Passengers who want to take an intercity journey via public transport in Greece, should use either the Railway Network (TRAINOSE) or the Intercity Bus network (KTEL). 

However, neither one of those networks cover all the possible transitions from each city to another throughout the country. Thus, some journeys involve changing modes— from say a bus to a train or vice versa (co-modal travelling or co-modality). That can only happen in stations that are part of both TRAINOSE and KTEL (intermediate nodes).  

Although co-modal travelling is often necessary, daily schedules of TRAINOSE and KTEL do not necessarily support co-modality due to many reasons (e.g. operational). This results frequently in long waiting times at intermediate nodes.  

GYM, utilizing its network (that involves TRAINOSE and KTEL), uses advance mathematical modeling to developed synchronized timetables between TRAINOSE and KTEL, in order to adjust daily schedules and minimize waiting times at intermediate nodes.  

The Railway Network is consisted of approximately 300 stations, 30 of which represent cities with railway and intercity bus stations, thus there are 30 intermediate stations that allow transition.  Each one of these 30 intermediate stations, are destinations and/or starting points of an Intercity Bus line. 

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In addition to the intermediate stations, KTEL has to serve a number of other bus stations, the arrival and departure times of which play an important role in the synchronisation process. Every intermediate station has its own timetable as part of the KTEL network, serving the local transportation needs, usually from a city to the nearby villages. A mixed integer linear optimization model has been developed to analyze the potential synchronization of TRAISOSE’s timetable with those of KTEL operators.  

The analysis shows that the total waiting time for a transition between KTEL and TRAINOSE could be reduced by an average of 12% and in some case could be reduced up to 25-30%.