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Planning Problems in Intermodal Freight Transport ...

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present a modell<strong>in</strong>g approach focus<strong>in</strong>g on the comparative evaluation of conventional and<br />

advanced rail/road term<strong>in</strong>al equipment. The modell<strong>in</strong>g tool set consists of a micro-model to<br />

compare alternative term<strong>in</strong>al designs and a macro-model to analyze the attractiveness of the<br />

<strong>in</strong>termodal transport cha<strong>in</strong>. The micro-model <strong>in</strong>corporates an expert system, a simulation<br />

model and a cost calculation module. The expert system assists users to form technically<br />

sound term<strong>in</strong>al designs. The simulation model is used to determ<strong>in</strong>e tra<strong>in</strong> and truck service<br />

times, which are then compared to predeterm<strong>in</strong>ed service criteria. For each accepted term<strong>in</strong>al<br />

design a cost-versus-volume curve is calculated. Truck wait<strong>in</strong>g time costs are taken <strong>in</strong>to<br />

account. The micro-model reveals that each design is effective for a certa<strong>in</strong> cargo volume<br />

range and is restricted by capacity limitations. The effects of an efficient term<strong>in</strong>al operation <strong>in</strong><br />

conjunction with advanced rail operat<strong>in</strong>g forms is further <strong>in</strong>vestigated <strong>in</strong> the macro-model.<br />

The discrete event simulation model of Rizzoli et al. [12] can be used to simulate the<br />

processes <strong>in</strong> a s<strong>in</strong>gle term<strong>in</strong>al or <strong>in</strong> a rail network, connect<strong>in</strong>g several rail/road term<strong>in</strong>als<br />

through rail corridors. The objective of the model is to assess the impact of various<br />

technologies and management policies to enhance term<strong>in</strong>al performance and to understand<br />

how an <strong>in</strong>crease <strong>in</strong> <strong>in</strong>termodal traffic affects term<strong>in</strong>al performance.<br />

Two studies discuss the simulation of rail/rail <strong>in</strong>termodal term<strong>in</strong>als. Meyer [13] faces<br />

the design problem of a rail/rail term<strong>in</strong>al <strong>in</strong> a hub-and-spoke system for the exchange of a<br />

maximum of six tra<strong>in</strong>s at a time. In addition, the term<strong>in</strong>al should be able to handle a limited<br />

volume of rail/road exchanges. Dynamic computer simulation with Petri-net applications was<br />

developed to determ<strong>in</strong>e required capacity for cranes and <strong>in</strong>ternal transport systems, and the<br />

most efficient arrival pattern of tra<strong>in</strong>s. Bontekon<strong>in</strong>g [14] develops a simulation model to<br />

perform a systematic comparison between various hub exchange facilities <strong>in</strong> an <strong>in</strong>termodal<br />

rail network. Her ma<strong>in</strong> objective is to identify favourable operational conditions for an

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