EFFECTS OF TOW SEQUENCING ON CAPACITY AND DELAY AT A WATERWAY LOCK

Heuristic methods are presented for sequencing tows through waterway locks, including locks with two dissimilar chambers. The authors propose two algorithms for obtaining good initial solutions. Of these two, the shortest processing time first (SPF) algorithm gives priority to tows with lower processing time per barge, while maximum saving (SAVE) favors tows with the highest relative advantage at particular chambers. Improvements in delays and capacity that result from the use of these algorithms are evaluated by comparing them with a first come first served (FCFS) operation. Delay savings of up to 75.85 percent with SAVE and up to 79.73 percent with SPF are predicted at congested locks. A pairwise exchange algorithm is used to improve the initial solutions obtained with SPF and SAVE. The improved techniques, SPF with exchange (SPFX) and SAVE with exchange (SAVEX), further reduce the average barge delay. While SPFX does not significantly improve SPF, SAVEX reduces average barge delay by up to 26.5 percent compared to SAVE. Among all these methods, SPFX yields the smallest barge delay. When upstream and downstream flows are unequal, the delay savings can be even greater.

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  • English

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Filing Info

  • Accession Number: 00716424
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Feb 1 1996 12:00AM