The Vancouver independent. (Vancouver, W.T. [Wash.]) 1875-1910, 1877-03-16
Iron in Railway Structures.

ments in many newspapers to the effect
that extreme cold always made iron brit
tie. On the other hand, few equally
positive statements were made, based
upon certain European experiments af
firming that the strength of wrought
iron was not in the least reduced by cold.
The Tribune mentioned 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 danger
of the kind with the best of iron. The
testimony thus far obtained at the inquest
and before the Legislative Committee,
furnishes already variety of explana-
lions respecting the disaster. There is
some evidence that a part of the wrecked
train was off the track; some evidence
that the plan of the bridge was of doubt
full merit, it being an attempt to substi-
tute iron for wood in method of con-
.struction for which wood would be better
suited; some evidence that the bridge,
after the metal was furnished, was put in
place or erected" by an ignorant and in
competent man; and some evidence that
after the bridge was built and tested, it
was allowed to fall to pieces through the
culpable neglect of the railroad company.
Any one or all 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 proper
ton of the public puts only doubling
faith in iron bridges, and really thinks
them dangerous when they have stood
many years, and especially during frosty
weather.
1t rarely happens that a deep-rooted
popular belief 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
temper; when for similar reason some
workmen bury their tools in the earth
while not in use; when blacksmith
picks the Oldest iron in his shop for the
choicest work, there is certainly evidence,
so far as popular belief can be alleged as
testimony, that age and exposure i'm
prove the metal. Men who have studied
the subject give reason for the improve
ment of iron or steel in such instances;
they say that the impurities of the metal
are brought to the surface and thrown off
by slow rusting. Prof. Thurston has
cited the instance of tie rails on the Cam
den and Amboy road, laid down in 1882.
They were then brittle and of poor quality.
Taken up in recent years they were found
to be excellent stuff, and when sent to
the rolling mills furnished bar iron
of unusual excellence. This and SINH
lar instances seem to set at naught
the theory that the vibration of pas
sing trains causes iron after while
to crystallize. Robert Stephenson
and John A. Roebling distinctly recorded
their disbelief in the capitalization
theory. William Fairbairn, on the other
hand, yielded modified assent to it after
opposing it. But the report of the HoOs-
&C Tunnel Commissioners presented a
fact that could not be set aside. The
rock-drilling engines used in that work
gradually began to fail in strength. AT
ter the metals used in those machines
had given millions upon millions of
blows, they began to granulate, and
lose cohesiveness. In certain French
experiments which combined torsion
with shock, it was found that 1884,
900 blows had no perceptible effect
upon new axle; $685. 900 blows caused
change in texture that was seen by the
naked eye; after 7S,000,0OO 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
800 tons, broke down at last with only
100 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 aud by Commander Beardslee in
widely differing experiments gained
strength and absolutely stiffened under
strain. In one of the Beardslee expert
ments iron that broke under strain of
$4,000 pounds was so improved by its
treatment that il sustained 5000 with
out fracture on the following day
Equally conflicting is the evidence about
the effect of cold. The late Mr.. Roebling
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 that the
most breakages occur on the coolest
days. German railway statistics for 1870
give, however, two-ffths more axles brok-
en- 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,
.ato of