The Topeka state journal. [volume] (Topeka, Kansas) 1892-1980, 1898-10-27
VAGRANT CURRENTS
Of Electricity Becoming a Menace tc
New York.

New York, Oct PA. A. Knudsen
read q. paper before the last meeting of
the American Institute of Electric engi-
neers on vagrant electric currents and
the vast amount of damage that may
be inflicted by them on all metallic
structures in whole or in part of a sub
terranean character.
Mr.. Knudsen showed a s the results of
exhaustive tests made by him that the
escape of the electrical current from
overhead trolleys excised a damaging
influence on the elevated structures and
the system OF water pipes in the upper
parts of the city.
He also showed that currents escap-
ing from trolley lines in Brooklyn found
their way into all the lower sections of
New York, affecting by electrOlyis not
only the pillars of the elevated roads
but possibly the very anchorage OF the
bridge ITSELF He recommended that leg
islative action be taken to check the
danger, declaring that unless reguia-
tons were adopted the life of public
property would be greatly shortened.
Dealing with the results OF electricity
tic action on the terminal rails of the
trolley system, it was found that a large
amount of metal had been removed by
electrOlysis, the bottoms of the rails
having been cut down to knife edges
for several feet back of the ends. It
was also found that in many instances
the tie rods and cross bars, which keep
the rails in position, had been eaten en-
tirely through.
In describing one of the most remark
able of his discoveries, Mr. Knudsen
said; Coming down the west side of
the city 7 was surprised to encounter a
fun hedged trolley current in the eX-
IRENE lower part of the city. The first
intimatiOn was found at Rector and
Greenwich streets, il becoming more
pronounced in the vicinity of South
Ferry. where, in testing between the
rails of the Metropolitan cable road and
an elevated pillar, variation of one
thfrieths TO eight-thiTtieths volt was
found, the rails positive. and the same
reading between the rails and the water
pipes.
after making further tests the cur
rent was found to come from the Brook
Ign bridge. Having pointed out how an
overhead trolley, using the water pipes
and incidentally the rails as a return
can spread its influence for 20 blocks
north and south, the existence of this
current through the bridge is accounted
for
The very serious question presented
itself, he continued, in what condition
might we expect to find the anchor
bolts and the iron foundations of those
pillars, for previous to any use of cleo
tr1city on the bridge it had been known
that currents were escap ping over that
structure from trolley lines in Brook
lyn and, passing over, would find their
way through the city by underground
pipes, and thence recrOssing the river
arrive back to the power house in Kent
avenue.
In conclusion he said: ct appears to
be the duty Of engineers to exercise ev-
cry precaution against the effects of
this invisible element of destruction
which, if left to itself, viii certainly
shorten the life of valuable city pro
perty.
THE damage already done by cleo
trolysfs to public works in England has
led to the establishment of regulations
to prevent such action in the future and
similar legislation may be expected in
this country if these conditions be al
lowed to continue. Prevention is simp-
" q question of additional expense.
THE incandesCent light currents I do
not consider as particularly dangerous
at the moment on account of their light
voltage, but it having been established
that the fraction of a volt difference Of
potential will cause electrOlytic action
1t simply comes down to a question of
time when these straying incandescent
currents will have to be seriously con
sidered.
1T is my opinion that ordinary eau
ton would suggest that periodical tests
should be made in every city where a
trolley road using a ground return is in
operation. In this way threatened dam
age by electrOlysis to water and other
pipes as well as to bridges might be ar
rested and finally CO17fvOITaG