Q2 Z2,(Q2) Z2(Q2) - Institute for Water Resources - U.S. Army

particular . trip', that tonnage may be achieved in a variety of ways;
e.g., fewer barge& with-deeper drafts, more barges' with smaller drafts,
and different . arrangements-of 4 given number of barges. It is desir.;.
able, therefore, to have a formulation of C that will aceount for '
these possible alternatives. This is discussed in the next section.
There remain a large number of components of the tow process function
for which methods of eitimation must be developed. Functional forms
for V f' D a ,.D d' T a' and T d are developed below based upon the analysis
of Chapter III and specific tractive-effort and drag-force functions
applicable to barge tows. This chapter also develops procedures for
estimating T L , T m , T b , T o , and N. Locking time is estimated by a
relatively simple queuing model. Make-tow and break-tow time are es-
timated from towboat log data by least-squares procedures. Miscel-
laneous delay 'time is estimated from aggregate delay data provided by •
a barging firm and, in addition, utilizes the analysis of a tow in
motion which was developed in an earlier section of this chapter.
Finally, an estimate of No is obtained from towboat log data. More- .
over, these formulations of the inputs to the process function will .
be amenable to changes in variables under control of the firm (e.g.,.
horsepower of towboat, draft of barges, number of barges comprising .
a flotilla, etc.) as well as variables under control of the Army ,
Corps of Engineers (e.g., waterway depth, waterway width, stream
velocity, and size of locks).
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