The sun., 1901-03-17
0rEER TUNNELLING THIS.
,ynE CAVERNs FOR THE SUBWAY UN-
DER WASHINGTON HEIGHTS.

no~n In the bowels OF the earth under
...,h Washington Heights men are now en-
..osd In tunnelling operations In connection
r,,h IN. construction OF the Rapid Transit
abroad, which will rank when completed
.r,ons the II eat tunnelling feats OF the world.
Wor, Of a decidedly interesting character
/, belns done in many parts Of the city on the
.,busv. but at no other section OF tn route
A N. operations have the same interest
,,r .nsneers as those in connection with the
obstruction OF sections Is and i4-from is3d
street 10 Fort George.
Tbs character Of the operations there 10 due
,o the peculiar nature Of the rock that has
h.sn encountered. The cleavage OF this rock
from the surface down Is such that IL has not
,.opir.d the use Of timbers for snoring pur-
ro.s. and has permitted the excavation OF two
sham bsrs at the places where the stations are
~ b. located which are probably without
.,n.l, anywhere In the world These cham
hsr. have been hewn out OF the solid rock
a, a depth Of over a hundred feet from the
.urface and In them men can work and
.vsn blast with perfect safety despite the
ian. and tons OF rock that lie above them,
and which are absolutely unsupported.
The natural obstacle which nature seemed
=, sr.t 20 impose 10 the construction Of the
,nnnel az this point and which the engineers
h.v. regarded as by far the most difY1oult
ha,no, after all been so great as was ex peoted
bsoause Of the unusual cleavage Of tho rock
IN consequence OF which tn e work has been
sr.stly accelerated. Contractor McCabe has
m. contract for sections i3 and II. and IL was
a, on. Of them that work was formally COM
mepc.d last July when Corporation Counsel
Whsl.n with a silver pick turned the first
.arth, or rather rocks on the subway system.
r,sSd street there is now a section Of 100 feet
that Is only waiting for the tracks to make it
look like the pictures that are SO often seen
NJ the tunnel when completed. This section
vas finished last December and therefore
has the distinction Of being the first mad 9
ready for the running Of trains
II sat l33d street that the trains will dive
into the earth again after crossing the viaduct
that Is 70 be built across Manhattan Valley.
and from there the ground steadily rises
with a few dips here and there until Fort
G.orge il reached. When the plans for the
urnsl we're made Il was seen that this would
h. probably the most difficult portion of the
work for the reason that the hill is OF solid
rock recessitating tunneling on scale at
,smptel in this country only in the construc-
lion Of 'he famous Hoosac tunnel
A. the highest point OF the hill al igOth
,,reef the height above tide water l. 225 feet
and the tunnel will be about l50 feet below
lie surface This depth and the rocky char
Aalar ID, The Nil made II necessary 10 have
a. fsO opening shafts as possible, and Con-
tractor NoCale determined to construct
'hrn At only Two places one at l6sth street
and the other Ht lSlst street, at both oi which
call l.l tuft hn
work of dlEunE these shafts commenced
a,r uA and the required depth was not
reached ur'l December At the same time
lnupillug Wa commenced where the open
vorh ,-usc, ~ lj7th street and whore the
hid begIn- to attain such height a. 10 make
aru.al wnneug necessary. The tunnel
nero has now been extended in the direction
@, Fort Gr1rgc about 900 feet from the end
inrar... character. because even here the
rock shows the same cleavage that II does
iaffle~ ON. l. not as Interesting ~ that AZ the
40 points whore the shafts are. as IL shown
h, tho different conditions under which the
work ~ those places i done.
A. t'th street the chamber. which will in
nr9r boz transformed into station, is at
hg.'nn II lus feet, and AZ lSlst 'et at depth
y lli feet 70 get down to tuesa. shafts Is
los 81 feet W,r' sunk IL took from July to
h"cemb'r &" cut these 'ugn the solid
rck b,'' So only limitc0 numh'r { r'"n
.u.h NJ iu them. Mh"u the rpuu'r ii
dspth Wa reached the cons Faction Of me
,aambar t,t- commenced u had been
.Yppo Scd that great deal Of snoring would
ba necessary, as IN ul mining Operations,
Tho engineers were therefore very much
sIrprIsad when after the first few feet of
pricIas~ had been made away from the foot
dcach shaft the rock retained lts compact
nes. and showed no signs of needing support
q ,cnp pieces Of il falling from the roof and
.lda- v the work proceeded the rock was
rarouly examined 10 determine If the in
ere cd strain made any difference. but 1t did
,, tIt.ah h,,T tttarh "a lynt n
M more wonderful With every foot OF prog
lss, H 1de
wa. permitted to SEQ the other day after
having obtained a pass from the contractors
10 ~ down the shafts in the cage II was as
7 oro had been suddenly transported 10 the
mining regions Of P"nnsylvanla IN almost
conuleto darkness men were working with
great impressed air drills. aud cars were
helnc loaded and unloaded The chambers
rm Uutrh and south aud are 20 feet high and
p feet wide Where they open into the SHAFT
hoy are - feet wide From heading to
heId.'g a. he ends are called where the
work les in progress. the distance IN the cham
her ~ IGs,h street was last week about 1870
'ae' and = 'sI~t street about isr feet These
chamber, are sltiiCien'lv large to hold tracks
I'D .tallon. fOo,and Il will be up the same
hat 'u11 ar" now IN use that the .passcr-
seg, H.l b" carried In elevate ors when the
4. 'ha-" fwo great rooms Of rock are at
rra.u. there is l!ttlp TO suggest what they
~" '"rdod for They seem irstcad like
gregf natural cavPrnS accidentally revealed
b, no shafts A. they Ieretrated ha earth.
frtn'h" men work IN Sh'tts day and N ght.
At hat remains I o b" done 10 make the cham
hor. conform 20 the shape required for the
stations l' 20 extend them a. each end until
'o. tGe 22D feet long The work OF tun-
re.Hry done with compressed air drills
sld d'uau 10 Blasting i only done az the
chang" - shifts. for every one has to be at
'as surface when one Is set ofr, as the dyns-
W'c 'l> ha chambers with SufOcatiug
sn.,n
fhell1st,ngis il done In what is called benches
or tors. 'Urea benches making up he height
and ndn = the chamber. Each shift drills
hr..'. 80 at the end q iweniy-four hours
no 'Hr'o, has been extended about siX feet
" eo f. end he tunnel narrows when the
70 " ."N viii proceed much faster. After a
0.It p ., 'u" duty - the foreman II th" nryt
''' p" examine th" wall, opd roof of the
..4'. aur 80 500 how they survived he shock.
N.ul"' .- mi. rock. however, that even after
= ..H-' 'la' has dl~lodged SiA cubic wares
-" 'N"r" has not been found aS much a.
'..H watch would port"nd danger II
I"Nn nG these depths tho men engaged
' .r ~ and cartiug the stone dislOdged
.' '.n H.t-'- lu IN" shaft M which the cars
AT" ''"i work in semi arkne~- for all the
- ''.I' they lave comes from a lew Ra-o-
o." .S.'s placed I'm The immediate vicinity
OF '.. H..I- fl-cwhpre il IL almost ~ dark
H ng p" he visitor from the upyer world
.'. . he's long time for the eyes 10 get
"'.i.. r.'i & ii efficiently t. see the WALL
.l' r.' of tu" great cavern From the
e'''.. = 'N" hig room the little hiCkeriug
'.,' -uow whore the mon ar" working
zee HVay The noise made by the drills
',, '.. nlrp" with an lndesCribable din.
N... o N'N reporter Went down into the
s.''' ~ iNth street the other duv the men
".. ,'Sng shifts. Quite "A few are veteran
me, '-Hn Pennsylvania. and almost all
a'' Bal previous experience in tunnellug
N'. CONTRACTOR McIHhc About thirty men
.t..r n, shift and when tho first nf them