The Elk County advocate. [volume] (Ridgway, Pa.) 1868-1883, 1877-02-01
IRON IN RAILWAY STRUCTURES.
Deep Rooted Popular Belief yh,,, ,.,.,
will S',,d

-s"NNs
Dur.riag the nrst few DAYS after the
uIsaster to the Ashtabula bridge, there
appeared frequent and very positive
statements in many newspapers to the
effect that extfeme cold always made iron
brittle. On the other hand a few equal
ly positive statements we're made, based
upon certain European experiments,
affirming TINT the strength of wrought
iron was not in the least reduced by
cold. The Tribune melt 'oned at the time
the results of certain experiments in this
country. From these it seems evident
that bad iron may become brittle in cold
weather. while there is little if any dan
ger of the kind with the best of iron.
The testimony thus far obtained at the
inquest, and before the Legislative COM
mittee, furnishes already n variety of ex-
plantations respecting the disaster. There
is some evidence that part of the
wrecked train was off the track; some
evidence that the plan of the bridge was
of doubtful merit, it being an attempt
to substitute iron for wood in n method
of construction for which wood was
better suited some evidence that the
bridge, after the metal was furnished,
was put in place or erected" by an
ignorant and incompetent man; and
some evidence that after the bridge was
built and tested, in was allowed to fall to
pieces through the culpable neglect of
the railroad company. Any one or all
of these circumstances, if proved, may
afford reason enough for the ruin of the
bridge, without any question as to the
iron which it was made of but the fact
will remain that large proportion of
the public puts only doubling faith i'll
iron bridges, and really thinks them
dangerous when they have stood many
years, and especially during frosty
weather.
1t rarely happens, says the New York
r Tribune, that a deep rooted popular be-
lief is wholly mistaken. 1t is more than
likely to be founded in half truth.
When farmers hang their new scythes
outside the barn in order that the steel
may rust and thereby improve its tenn
per when for similar reason some
worllmen bury their tools in the earth
while not i'll use when blacksmith
picks the oldest iron i'll his shop for the
choicest work, there is certainly evil
dence, so far as popular belief can be
alleged as testimony, that age and ex-
posure improve the metal. Men who
have studied the subject give reason
for the improvement of iron or steel i'll
such instances they say that the i'm
purities of the metal are brought to the
surface and thrown off by slow rusting.
Prof. Thurston has cited the instance of
the rails on the Camden and Amboy
/ road, laid down in 1889. They were then
! brittle and of poor quality. Taken up
i'll recent years they We're found to be
excellent stuff, and when sent to the
rolling mills furnished barirOn of unusual
excellence. This and similar in stances
seem to set at naught the theory that
the vibration OF passing trains causes iron
after a while to crystalline. Robert
Stephenson and john A. Roebling dis
tinctly recorded their disbelief in the
crystallization theory. William Fair
BARN, on the other hand yielded
modified assent to it after opposing it.
But the report of the Hoosac tunnel
commissioners presented n fact that could
not be set aside. The rock drilling
engines used in that work gradually be-
gan to fail in strength. After the
metals used in those machines had given
millions upon millions of blows, they
began to granulate, and lost cohesive
ness. In certain French experiments
which combined torsion with shock, it
was found that 129, 900 blows had no
perceptible effect upon Il new axle ;
33S, 900 blows caused change in tex
ture that was seen by the naked eye !;
after 7S, 100000 shocks the metal, when
broken, was found to be scaly within.
like pewter. A testing machine long
used in the navy yard at Washington,
and fitted to bear a strain of 300 tons,
broke down mt last with only one hun
dred tons. Its fracture showed we'll de-
fined crystals.
Against such facts are to be put proofs
positive that iron tested by Prof. Thurs
ton and by Commander Bear lslee i'll
widely differing experiments gained
strength and absolutely stiffened under
strain. In one of the Bear1slee expert
ments iron that broke under strain of
$1,000 pounds was so improved by its
treatment that it sustained 200 pounds
without fracture on the following day.
Equally conflicting is the evidence
about the effect OF cold. The late Mr..
Rocbliug kept samples of iron in snow
and ice for heightened period, and
tested them while cold both by weights
and blows without finding the least
deterioration of strength. The railroad
commissioners of Massachusetts in their
report for 1874 scout the idea that cold
makes iron or steel brittle, and declare
that it is not the rule chat the most
breakages occur on the coolest days.
German railway statistics for 1870 give,
however, two-tifths more aXles broken in
the cold than in the warm half of the
year. In Woods treatise on the re-
sistance OF metals, where most of the
foregoing facts are stated, there are men
toned several curious instances of the
sudden breakage of iron, and an abstract
is given of the experiments Of Mr.. Sand
berg, of London, which showed that
ordinary iron rails had at ten deg. Fab.
onlya third or fourth Of the strength
they possessed at eighty.four deg. We
have cited experiments which seem at
first sight squarely contradictory, and it
must be admitted that much yet remains
to be learned before either view can be
held with certainty. Out OF the mass of
evidence one fact alone remains unques-
tionable that the best of iron and steel
is the least likely to give way under
strains, shocks or changes of temperature.