Organizing Railway Transportation

Several problems exist in the current rail freight rate system . We must accumulate data on these problems , study them in detail and gradually adjust them so that rail rates can better fulfill their function of encouraging production ...

Author: China. Tie dao bu

Publisher:

ISBN: UOM:39015012068352

Category: Railroads

Page: 469

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On the Problem of Sorting Railway Freight Cars

Otherwise, extending the current chain continues with the next type. A chain also finishes whenever the first type of the next outbound train is reached. This procedure is formally described by Algorithm 1. It receives as its input the ...

Author: Jens H. Maue

Publisher: Cuvillier Verlag

ISBN: 9783736939387

Category: Computers

Page: 174

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In this thesis the algorithmic foundations of a particular sorting problem from railway optimization are studied. The addressed problem is called train classification, and it refers to the fundamental procedure of rearranging the cars of several trains into other compositions of different orders comprising new trains. The train classification methods applied today present rather conservative approaches, and there is a lot of room for systematic improvement by applying optimization methods. The sorting processes are performed according to plans prepared in advance called classification schedules. They are conducted in specific railway facilities called classification yards. Without expensive redesigns of existing classification yards, the dwell time of railway cars can be reduced by accelerating the core classification process itself. To this aim, the combinatorial structure of the sorting processes are studied in this thesis in order to provide algorithmic solutions for the abstract problems derived from the practical setting with formal proofs of their efficiency. Conversely, the gained insights are applied to real-world problem instances to show that the theoretical approaches work in practice and improve on the methods applied today. First of all, a novel encoding of classification schedules is presented. This does not only yield an efficient representation of train classification schedules, but it also allows characterizing feasible classification schedules and is applied to derive an algorithm for computing optimal classification schedules for the core version of the sorting problem. Several practical problem settings then yield further restrictions on a feasible schedule, which are shown to translate to formal constraints in the above mentioned representation. Successful solution approaches are then developed for various infrastructural as well as operational constraints. The former particularly cover different dimensions of limited track space, the latter include train departures and track space varying over time. The approaches comprise efficient exact and approximation algorithms and also integer programming models that allow integrating several such constraints simultaneously. Then, another problem variant deals with the robustness aspect of uncertain input, which here corresponds to disruptions in the railway network resulting in trains arriving delayed at the classification yard. A model is introduced in which a prepared schedule that became infeasible by an arising disruption is adjusted by inserting some additional steps into the sorting process. Without any assumptions on the amount of disruption, this robust problem variant is shown to be NP-hard. Still, a generic method is provided for the general setting, from which an efficient algorithm for a realistic model of disruption is derived. The developed theoretical approaches are compared to each other and evaluated experimentally using various synthetically derived and real-world traffic instances to show that the achieved insights and solutions are relevant in practice.
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Railway Age

Mr. Budd will speak on current railway problems as related to engineering . Aitchison Guest of Traffic Club for Anniversary Clyde B. Aitchison , Interstate Commerce Commissioner , was the guest at a luncheon of the Traffic Club of ...

Author:

Publisher:

ISBN: UOM:39015010880394

Category: Railroads

Page:

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United States Railway Association Preliminary System Plan

The fundamental industry problems set forth in both the latest USRA and the RSPO reports must be addressed in any long term solution to the current rail problem . In my opinion , attaching the credit of the U. S. Treasury to any ...

Author: United States. Congress. House. Committee on Interstate and Foreign Commerce. Subcommittee on Transportation and Commerce

Publisher:

ISBN: LOC:00183873180

Category:

Page: 1114

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Current Topics in Artificial Intelligence

Several realistic instances of the problem have been verified as well as different traffic conditions and train configurations. The method can be applied to any railway line and does not require a specific configuration in the railway ...

Author: Roque Marín

Publisher: Springer

ISBN: 9783540459156

Category: Computers

Page: 482

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This book constitutes the thoroughly refered post-proceedings of the 11th Conference of the Spanish Association for Artificial Intelligence, CAEPIA 2005, held in Santiago de Compostela, Spain in November 2005. The 48 revised full papers presented together with an invited paper were carefully selected. The papers span the entire spectrum of artificial intelligence from foundational and theoretical issues to advanced applications in various fields.
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United States Railway Association Preliminary System Plan Hearings Before the Subcommittee on Transportation and Commerce of the 94 1 May 5 6 8 9 12 13 14 15 16 and 21 1975

The fundamental industry problems set forth in both the latest USRA and the RSPO reports must be addressed in any long term solution to the current rail problem . In my opinion , attaching the credit of the U. S. Treasury to any ...

Author: United States. Congress. House. Committee on Interstate and Foreign Commerce

Publisher:

ISBN: STANFORD:36105021022301

Category:

Page: 1114

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