Evening star. [volume] (Washington, D.C.) 1854-1972, 1894-02-19
THE TROllEY'S NEW TERROR
A Discovery That Has Just Been Made at
Philadelphia.
Underground Metal Pipes Ruined and
the Water and Gas Systems of
the City Imperiled.

Special Correspondence Of The Evening Star
PHILADELPHIA, Feb. II. 1894.
A new danger threatening philadelphia and
every other city in the Union on whlcn
trolley cars are run Is just now occupying
the attention of local engineers. 1t is
claimed that the effect of the trolley on the
| streets will be the speedy destruction of all
underground metal pipes. imperiling the
water and gas systems and causing enor-
nous expense to taxpayers.
William McDevitt is electrical inspector
for the Philadelphia fire underwriters and
for the Philadelphia fire patrol. AS prac-
teal expert in electrical work he is regard
ed one of the best. He has studied the
various systems in use in this country and
abroad, and in pursuing his Investigations
| he has visited every large city in America
and Europe. Upon Mr.. McDevitts return
from his last trip he made a careful report
of his observations OF underground electri-
cal currents upon gas and water systems
According to this report the great network
of underground pipes, upon which every
city depends for its water. was threatened
with destruction by subterranean electric
currents.
In explaining the escape OF electric cur
rents from the trolley rails, MIR. McDevitt
said to a Star reporter: The tracks upon
which the trolley cars run are charged with
~
is what IS termed high tension, 80 volts
being low tension, and the strength OF the
current used varying between these ex-
| tremes. If you will notice the laying OF the
tracks you will see that where the rails are
Joined they are riveted with iron plates,
and after that they are wired together. 1t
is necessary to keep the connection be-
tween the rails, otherwise the currents Will
be destroyed. The iron plates in themselves
are not sufficient. and for that reason the
wire reinforcement Is used.
Notwithstanding these double precau-
| tions however, ii Is not long before the
expansion and contraction impairs the con-
nections between the rails, and portion of
the electricity escapes into the ground. The
ground is very good conductor, and the
electric current that escapes into 1t is
therefore carried along. Wet ground Is
better conductor than dry. The current
will run along one stratum of made ground
until 1t nearS a stratum of earth that Is
more dry, when 1t will turn from it and
jump Into the pipes. In running along In
this way the electric current comes in con-
tact with some of the numerous under
grourd pipes used to convey our supply Of
water and gas.
Now what is called eiectroiysis takes
place. This action is similar to corro-
sion, but more speedy in it's action, and It
Is only a question of time when the pipes
must go. Curiously enough, the place
where the pipes give way and break is at
the very point where the erratic electric
current leaves them, not where 1t first
| strikes. OF course the pipes are affected all
| along the length of exposure to the current.
| but invariably the vulnerable point is where
| the electricity jumps OF.
THE trolley men all over the country
| have exhausted their ingenuity in devising
| schemes to protect the connections between
| the rails. 1t may be said that 1t is prac-
tically impossible to do this. The electric
! ity will escape at the fastenings connecting
| the rails and strike off into the ground in
| the way have described.
The time 1t takes to eat I'D ard DESTROY
| the pipes varies. OF course, but a year is
| sufficient to do the damage. 1 found such
l to be the case In Boston. You will see the
same result In Philadelphia. for the pipes
| will invariably give way entailing enormous
| expense In continuous repairs"