New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1875-06-14
THE CIVIL ENGINEERS.
CONVENTION AT PITTSBURGH.


1IoSs FOR RAPID TRANSIT RAILROAD CHEAP
RAILWAY rREIGHTs-GoOD EFFECTS OF THE
GRANGER MOVEMENT
.FRox STAFF c0RREsPoSDgsr or Tilr rRiDuNE.l
PrrrSsuRGu, June 10.-With the greatest
unsunty feeling. there is wide ground for difference
u opinion among civil engineers on what is known as the
Bridge Question II Is cugrowth of the bridge acc-
dents ~ iast year. which committee OF bridge builders
belonging TO the society vi Civil Engineers took into
sider,iion They brought in majority and three minog-
fly rsloris and euce the bridge business has been
vcxcd question. The disagreement is TO the means OF
preventing such accidents The majority Of the Commit
tee favor the adoption OF standard that all bridges
shcud he eui 10 carry not less than certain number Of
pounds per square foot; the number being fixed
Ia tables with reference Ia span and the
uses 10 which different classes OF bridges
are subjected These fables woud require bridges VIII Oh
arc within the limits Of safety Brt Tho
opponents of ,his proposition THAT no account is
made by u o. the difference in iron or other materials II
the best iron for instance is by this restriction 10 bo
used m tao abundance with the worst there Is no
object 4, he gained by using the hest AID the result
would that the rule would be ignored or inferior
materials would he everywhere used. Gen Ellis dis
cssng subject sad that the Committee seemed 70 be
unsns to the load which ougt % be used 70 test
a rairoaA bridge: two heavy locomotives aud
train az ears loaded 70 The maximum. But while Cen
Ellis thinks that this weight OF engines alone Is "a
strain Of 1000 pounds per square foot, there were
Others thought the actual pressure at ono point
on the h8igc would exceed 5000 or perhaps 5000,
pounds Hc would solve The problem Ivy making the
standard not given number OF pounds to the square
.inoi but percentage of the breaking weight OF the
metal used In construction Bat then II did not
sce advisable provide against the carriage Of heavier
locomotives than used by the specific railroad
HEAVY LOADS BY Raj.
There WAS indeed the possibility of having TO carry
locomotive seut freight freight ear but not prob
A fn.f nj
heavy loads he mentioned the transportation of stone
for q cemetery in Connecticut that weighed 40 tons;
but said he, "the bridge tat went over would have
stoed anything. and IL was not injured Mr.. Mctcahc
ted OF hs experience in sending on the great guns OF
the Pittsburgh FoundIy. lie had often becu compelled TO
Wal, for wees till bridges could he strengthened TO sup
port those iron monsters. and sometimes tho gun
founders had TO the bridges OF the railroad com
rancs against damage. Mr.. Shedd related some OF the
similar difficulties In transporting the castings for the
Providence waer-works. In instance il was found
necessary 70 cut a large casting IN two.
Mr. Hcrschel advocated the plan OF suhjcctng the iron
used fcr bridges 60 specific tests The fact that such
tests would applied would contractors To FUR
nish good iron Mr. Clarke engineer of the PhenNvilie
Bridge said that Western people were urgent that n
efander strength for bridges should he fixed Bnt II
the State was TO select experts to decide upon bridges
The WI business would become too soon mere Po'
zeal placer. There discussion over the mathematics
of one 81 the reports and they explained 10y MI
Macdonald Bat he thought that " the strength OF INC
iron used WAS be taken into account the limit OF It's
elasticity was far important factor than It's break
ing strene i he named instance where the former
was only cne-half the latter
To-day Mr. Macdonald urged the adoption OF the ma
,criiy report Oh preventing bridge accidents lie would
somewhat modify IT, and he proposed that committee
of three appointed 10 report whether legislation on
the subject should be recommended. Mr. Briggs speak
ing On the didiculiy of Knowing what strain bridge
, a.. ;.rfa nead That had
nous weight of and ice deposited on it. nAniicsy
the standard Of safety Ia that differed from what
weud DC n q southern State He saw no provision
for Of the commences, forms OF bridge aecdeht'
where train thrown of the track and tears to pieces
vital portions OF the bridge structure, that the whole
mass ia pcc yitated into the river below He casually
mentioned his own disbelief IN the notion that
frn weakened 10y cod lie had kept foT two years rec
ORD of brekagos OF rails and there Was no difference Tor
Sudden changes temperature, and no increase on days
OF excessive cold. Good iron certainly Was not thus
Affected but there less taken 81 the road in The
depth ~ winter
Mr. Ls spoke of the difference Of iron used In various
localities The nglish factor OF safety III bridges was
oseihrd: only onefifth. Mr.. Herschel SAID that
Frtnee. Prussia, England, and some ninor European
had adopted laws respecting bridges defining the
strain they must csr 10 the square ineh; slhce 'hcse
lsws wen, into bridge accidents lad happened
fu those States Ths public demand OF the engineers OF
this country a similar protection
The discussion has probably gained friends Tor TIE
Cnsitees report, but there yet remains considerable
number OF engineers who are not convinced OF It's
wisdom.
RAILROAD sIGNAIs-TuE EoRwAIK DISASTER.
The topic OF railroad signals being bgought up some
what paintive reply elected from Mr. Fisher VINO
had found that railroad companies treated VIII ID
xuat.te al suggestions the subject Jhey had tlcii
own ~ stcIns, and regarded innovations with dsiraSt
Moreover just about the time when The Committee Oh
"A ID their gathering IN
formation the Society itself had given them the cold
shoulder. Yet scarcely week passes without an
sccdeut that might have been avoided by an eihcicnt
system of railway signals Tho presiding MI siinn
gave the baul sympathy 10 Mr. Fisher and related as
notable instance OF the danger from bad system OF
ra.ysy signals the facts In the NOrwak Bridge dsds
ter IL was tile result of mistake OH the part OF The
brakeen to what meant by the engineers signal
He swoe th: he blow blasts OF his whistle, mean
ing Down brakes" The brakeman sw0re there was DhS
one wssle which conveyed no such order Probably the
eDgneeT did sound the whistle twice, hut in haste ana
M he lett too short an interval between aud
the sound oOacsoed they reached the brake
mans But the was III the 81 stem Of signals
ros grug two whistles for danger and one for safety
To slre gick efficient work, those signals should have
meani exactly the reverse
RAPID TRANSIT IN CITIES.
Mr. Richard II. Buel of NewYork, not being able TO
c,s with the Convention sent TO the Secretary paper
which read, containing severe criticism upon the
report Of the Committee Rapid Transit. TO this Sr.
Colngwaod replied that the Committee had not found
any practicable scheme Of rapid transit on paving
basis hut they did propose select any scheme
rs The best since some the plans from members
OF the Society Ills morning Mr. VIM IL seaIes OF New
York rosuming the debate this subject, said that
an ordinary railroad is built only TO accom-
push long journey in short time;
rapid transit requires high speed with stops at
frequent intervals Great loss Of power is incident to
ffa
loss ~ power Is disprcportoDatcly augmented In
the case supposed the velocity between the