protects its rear by stationing himself far enough back to stop any
approaching train. On single-track lines, the forward end of the train must
be protected in the same way.
When the work-train engineer pulls into a
siding and clears the main, he sounds an appropriate number of blasts on the
whistle. This is called "whistling in" the flagman. Before the train again
blocks the main, the engineer sounds a specified number of blasts and the
flagman again goes out to flag. This is called "whistling out." The number
of blasts varies according to the direction in which the train is headed and
to the number of main tracks.
The alternate whistling in and whistling out, which occurs when a
work train clears and blocks the main, involves a hazard that operating
rules do not stress and safety spokesmen seldom point out. The danger stems
from a possible human failure during the flagging--a danger which is
probably best illustrated by the following true story.
An experienced flagman was assigned to flag for a work extra on a
single track not having block signal protection. The work train had about 6
hours work in one location approximately 251 meters from a siding.
train crew held orders to protect itself against eastbound extras only. The
conductor was able to station himself close to a wayside dispatcher
telephone and, as unscheduled trains came within a few kilometers of the
area, he would have the work train enter the siding and call in the flagman.
This would relieve the flagman and he'd return to the side of the tracks and
let the approaching train by.
After it passed, the work-train engineer
would whistle out the flagman and then return to the main track; the flagman
would again assume a position in the center of the track ready to stop all
eastbound extra trains.
Several hours passed during which the flagman had been whistled out
and in perhaps a half-dozen times while as many trains safely passed. Late
in the afternoon, a fast, high-priority freight appeared in sight of the
flagman about a kilometer away. He, in turn, was a kilometer from his train
which was around a curve and out of sight. The flagman, sitting on a pile
of ties, got up when he saw the approaching train and walked to the center
of the track. He looked in both directions and returned to the tie pile.
Soon he got up again, walked over to the track as if to flag the train, and
suddenly turned around and returned to the pile of ties. The engineer on
the approaching train, expecting to be stopped, had eased off on the
throttle, but he resumed full speed when the flagman walked to the side of
the right-of-way a second time. A kilometer up the track