Heterogeneity Measures and Secondary Delays on a Simulated Double-Track
2013 (English)In: Proceedings of the 5th International Seminar on Railway Operations Modelling and Analysis, Copenhagen, Denmark, 2013, 2013Conference paper (Refereed)
The demand for transportation on railways grows for each year and many railway lines are already used close to maximum capacity. One way to increase capacity is to reduce traffic heterogeneity. Heterogeneity is introduced when train services with different speeds operate on the same line. There are many definitions of heterogeneity in literature. Good measures are important in order to be able to quantify capacity lost due to heterogeneity, and consequently how capacity can be gained by reducing it. This paper analyse some of the existing measures as well as introduces a new one, Mean Pass Coefficient (MPC). Other measures analysed are: number of speed levels (SL), speed ratio of fastest to slowest train (SR), mean difference in free running time (MDFR) as well as sum of shortest headway reciprocals (SSHR) and sum of arrival headway reciprocals (SAHR).
Two infrastructure models of double-track lines with overtaking stations spaced at different intervals are simulated. A large number of timetables are created where traffic density as well as the mix of slower and faster trains is varied. Each timetable is characterized using the different definitions of heterogeneity and the results are used in regression analyses to determine their explanatory value with respect to secondary delays created in the simulations. Results show that MPC performs best closely followed by MDFR and SR, while SL is worse when it comes to explaining secondary delays. SSHR and SAHR also show good performance. The performance of the measures increases when primary delays are high, but is unaffected by interstation distance.
Place, publisher, year, edition, pages
Railway, delay, heterogeneity, simulation, regression
Transport Systems and Logistics
IdentifiersURN: urn:nbn:se:kth:diva-138247OAI: oai:DiVA.org:kth-138247DiVA: diva2:680648
5th International Seminar on Railway Operations Modelling and Analysis Rail Copenhagen 2013, May 13 -15, 2013
QC 201406022013-12-182013-12-182015-09-02Bibliographically approved