Modelling Impact of Defects and Faults on Railway Punctuality

To prioritise maintenance and renewal in the railway infrastructure it is required to have a good understanding of the impact defects and failure have on punctuality.The paper presents and compare two different assessments methods.The first approach is based on a network model where each train journey is modelled in terms of speed, acceleration, opportunities for crossing etc.The case study is performed on a Norwegian single track line, hence the limited places for crossings will be important in the model.For such a simulation model it is then possible to induce a fault or a degradation which either represent a full stop, or speed reduction.Depending on "where and when" the failure or defect occur, the consequences may vary.The second approach is based on analysis of statistics.In Norway there is a system here a so-called "event ID" is linked to each train that arrives late to a station.This means that the train operations centre is assigning a specific condition as a reason for the delay.This provides lists of "who to blame" for the punctuality.Fault and defects in the infrastructure is part of this picture, but in addition comes delays due to failures of the rolling stock, other train being delayed causing delayed departure etc.