Note that this railway net is a single-track line that connects
the port terminal with railhead A and passes through stations X and
Y.
Both X and Y have adequate sidings.
Because the track and
facilities from Y to A are subject to guerrilla action, positive
block operation is used for this segment of line. However, since the
line from port terminal to Y is reasonably secure from enemy attack,
permissive block operation is being used for that segment.
Our
problem is to move train No. 44 from its position at the port
terminal to A.
Normally, any train moving toward the forward area has priority
over trains headed to the rear. So, No. 44 leaves for X and is the
only train on that block of line.
Trains 109 and 533 have both
departed Y for X.
This is allowed in permissive block operation.
Train 91 is on a siding at Y and cannot proceed toward A until No. 77
has reached A because positive block operation allows only one train
within any block at one time. Since train 551 is rear-bound, it must
wait at A until both 77 and 91 reach that terminal because they have
priority over 551.
Now for the next move, as depicted in figure 3.3. Number 109,
reaching station X, takes the siding there; No. 44 reaches X and
waits there for the arrival of 533.
Meanwhile, No. 77 reaches
railhead A and No. 91 departs Y for A. Number 533 is delayed getting
to X because of a temporary breakdown.
In the next move, is shown in figure 3.4, No. 91 arrives at A
and No. 551 leaves A for Y.
Number 533 arrives at X and takes a
siding. Number 44 leaves X and arrives at Y where it must wait the
arrival of No. 551.
The stationmaster at Y learns that No. 77 is
ready to depart railhead A on an empty run to the rear. He orders 77
to hold at A because No. 44 is headed toward the forward area and has
priority over No. 77. When No. 551 arrives at Y, No. 44 proceeds to
A. Our problem is now complete.
Although manual block operation is less efficient than train
order and timetable, it provides a relatively safe method for early
train operations in a theater.
Many foreign countries use manual
block operation.
3.7. TRAIN ORDER OPERATION
A more efficient and flexible method is train order operation.
It is started after dependable communications have been established,
and adequate railway sidings have been provided.
Trains operate on
orders from the train dispatcher at the railway battalion's
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