide, repeating the
query. There's none at all, barring
the sediment of the river. It's tagged
| as clean as stone sidewalk"
One always thinks in a tunnel, as one
always thinks on loft railway viaduct,
"What if an accident were to occur -
What if the masonry should give way
beneath the superintendent weight of
waters. No chance to flee only one
thunder, one rush irresistible, a few
bubbles in the water, and all would be
over.
4No lCdi Wis, HOWcNcI. OIlS WOulu
hardly know that he was not in the
basement of an uptown house, so dry
and airy is it. Not drop of moisture
on the walls or arches, not crack in
the cement, nor fault in the masonry.
Locking up at the arches, with their
! ten courses of bricks, their solid cement
and water proof asphalt, and remember
ing how much money has been expend-
ed, and how much engineering skill
called into req .lsi,ion Oh this work, the
timidest female mind is treasured, and
Lady Clare considers it nice, dear old
tunnel, when, with boots and bit be-
mired and skirts u triie dusty, she
emerges into daylight, dust and clatter
on the North Side, on Michigan street.
Now for the statistics, without which
the ARREST report is but as sounding
brass and tinkling cymbal. The works
at the La Sale street tunnel were begun
OH the 10th Of January, 1870. The con-
tractors, Messrs. Morse, Chambers &
Macbean, engaged to complete the
work for $427 900, but alterations and
additions will swell the cost TO a small
trifle beyond 100000. The tunnel will
probably be opened to the public on the
4th of July. 1t could be opened to foot
passengers within fortnight or three
weeks, but delay is necessitated by
the taking up Of the pavement in order
to put in a three-feet water-pipe. At
present, the approach on the North
Side is graded paved and completed.
! There is one alteration to be made in
the ventilating shaft, which is to be
| .la, int chof no
center section is in complete order, the
laying OF the Nicolson pavement having
been finished. The approach from Ran
dolph street is not yet completed, but
masons are busily at work laying stone.
! The excavation was finished on Thurs
1 day night, and the roofiingin is rapidly
| being proceeded with. Messrs Morse,
I Chambers & Macbean have employed
from POO up to $50 men on the tunnel,
working day and night, and no acct
dent has occurred to delay them The
soil has been favorable, and the work
has advantages over that on the Wash
ington street tunnel. inasmuch as it is
dryer, and the gradients are easier
the rise on Washington street being one
foot in sixteen; that on La Sale street,
one in twenty.
Figuratively speaking, the tunnel is
in the center of La Sale street. Its
southern approach commences forty
feet north of Randolph street; the north
ern approach terminates at the south
line of Michigan street. The bottom of
the tunnel, in the center of the river,
is thirty-fve feet below low water.
Tha Il =
bed, is 300 feet long, and consists of
three distinct ways. The eastern pas
sage is twelve feet high and ten feet
wide this is for foot passengers. The
other passages are each eleven feet wide,
divided from each other by walls TWEEN
| ty.eight inches thick. The abutments
are four feet thick on the east side, and
| five feet thick on the west. The thick
ness Of the upper arch is &c ID inches
Over all, flag course 10 inches thick is
laid from one end of the tunnel to the
other.
So much for the central section. The
side sections commence at q distance of
$50 feet from the center line Of the
river. Here the tunnel changes to a
single opening, "A l.3 feet wide, decreas-
ing to 10 l-2 feet in a distance of 40 feet.
The height-which in all cases is from
the top of the invert-is 81 feet to the
bottom of the top arch. The arch is 81
inches thick at the sides, and 81 ID at
the top.
After this section of 40 feet has been
passed, the heig of the arch is 10 l.2
feet, its thickness at the side 20 l-2
inches, and % inches at the top. This
third section is 423 feet long on the
south side, and 33S feet long on the
north side. Then the arching termin-
ates, and covering of iron Orders and
brick arching runs for GO feet toward
Randolph street, and 1875 toward Michi-
gan street. Here begin the approaches,
$50 feet to Randolph street, 2l5 feet to
Michigan street, the walls at the sides
diminishing from 81 feet in height,
where they join the passage-way, to 5 l.2
feet at the extremity The total length
of the tunnel is thus 1887 feet, includ.
ing the approaches. The Washington
street tunnel is only | SOB feet in length.
The tunnel is drained by means of
well at its lowest part, ID feet deep and
feet in diameter. This we'll is con.
/ raotaI bv a five faot hr,oly ca,yor ,v;th n