The Saint Paul globe. (St. Paul, Minn.) 1896-1905, 1901-09-17
MAINS EATEN AWAY
INQUIRY INTO DAMAGE DONE BY
STREET RAILWAY CURRENTS
ALMOST COMPLETE
REPORT WILL BE EXHAUSTIVE
EIectrOIysis Arising From Return
ing Current Has Greatly Affected
Mains-TwO Remedies Will
Be Proposed.

Return currents from the dynamos OF
the city railway company have for a
number of years past been instrumental
in electro-plating the ground along the
line of the city water mains with a lib
eral deposit of iron, and incidentally the
mains have suffered considerably from
the process. This has been recognized,
and for year engineers have been con-
Quoting an investigation as to the extent
of the damage which has been done 10
the big pipes in consequence. This work
is almost finished, according. to an eX-
pert who accompanied the engineers en-
gagged in collecting data for use in an
other city. He says a number of GU
rious observations have been made in
the course of the twelve months of care
full inquiry, and that the results will be
embodied in a report which will shortly
be presented to the city engineer
In some instances it was found that
sixteen-inch pipes, seven-eighths of an
inch in thickness, have been almost
eaten through with the action of the
electricity. In other cases pipes not
half so thick were almost uninjured the
difference being due to variation in the
conductivity of the earth The corrod-
ing process has not been limited to the
iron mains, as in hundreds of instances
lead plumbing connections from mains
TO dwellings, were IOu1Q TO nave SuHGreQ
just as severely between the mains and
the. point where the lead pipes enter the
houses.
HOW MAINS ARE DAMAGED.
Some misapprehension exists in the
minds of many persons as to the exact
manner in which the mains are damaged
by the currents; it is thought by many
that the street railway company has
suEreptitiously made connections be-
tween .Ae rails and the mains and that a
convenient return has been provided for
in this way. AS matter of fact no such
attempt has been made. nor is
it necessary to resort to any
such sexpedient. The earth is in most
instances a good enough conductor to
carry the surplus current from the rails
to the pipes It appears that there is
no damage done to the mains at the
point where the current enters them,
but that 1electrolyttc action is set up
where the electricity leaves the pipes in
it's passage to the negative pole of the
dynamo whence it emanates. This &C.
ton is precisely similar to other electro
plating, and in many instances the earth
has been found to be generously impreg-
mated with iron for several feet around
the pipe. This iron Of course comes
from the mains, and the natural conse-
quenee is that the thickness of the pipes
is greatly reduced, and in time they are
completely. worn through
The current which finds its way back
to the dynamo by way of the pipes is
what the rails cannot carry, and only
when these are overcharged does the
fluid seek another outlet. The earth
Is fair conductor, and the pipes are
readily reached. When tue current
leaves the iron conductors electrolysis is
set up at the point where the electricity
leaves it, and the iron is deposited in the
soil all around
The expert who has been following
the Investigations of the city engineer
is of the opinion that the report to be
presented to the city engineer will be so
conclusive that absolutely no loophole
of escape on the part of the street ralI-
way company will be left. large
number of photogTa phs have been Sc
cured and chemical and other data col
lected. The supreme court of the onited
States has been called upon to decide
similar cases on seven different occa-
sionS and In every instance the street
railway side has lost
In Cincinnati, where the currents from
the street railways are particularly de-
structive to the mains, a compromise has
been effected, and the railways pay all
bills for damage done in this way 1t IS
thought possible that the same course
event of the company deciding to fight
the results of the investigation, expen-
sive litigation is inevitable, but if pre-
cedents are to be relied upon it would
seem that there is little danger of the
ultimate verdict being against the city.
REMEDIES THAT ARE POSSIBLE.
AS a remedy to the existing order of
things two methods are possible. One is
the insulating of the motors at the
axles of the wheels and returning the
surplus current by means of an extra
trolley wire. other is one which
is in use at Buda Pesth and in one or
two cities in the United States 1t in
wolves the discarding of the trolley and
the substitution of an underground sys-
tenn of supply and return. The current
is fed to the motors by an underground
trolley, and returned through slot
placed midway between the rails. The
fluid passes through copper bars by
means of a brush connection and is con-
veyed to the dynamos by cables for the
purpose. This is a most expensive sys-
to install, but once in place 1t Is by far
the cheapest to maintain.