5.5.
TRANSMITTAL
The way the dispatcher transmits train orders and the way operators
receive and deliver them are illustrated in the example detailed in the
remainder of this paragraph.
It conforms to previous instructions and to
rules cited in appendix III and illustrates the planning that must be done
by the dispatcher. It shows how he must occasionally exercise his right to
restrict a superior train to assist an inferior one.
Refer to figure 1.1, which illustrates the single-track division, and to
columns 5, 6, and 8 of the single-track train sheet given in annex B. The
columns represent trains intended to illustrate a specific example. From a
standpoint of time and continuity, they do not dovetail with the remainder
of the train sheet.
Neither will No. 34 be found in the timetable in
appendix II.
The particular trains are used merely to present as many
situations as possible in the same illustration.
The delays are cited in
the text but not itemized on the train sheet.
a. Superior train restriction. When the dispatcher created Extra 4550
West at Conroy and authorized it to go out on the main track and proceed to
Maxey, he provided, by train order, for it to take siding at RK to clear No.
34. The latter's crew was given a copy of the order, and they knew, despite
the train's schedule shown in the timetable, that their train's superiority
would be restricted unless Extra 4550 West was at RK upon their arrival.
b. Dispatcher planning. Assume, however, that No. 34 is delayed at BO
for 25 minutes awaiting a mail truck connection, and a minor grade-crossing
accident at FV delays it another 30 minutes. To permit the RK meet order to
remain in effect would now mean that Extra 4550 West would probably be
delayed at RK for 40 to 50 minutes while waiting for No. 34.
This delay
would not be particularly serious to an extra train, but now something else
enters into the dispatcher's planning.
He has Extra 9510 West called at
Conroy at 1715 hours, as column 8 on the train sheet in annex B shows. It
is a heavy train and this particular engine is overdue in the back shop for
major repairs.
Consequently, the dispatcher would like to keep the 4550
well ahead of the 9510 to prevent the danger of the latter's engine stalling
on Windham Hill, shown on the map in figure 1.1. Previously, the dispatcher
had fixed a meet at MD for Extra 9510 West and No. 34.
c. Superseding an order. Because of the 55-minute delay to No. 34, the
dispatcher decides to put Extra 4550 West over
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