Analysis of capacity on double-track railway lines
2010 (English)In: Transportation planning and technology (Print), ISSN 0308-1060, E-ISSN 1029-0354Article in journal (Refereed) Accepted
In Sweden rail traffic is almost never separated according to speed. On several double-track lines the mix of heavy freight, regional and high speed trains imposes severe capacity problems. In order to evaluate the capacity for different traffic mixes a combinatorial model, TVEM (Timetable Variant Evaluation Model), has been developed. In this model both the infrastructure and the timetable are modelled as variables. The traffic is divided into train patterns according to a presumed regular timetable and then systematically scheduled in different time locations. The timetable variants are evaluated with regard to: mean values of capacity that give the number of trains/h for the required mix, variance measures that show how the capacity depends on the timetable and scheduled delays that show the extension of run times imposed by overtakings.
The paper shows how the important distance between adjacent overtaking stations can be sampled from Weibull distributions. TVEM has been used to evaluate three different operational cases with mixed traffic. The analysis shows that the impact on capacity from the infrastructure increases with speed difference and frequency of operation for the passenger trains, while the importance of the infrastructure decreases when traffic is more homogeneous. The impact from the timetable is strongest when the speed differences are low and/or the frequency of passenger trains is low. Capacity loss due to increased speed differences can be compensated for with additional overtaking stations. The slower trains suffer from a considerable increase in scheduled delays when speed differences increase.
Place, publisher, year, edition, pages
Double-track, railway operation, railway capacity
Research subject Järnvägsgruppen - Kapacitet
IdentifiersURN: urn:nbn:se:kth:diva-12723OAI: oai:DiVA.org:kth-12723DiVA: diva2:318281
ProjectsFramtida infrastruktur och kvalitet i tågföring