connected to measure the output of the main generator.
22. Multiple Unit Operation
Each segment of the band shows the allowable load-
a. Application. Two to four locomotives may be
time limits which may be carried by the generator and
coupled together and operated as a single unit after
the motors connected in parallel with it. After the time
connections are properly made. In addition to the
limit in any one portion of the overload range is reached,
conventional coupling of locomotive drawgear and air
the generators and motors have reached their maximum
lines, the electrical control circuits of the locomotives
allowable temperature, and their load must be reduced
must be connected. A jumper for this purpose must be
to the continuous range or severe overheating of the
firmly plugged into the receptacles at the end of the
motors will result. Operation in any one of the overload
locomotives. The controls are then set so that the
ranges, as shown on the dial, for the maximum time
power and the brakes on all locomotives are controlled
specified, is permitted again after a cooling period, at
from only one cab.
The locomotive from which
idle position, of 30 minutes duration.
operation is controlled is called the leading unit and any
e. To Stop Locomotive. Move the throttle to the
coupled locomotives are called trailing units. Certain
"OFF" position and apply the airbrakes in the usual
alarm and protective devices and certain auxiliary
manner.
controls such as sanding are connected through the
jumper, but the power plants and heavy duty circuits of
f. To Reverse Locomotive. In order to change the
the coupled units remain entirely independent of each
direction of motion of the locomotive, place the throttle
other.
in "OFF" position and bring the locomotive to a stop;
then throw the reverse handle to the position required.
b. Operation.
(1) If the locomotives are not already coupled
Caution
together and it is desired to operate two or
With the locomotive in motion,
more locomotives as a single unit, start
power must never be applied with
the engines by going to each locomotive
and starting the engines as described in
reverse handle in the position
opposite to the direction of the
locomotive motion. If recourse to
(2) Couple the locomotives mechanically in
such action is necessary to stop the
the usual manner. Return all throttle and
reverse handles to OFF. Couple the
locomotive abruptly, serious damage
locomotives electrically by means of the
to the motors is likely to result.
train line jumpers. Open the control and
fuel pump circuit breaker on the trailing
g. Wheel Slipping.
locomotive or locomotives. This prevents
(1) If wheel slipping occurs, move the throttle
currents from circulating between the
handle toward the idle position until the
batteries of the locomotives and
slipping stops.
automatically causes the engines to stop
(2) Never apply sand while the wheels are
on any locomotive behind a BREAK in
slipping as this could cause a broken
case a coupler breaks and the train parts
traction motor gear. Always use sand
in operation. Couple all auxiliary train line
sparingly as excess sand can be injurious
connections.
to the traction motors.
(3) If the locomotives have already been fully
h. Leaving the Locomotive.
connected but are shutdown, the engines
(1) Stop engines by operating engine
must be started by going to each
shutdown pushbuttons.
locomotive and starting the engines in the
usual manner. On all locomotives, close
(2) Place reverse handle in OFF (remove to
the battery switch, auxiliary generator
lock controller).
cutout and engine alarm cutout switches.
(3) Open control circuit breaker.
See that the lubricating oil and fuel oil
(4) Open battery switch.
systems are set properly. On the trailing
(5) Set handbrake.
locomotive or locomotives, set the
(6) Properly protect water system in cold
controller handle in the OFF position.
weather.
(4) On the lead locomotive, close the control
10
