The Saint Paul globe. (St. Paul, Minn.) 1896-1905, 1900-08-14
NEN CONDUCTIVE P|AN
BALTIMORE n OHIO ADOPT MUIR
PHY THIRD-RAH ELECTRIC
POWER SYSTEM
ADVANTAGES OF THE SYSTEM
Meeting of Traffic Officials at Chi
CaEo to Adjust Rates-New Ter.
1ttorT Opened I'm South
Dakota.

WASHINGTON. Aug. L. - Especially
An event of Importance in the ad-
vancement Of science has taken
plac here in the installation of
the Murphy third-rail system Of conduc-
tive electric power on the Belt line Of
the Baltimore & Ohio railway, between
this city and Baltimore. Although this
third rail will be put down along the en-
tire length Of the Belt line. in many in
stances it will be placed at the side Of
the track. There will be no overhead
wires, and 1t is also claimed that, ex-
cept when the motor is in the act Of pass
ing over 1t, no part of the rail will be
Tive" It will not be necessary to pur-
chase new motors, as the same shoe
which formerly conducted the current
from the overhead wires will now be
placed at the bottom of the engine, which
changes the method of contact
Each rail in this system is connected
with what is known as -solenoidal
switch, which has one winding Of coarse
and another of fine wire. When the car
is ready to start the switch is opened, and
there is no electrical connection between
the car and the feeder. With this con-
trolleF the motorman connects the motor
dynamo to the third rail and to the
ground, and the current passes through
the fine wire of the switch and causes 1t
the plunger rises and first makes contact
between the main feeder and the rail, and
then breaks the current of the fine wire
winding. When the controller is opened
the current comes from the feeder
through the coarse wire winding of the
switch to the third rail, and from thence
through the car motor to the ground,
causing the motor to revolve and the car
to move.
oh fc hald cI711 - IL
current in the coarse wire winding In
this closed condition the switch VII re-
main as long as the car is taking current
from the section to which the switch Is
connected. When the car leaves the sec
ton there is no longer a current passing
through the switch feeding it, and it falls
open, first breaking the electrical circuit
from the sectional rail through the fine
wire to the ground. The switch Is then
ready for the next car. The car being
thus started, the motor-dynamo is no
longer needed to operate the switches be-
cause the car is provided with two sets
OF shoes, which are connected and placed
sufficiently far apart to span the distance
from section to section TIL forward shoe
as it tmp1nges on a section subjects it to
the full-ltne potential drawing it's source
OF current from the rail preceding 1t
will then fall open from lack of current to
hold 1t up, and there is then no current
to break. The motor is provided with
what might be termed an Individual dy-
panIo to start it. After car gets under
he9dway, however, the current from the
third rail is depended upon altogether.
The motor-dynamo obtains It's current
'from~the storage battery.
The above information was obtained
from high official of the Baltimore &
Ohio railway here in Washington. He
said the road expected to reap large ben
efits from the new system Nothing can
tie up the road, and cars have even been
operated with ease when the track was
covered over in places with salt water.