Author(s)

O. Lindfeldt

Abstract

Train services on single-track lines suffer from time losses due to crossings, imposed by the bidirectional traffic. The time losses are caused by constraints in the infrastructure and delay propagation, which give a stochastic contribution that varies from one crossing situation to the other. Two examples of infrastructure improvements that decrease the time loss are examined: increased track length at timetabled crossing stations and decreased inter-station distances. A mathematical model is used to evaluate these improvements. Longer station tracks seem to be very efficient when traffic intensity and delay variances are moderate. Shortened inter-station distances give less effect but are less sensitive to delay variance and give valuable additional line capacity. The model used assumes independence between crossing trains, which imposes a moderate capacity utilisation. In more congested situations simulation methods are needed to make more complex crossing patterns possible. Keywords: single-track, delay propagation, partial twin-track, inter-station distance. 1 Introduction On single-track lines train services often have lower average speed and worse punctuality than on twin-track lines. These facts are caused by the bidirectional traffic that calls for crossings. These crossings take place on crossing stations with two or more parallel tracks. In many cases the crossing itself leads to time

Keywords

single-track, delay propagation, partial twin-track, inter-stationdistance.