Transit timetables as multi-layer networks

There have been many studies on public transit networks with journey planning as an objective. Journey planning requires computation of feasible itineraries in least number of steps. Appropriate representation of transit networks allows us to study them from the perspective of transit operators and users. Optimal transit network representations help achieve both the objectives. We present multi-layer transit network as one approach to reduce the number of steps required in the itinerary computation. We present algorithms for creation of multi-layer network representation from public transit timetables. Our proposed algorithm is capable of considering shared transit vehicles while creating the multi-layer network. We apply our algorithm on the timetable of the Indian Railways Network (IRN). We create a three-layer network consisting of space of stations, space of stops and space of changes. We also compare the network characteristics of the space of stops and the space of station networks generated from the timetable of IRN. We show that the space of stops network is a useful representation for the passengers of IRN where as the space of stations is a useful representation for the operations team of IRN.