New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1903-12-12
HARLEM RIVER TUNNEL.
Ton To Be BuiIt IN -4ir and LopereG
Into Ditch.

70 the Editor OF The Tribune
Sir. For she construction OF re ea7' 81 % 80
liver portion OF tire Harlem tE4FeF l~iliei III 's
,,-v fo- rbe Rarid Transit Railroad an prepared
- -. 49,, -~ot,.,5 have adopted therefor and
= - Zinc OFT wiz be great Improvements
=, ~ -syel method under which successfully
-,s-,,,rrss the west half OF TIE river portion OF
sale tunnel
F7-.eev seated. the first method was TO dTedge a
- --,~s the river bottom 10 within few
- -, ful depth o. excavation required 10
- -, -r-1eI II KRIS channel. foundation piles
- - n specially prepared heavy timber
-te.-ts,r along each side and across the ends.
- +-trsn ard GU or TO a true plane about
- SO. seet below -he surface OF the water.
-. sbssrhing forming the sides and ends OF a
.--ss,e working cha 1abe--
- 49, roof OF this chamber platform OF timber
- inches iu thickness and extending the fun
,fsrb and length ot The tunnel section was built
and sunk and rested on the cat-on sheathing. which
formed the sides and ENDS as above described
simultaneously with pumping The water from
,.r5sr tins roof compressed air was forced into the
s---rhs- under pressure corresponding TO the
pressure % The water above the roof Inside this
cha-rber the west half 81 the tunnel built and
then The timber roof was removed
TIE new method for the east half OF the river
briefly stated Will be 20 prepare the sides of the
pneumatic working chamber as above described bur
me shea1h-rs and piles VIII be c1I Of about twelve
fee1 lower do0a thar was done ia the former case
exactly aa -as sraee OF The spring line Of the
Erch of tle tunnel
TIE JCV haf OF the tunnel wiI be bulk al the
surface poutoons. then launched and hoated Over
the tunnel site and sunk into Its final and true
position. the outward fanses of il resting on the
crt-0 sleathirg above described then the top half
Of the tunnel VIII be used 10 form the roof Of The
pneumatic working chamber
u this chamber the foundation and t,r-o-, half
a the tunnel STiII be constructed with the use Of
compressed air thus dispensing with the timber
roof used in the first method and greatly de-
c-easi1s the cost OF the construction OF the tunnel
IL many ways
THIS method is bringing the construction of sub
aqueous tunnels 10 fire point Il provides for pre-
par.1s q foundation where the material under the
be- o. the river is not sufficient IN itself The
shelthins which forms the sides OF the working
chamber IS driven deep enough 10 penetrate and
oclne the earth material under the tunnel for sew
era feet below sUb-grade- The foundation piles
driven II this confined material compact il.
This method enables a tunnel 10 be constructed
under & navigable river with the minimum depth
q water over Il that the United States government
requires for navigation.
For Illustration. take the tunnel now being con-
structed across the East River from Battery Place
Manhattan 10 JoraIsuon-st. Brooklyn. BY this
method that tunnel may be raised Ihirty-fve feet
higher Than II is now located and srl be below the
United states government dredging line: by thus
raising i- there would DE 51o feet or 81 per cent
O. the grade eliminated.
10 meth cd IS
70 sLnae-eo-5 tunnel work what pneumatic Gals
sol work is 10 deep excavation work, namely, aosO
lutsly safe and sure.
By TINS method the pneumatic working chamber
is built place Immediately encOnpassing the
n n Isl correrlalanceG by the pressure Of COM
pressed air forced within il, consequently IL is
Der under pneumatic ca-ssCn sunk from surface
would have 10 undergo. therefore il is much cheaper
his rnelaod makes possible the construction Of q
tunnel any desired shape or dimension Tunnels
NE ~TyT ~ re red
-39-s 40 s-re~o5rr Gazing 0r7arres vbe-e q
sized whereas with the shield process they are lin
sosbis -racI- funnel car D. bIIiI1 JnSer this
method much less cost than twice the cost Of 4
single track tunnel. four track tunnel much
less than twice The cost OF double track tunnel.
TINS method makes possible the construction Of
runnels with light grades il the sand across such
rivers as the Ohio Missouri and Mississippi. and
provides against their being undermined 4 u1odih-
cation OF This method is provided for cases where
ne river bottom Is rock. 70 bring the roof OF the
tunnel 70 The TOP q The rock II required
~ ms method roadway tunnels with !igat
graoes Ior teams ana loot passengers may he built
across Tie Harlem River At much less cost than
TINS method enables the construction Of a tunnel
Win 2 lEll grade across the Detroit River at
eo-,eIec y ire original attempt 10 build tunnel
The use Of compressed air in driving z tunnel
u air sufficient 10 keep The water from running IN
al the face at The TOD of the shield whereas with
ms method there IS nor any such danger.
this method Is compared with that Of tunnel in
our streets II Is found that as the excavation for
he- IS ~er-s~e5 because the air pressure Within
ne working chamber Offsets the pressure from
n rhe tunnel m the 0ren air al the river as pro
1te-te- 70 the street and place - as must be done
lower half Of The tunnel Is somewhat in favor Of
the land section. but not 10 any great extent extent
a-eE-Yo-k City. Dec. 10 1893.