Evening public ledger. [volume] (Philadelphia [Pa.]) 1914-1942, 1915-08-20
FNGINEERS FACE
BIG PROBLEMS IN
SUBWAY DIGGING
r.sk the Most Formidable
q the Kind Ever I'm
dertaken Here
,aNY HUGE OBSTACLES
Must Be Accomplished With
out Interruption of
Traffic

a.. arst ground is broken for the
Nhsn ,-aot subway construction beneath
fIoso. an september 13 the greatest
cry d. .,,tneering work ever under
ftl, q r,hiia delphia will have been In
nktn ~ The cost of the tunnel be-
ug.n' c,sv Hall will be N,70O.OOO-not
ralh ,roynt for municipal contracts-but
~. ,he standpoint of obstacles TO De
nan n1..o,,e and engineering problems 10 be
wa the project will be without par
~, n any underground construction
s.. ~ ever undertaken here.
greatest problems which confront
=. ~ .,sineers are the underpinning and
" u.osnr ND OF the entire west side OF the
~ Hall together with almost mar OF
cq nth side and a short length of the
pt s,de: tunnellng under the present
'.r.t street subway tracks on both sides
~, Hail without disturbing the traf-
W. o.a'.ssdsrninning the corner of the West
~ Trnst building and bulkheading the
~ foundations of the. Broad street
x..,cn and the Lincoln Building.
Z .aaitIon to piercing and propping up
~ ~ - armous foundation walls of the city
W, the engineers will encounter an IN
ns~ A.,s network Of pipes, large and small,
s',sS,ng water mains, high pressure hre
.,ns telephone and telegraph conduits
~ drainage pipes. Three of the large
80 ~ mains are 4S inches each in
tsmeter.
IA to the difficulties of the work,
II. snsciflcations for the contract re-
,a,re that the present subway and sur
~. traffic and vehicle and pedestrian
.se,c must not be disturbed. When the
s-.ss having is to be broken, this work
s.sst no done after z o'clock at night, and
= -.ooden deck of sufficient strength to
.nnnort the street traffic must be laid
~ fhe openings before o'clock In the
..rnlng. In this way the great work Will
y carried on without disturbing the
,r.,Ic IN the heart OF the city's busiest
district.
ma ,pnnel itself will be 200 feet in
a.,gth. II will extend from the north
III of the present Market street sub
N, structure in Filbert street. at the
.srthwest corner of the City Hall, to the
,outh wall OF the Market street subway
4. gouth Penn square, midway between
n, southwest and the southeast corners
n the City Hall.
rhe ANTIQUITIES of the work, perhaps,
nav ne better realized when it Is under
,told that the tunnel, 700 feet long, will
rcsi yl.7OOeOO. This means 2429.57 a foot,
a. s2oess ar inch. Or to raise TO larger
psoportions it would mean cost OF $n,-
paHsss per mile. At the same rate the
,niIre Broad street tube would cost APP
proaimately s12OOOO,0oO, instead Of sS2,'
fkoo0 as estimated by Director Taylor
Between now and September 10 Di-
rector Taylor and the engineers of the
CITY Transit Department will confer with
the contractors and go over their plans
for prosecuting the work. Drafts of the
derricks to be used and all. other large
implements must be shown to the transit
o15eials and approved by them. s
Before any digging can De undertaken
ach OF the storerooms under the western
va Of City Hall must be emptied. The
work of removing the contents of these
rooms will be under the direction of the
Bureau of City Property. This work will
hgun at once in order that there
nay be no obstacles remaining at the
iofmsi opening of the real digging OF
4piember 13.