The Idaho Republican. [volume] (Blackfoot, Idaho) 1904-1932, 1911-06-16
why Electric Trains Start Smoothly


to get away SO smoothly?
The green motorman, starting his
car in neck-breaking fashion, which
seems to jerk the car-body from the
trucks, does not know the simple
secret of starting an elevated train.
On elevated railways, subways and
steam roads electric cars
are usually run in the form of trains
instead of single units. In this way
one motorman can run the whole
train. If this train is started proper
ly it seems to glide into motion and
goes skimming along the rails with
out discomfort to passengers, loss of
power or damaging the electrical
Trains of six, sven or more cars
are run as unit in each train and
no one car has power enough to
start the whole train quickly enough
to meet the requirements of modern
rapid transit. So in train of seven
cars it is necessary to have at least
four of the cars equipped with mo-
tors. Not only would it be expensive
to have motorman on each Of these
cars, but even should this be done.
the troubles of the single car would
be multiplied by four. They would
mot start together and one set of
motors would for an instant be try
ing to do the work of four, and then,
perhaps, all would get in at once
and the train would give lurch that
would take the strap-hangers off their
feet like a row of dominoes. Power
would be wasted and machinery in
jured. ..
In order to get all the cars of a
train to start at the same time and to
start as rapidly as possible without
discomfort or damage, the whole OPP
Grafton is made automatic. The mo-
torman sits in his little cab in the
front car and moves handle on the
little cylinder to one side and in
stantly, in all the cars, switches,
worked by air pressure, are connected
so that all the motors start together
Without further motion on the part
of the motorman these switches are
then closed step by step so the cars
gain more and more speed until they
have attained about half the best rate.
Then, if it is desired to increase this
speed, the motorman is called upon
to make second motion and throw
the handle TO the second notch.
Smoothly all the cars throw on their
additional power in gradual mere
ments, till full speed is reached. The
rate at which the speed increases is
beyond the power of the motorman
to control. 1t is fixed at the shops
so that all he has to do is to start
the mechanism working and let the
compressed air and the magnets take
care of the rest.
For example, the. valves can be Sc
so six-car train will come over from
rest to half-speed in ten seconds, and
it will do this every time, regardless
: of the man in the cab. All the mo
tors do their proportional share OF
the work and the valves are so ar,
ranged that the air is not permitted
! to close a switch, to give more powe;
to the motors, till the train has in,
creased it's speed enough so the
throwing of additional power will not
cause jump in speed.
In these automatic systems the mo
torman does not work at all with the
current that runs the motors. He
simply turns on and off the current
that comes from a small storage bat
terry on the train. This current oper
ates small magnets which open valves
admitting compressed air from thu
air-brake pipes into small cylinders
By this compressed air the switches
which handle the main current from
the third rail or trolley wire to tho
motors are opened and closed in regu
lar order. They are so interlockef
that it is impossible to throw the
wrong one first or TO throw them II
anything but the right order and a
the right times to give the pre-de
termined speed.
Furthermore, in the latest systems
if the motorman should take his hanC
off the little handle in the cab thu
train would be brought a stop, TO
it is necessary to actually hold it il
place to keep the current on, sprinE
tending to throw it back to the stop
|ping position at all times. This ar
rangement is provided sc that IT !
motorman should faint or fall asleep
due to overstrain, the cars would sto'