The daily morning journal and courier. [volume] (New Haven, Conn.) 1894-1907, 1895-07-12
the BA1r1MoRE TUNNEL.

Facts and Figures Giving Full Descrip-
tion of the Great Improvement.
One of the great electric locomotives
which are to haul both passenger and
freight trains through the Baltimore
and Ohio tunnel at Baltimore has
reached its destination, and Is now I'M
dergoing series of tests upon the line.
So far the tests have proved satisfaeto-
ny.
The tunnel through which these loco
motives will pull the trains runs under
the city of Baltimore, and was con-
structed for the purpose of giving to
the Baltimore and Ohio railroad a clear
route through to the north. Previous
to its construction all trains on this
railroad going north were ferried across
the harbor from Locust Point to Canton.
The saving Of time effected by the SER
vice through the tunnel will allow the
railroad to compete with the Pennsyl-
vania or Union lines on equal terms,
The tunnel is the longest soft earth
tunnel in the world. 1t is 1889 feet, or
nearly one mile and a half long, twen-
ty-seven feet high and twenty-five feet
wide, and its total cost is set down at
$7,500000. 1t was begun in September,
1890, and finished early this year. 1t
runs under Howard street, one of Balti-
more's principal thoroughfares, and
was driven without any interference to
the surface traffic, the vertical shafts
being sunk to the tunnel through the
cellars of houses along its line. The
only severe cave-in occurred in the vi
cinity of the Baltimore City college,
which was ruined. A new college was
built by the contractors on the site of
the collapsed building.
Before the tunnel was finished the
question of its ventilation became ur-
gent. If it could not be ventilated the
travelling public would not patronize 1T,
prefering to travel by another route
Many plans were submitted and dis
cussed. Gable traction as in the Gale
DOMAIN railway at Glasgow, Scotland
was suggested. but rejected as also
were a number of other impracticable
expedients. Finally, the suggestion of
the General Electric company that cleo
trio, instead of steam. locomotives
should be used, was adopted, and an
order was placed for three electric loco
motives capable of handling the heav-
lest passenger and freight trains which
the Baltimore and Ohio railroad would
be likely to carry. One of these is fin
ished and running, and the other two
are under way at Schenectady.
The electricity necessary for the ope-
ration of the locomotives and the light
ing Of the tunnel and stations is gene
rated in the power house. a large orc
story building on Howard street, racing
the Camden street station The south
end of the building is occupied by the
water-tube boilers, of which there are
twelve of two hundred and fifty horse
power each. The draft for the fires is
produced by two large revolving fans
at the base Of the squat-looking stack.
"A brick partition divides the engine
room from the boiler room.
The electric power plant consists of
four large General Electric dynamos
driven BY four tandem compound Rey-
nolds-Corliss engines. The dynamo ar
Each dynamo is known as a 500
kilowatt machine. This is the electric
equivalent of about six hundred and
SIAly-SlA 1lUISG pOWGI. IAGy IGVOiVS dl
one hundred and ten revolutions per
minute, and deliver the current to the
locomotives at "a pressure of seven hun
dred volts.
The dynamo is huge circle Of cast
steel ten feet in diameter, having ten
poles, all facing inward. Each pole
carries spool of wire which forms the
winding, and the circle of steel, poles
and windings form what is known as
the magnetic field of the generator.
Revolving in the center of these In
wardly projecting pole pieces is the
armature, built up of a number of iron
Nominations, arranged upon a circular
support or spider to form a spiral, each
lamination being, of course, insulated
from the next The outer surface of
the large cylindrical body is slotted,
and each slot receives copper bar
which is wrapped in insulation. These
bars form the armature windings, and
each is connected to the commutator by
metal strip.
The electricity is collected from the
commutator by ten brushes, which are
all dropped upon 1t, or lifted from 1t
simultaneously by the movement of a
lland-whee1.
The electric lighting plant consists of
eight Thompson-Hous arc light dy-
namos, furnishing current for the arc
lamps in the stations, and two alterna-
ting current dynamos for the incandes-
cent lights in the tunnel
The output from the power plant Is
controlled from a white marble switch
board on a platform at the south end of
the room. This board carries the ne
cessary controlling and measuring in
struments, as we'll as the automatic
devices to prevent injury to the dyna-
mos from short circuit lightning OF
other accident. The lighting circuits
are controlled from a smaller board
also Of white marble, facing the light
ing plant.
From the switchboard the current is
carried to the outside of the power
house, over eight heavy cables of copper
connected to the overhead structure
and to three feeder cables, also of cop
per. The outgoing current is positive
the returning current, which comes
back to the power house through the
rails and return cables of copper, being
negative. That the return of the cur
rent may be effected over an uninter-
rupted conductor, and no leakage &C.
cur, all the rails are connected to each
other by heavy band of copper rod.
Tho electric locomotives will ODerate