The problem of transport timetables re-scheduling refers to the adjustment of the execution times of trips. Trips, in most cases, are services that utilize the different means of transport in order to move people, and in some cases commodities, from one place to another.

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The purpose of appropriate timetable scheduling lies on assessing robustness, i.e. creating a timetable in which small delays during everyday operations can be absorbed and therefore possible delays in the overall schedule can be limited. When creating a network transport schedule, a scheduler attempts to create appropriate departure times, taking into account the necessary frequency, the assignment of trips and the synchronization of arrivals. The widespread approach considers factors from passengers’ perspective, dealing with the minimization of travel times required. The initial timetables are re-examined periodically to correct inefficiencies and infeasibilities and to keep them updated according to demand.

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Several approaches for timetables’ re-scheduling have been proposed. For example, a rescheduling problem could be solved to rearrange the starting times of trips for a bus service operator in order to minimize the trips executed, and thus cost of operation, and, at the same time, maximize profit. In other cases, sub-problems of rescheduling deal with the benefits of the person that travels or the customer of the travel service operator. The ease of travel is a criterion in most cases, where travelling should be made as comfortable as possible for the customer. Finally, there are case-specific rescheduling problems that would take under consideration parameters such as the use of specific vehicles for specific parts of the road network and can even include transports services of products, where the attributes, such as size and capacity, are very important. Re-scheduling practices can be utilized also for environmental benefits, where trips and services are re-organized in such a way that the new schedule that occurs has direct effects in the environment that is interconnected to the transport network of operation.

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In LIFE GYM project, a re-scheduling problem was solved for the Greek, Czech and Slovak public transport network, concerning the re-arrangement of train and bus services in such a way, so that the passengers of those trips and routes, would spend less time waiting at intermediate nodes of the networks between trips, when they have to use more than one transport mean. The result of the analysis of the network and the services is a proposed schedule which transport operators could adopt in order to provide better services to their customers.