Konferensartikel

Train punctuality in the UK is focussed on measuring the time trains are booked to pass a fixed point and when that event occurs. What is not considered in this measurement of performance is whether the capacity of the system is being optimised. It is posited in this paper that performance needs to consider how closely the delivered train service matches the minimum time signals should be red for that pattern of train services. Any changes to the operation of the system that cause the signals to be red for longer than necessary will decrease system capacity and this will have a detrimental effect on delay per incident. This paper compares on-train data recorders (OTDR) from 2002 and 2018. It shows that average braking rates have declined from 4%g to 3.5%g. This will typically add 4 seconds per stop. Train lengths in the UK have also increased in this time, with a typical train length increase being from 8 to 10 cars. If the slower braking curves and longer trains are combined, and a hypothetical block joint positioned 300m from a stopping point, it can be shown that the signal in rear will take 8 seconds longer to clear on average today than in 2002. While the impact of these changes on time at destination can be easily demonstrated using distance/time graphs, the effect on the signalling system is more complex. The simulation system trenissimo has been used to show that the effect on a system of longer trains and slower braking curves is [x], with the system responding in a non-linear way to very small changes in train operations. It is posited that this is key reason for the increase in delay per incident currently being seen in the UK.

Braking, Capacity, Performance