IT Systems in Public Transport

5 The Traffic Network and Routes

Network = Graph

Public transport requires a fixed network of stops and connecting paths. From a mathematical point of view, you are dealing with a directed graph, i. e. every connecting path is represented by two edges – one for the outward journey and one for the opposite direction. A single-track rail connection would still have two edges¹. The natural way to represent a transport network is to regard the stops as nodes and the connecting paths as edges in the graph. However, you can also choose the opposite representation.²

Incremental network planning

In Germany and many other European countries, network planning only takes place incrementally nowadays, i. e. when modifying and expanding the transport network, ...