so. When a dispatcher wants a train to stop, wait for, and meet an opposing
train, a signal light shows where and when to make the stop.
opposing train clears, the stop signal changes to proceed.
Dispatcher Working at CTC Panel.
This system eliminates reading, repeating, interpreting, and remembering
the provisions of numerous train orders that would ordinarily be received as
much as 2 hours before the time to carry them out. The crew receives visual
orders, as it were, from the signal lights at the time and the point where
they are to be executed. Rules 86 and S-87 do not apply in CTC territory.
The following subparagraphs discuss the CTC's system control panel, safety
features, and advantages, but before that discussion begins, electric
interlocking controls are explained.
Electric interlocking, an early form of CTC, is used on foreign
railroads. The layout may extend for several kilometers on each side of the
control tower from which the interlocking plant is operated by a towerman.
However his control ends where the tracks join the area under the control of
A towerman at work is shown in figure 1.6.
installations, generally used at congested junctions and terminals, allow
the dispatcher and the tower operator more flexibility in handling trains
and yard movement in yard limits.