Evening star. [volume] (Washington, D.C.) 1854-1972, 1894-05-08

Experiment. With a subterrepe Troll.
ley On the Tenteytown Road.

Experiments With a Subterreue Troll.
ley On the Tenieytown Road.
Experiments are being made in a section
of the Bethesda Park electric railway of q
new underground system Of electric propul-
SION. The main feature OF the system is a
shallow condnits with a fiexibie cover sx-
tending over fits whole length. formed Of
metal plates hinged 20 one side of the con-
Quit and bound together on their under side
by a continuous band OF betting. From the
motor car depends a beveled wheel or pull
ley. which runs underneath the flexible COW
er and as the car proceeds keeps a small
section Of the conduit beneath the car open,
SO that the trolley may come into contact
with the exposed section of wire.
Mr. +. L. King, the inventor. gave an cx-
hbition Of his system last evening. Mr..
King conducted the trial personally and the
machine used was one of the freight cars Of
the Tenleytown railroad. The only addi-
lions to the freight car necessary to adapt
II TO the new system were a pulley TO open
the slot ahead OF the trolley. and a short
trolley reaching into the conduit.
The conductor Is laid in solid bed of IN
sulating material near the top OF a shallow
trench. The cover IS constantly maintained
In open position Immediately under the
motor. The depth Of the conduit is the
height OF the ordinary street eirder rail-
seven inches. Two ordinary steel channels
one on either side resting directly Upon the
ties VI Ine orulu6rN TOHQOe0 constitute the
wall OF the outer conduit. which is for drain
age purposes alone. Between these two ara
two smaller channels which support the
small conduit holding the wire and the COW
er which covers II over. These small cham
neis are perforated az regular intervals with
holes so that the space between them can be
used as a drainage for water as well as the
space on either side. the conduit being con-
nected with sewers at frequent intervals
The small or outer conduit containing the
wire is Immediately above the center chan
nels, the wire being half Embedded in Q
solid and continuous body CT Insulating ma
terial TIE upper side Of the Insulating ma
terisi is rounded or sloping on each side
from the center so as to 1T the inside OF the
cover.
The cover. which forms an important
part OF the device. rests upon this solid
insulating body, projecting over its SIDE
30 as to protect IL. The top part. which
supports street traffic over II. is a rnallea-
bic casting. nine inches long and six inches
wide. hinged at one side on a simple drop
forging. which Is riveted to the Hange Of
the small channel; these castings, consti-
tuting the top part of the cover are laid
one after another. one-eighth OF an inch
apart over the whole length OF the con-
dcit. Underneath these and attached TO
each casting is a continuous strip OF nexi-
BILE four-ply betting. water proof and q
perfect fnsulator. 1t constitutes the inner
or under part OF the cover. and when the
cover is down the wire is enclosed in insu-
iating material The mechanism used TO
maintain the cover in open position under
meath the car Is a small pulley, with a
beveled or rounded rim to fit the inside OF
the cover. which depends from the car. and
bears at right angles to the inside edge OF
the cover when raised. There are two of
these pulleys or rollers on each motor car.
SO that the cover. for the distance between
them is always opened full width. and Il
is In this space that the trolley is suspend
ed and makes a contact with the live wire
in the same manner as with the overhead
trolley. 1t Ia claimed that the device pro-
tects the wire fully from snow. rain or
sieet. as the cover is always open and
closed underneath the car. Among the ad-
vantages urged for the system is its cheap
ness as compared with other conduit sys-
tens. Mr.. King estimates the cost to be
$4,000 to $4,000 per mile. and says the
system can be put down on existing horse
the traffic.